Research paper on biography of FLORES A FORBES Essay

Research paper on memoir of FLORES A FORBES - Essay Example Attempting to establish that language and that character early is an unsafe endeavor. Nobody in 1959 anticipated the disturbance of the 60s, particularly the disobedience of the youthful. Deaths can burglarize a country of its pioneers, surprising wars can dry up the imperativeness of a race, and the untouchable endowment of initiative can make trust where despondency existed. A considerable lot of the significant patterns, obvious and underground, that will shape keeps an eye on life later on are available today. Ask not what your nation can accomplish for you, said John F. Kennedy in his debut discourse as President. Approach what you can accomplish for your nation. The words expressed for the century. The traditionally adjusted rhythms, the request to obligation and nationalism sound unbelievably nostalgic to ears become used to a time of yells of crude energy, discordant dissent and brutality. The brilliant guarantee that started the 60s went to disarray and close to surrender as the decade finished. President Kennedys rendition of U.S. show fate appeared to be trailed by what Psychiatrist Frederick Hacker calls a meeting with show ludicrousness. The ludicrousness was apparent in the differentiating patterns of the decade. It was a time of amazing thriving, and of the disclosure of neediness, craving and social foul play at home. Opposing the liberal schedule, the irate dark and the irritated white, the G.I. in Viet Nam and the dissident at home would barely perceive the decade as sentimental. Intentionally, or accidentally, the period has become overregulated, over arranged, over industrialized, suddenness was lost; rather, there was uninhibited arrival of feelings. To an enormous degree, the substance of Forbes’ journal can be summed up through a wonderful piece composed by Claude McKay during the early time of the twentieth century; a long time before the projections; point by point in the book, have happened. The journal, on a genuine note is a glance back at the unrest of the 60s

Discuss the major components of an academic essay,outlining the role that each component plays. Essay

A scholastic paper is a methodical bit of composing which has a cognizant and attachment meaning. Fundamentally, a scholastic paper is principally described by a presentation, the body, the end and the reference as will be talked about forward with. In the first place, a presentation as worried by McMillan and Weyers (2010: 90) â€Å"has to be the primary contact that the peruser makes with the creator of the text.† This, thusly implies it (the presentation) must be efficient and clear, that is, short and exact to the topic or the theme. In help, Cleary et al (2013: 264) composes, â€Å"The presentation is the official beginning of your paper and acquaints your peruser with the subject.† Furthermore, Gamble and Gamble (2010: 371) underpins the possibility of the acquaintance being the first with dazzle the topic or focuses to be pushed. They further clarify that, â€Å"The elements of an acquaintance are with gain the consideration of the crowd individuals, to cause them to tune in to the speech.† Just like Gamble, Payne (2001) gives an accentuation on getting the consideration of the crowd through presenting the subject. Payne (on the same page) proposes that, the acquaintance has with realize the point, that is, featuring the crowd or the peruser about the subject or theme. Notwithstanding that, Gamble (in the same place) further shows that, in the presentation one of a definitive objectives to be manufactured is compatibility. This hence, implies making or having a shared connection of comprehension with the crowd. Cleary (2013: 265) recommends that, â€Å"an acquaintance has with clarify the title as essential: characterizing terms utilized in the title and clarifies the reason recorded as a hard copy the subject matter.† This implies, teaching the crowd or peruser about the theme and accordingly, giving sufficient data identifying with the subject. Likewise, McMillan (on the same page) gives an accentuation on the significance of the presentation being brief and, subsequently clarifying of the subject setting. Which means the acquaintance has with be clear and making the subject being plainly comprehended by everybody. Pritchard (2008) likewise features on the detailing of the connection between the crowds in order to convey the data successfully. All the more in this way, Payne (in the same place), further blueprints that the job of the acquaintance is with make focusting of the significant thoughts of the topic. Once more, this makes the guide of the remainder of the bit of work or archive or discourse, giving bearings and features of what will occur through the course of the composition. In help, McMillan (2010:89) recommends that, â€Å"an presentation ought to have a clarification of how one is going to plan to address the theme in a specific book as a result explanation on intent.† Moreover, Cleary (2013: 265) proposes that, â€Å"an acquaintance has with quickly express the structure of the paper by giving the primary points.† This along these lines gives the peruser a reasonable picture on the title, the motivation behind composition, the concentration and the article structure composes. Moreover, a presentation ought not be too hard to even think about understanding. The utilization of basic language which is generally acknowledged gives believability and the utilization of languages it ought not be utilized while presenting a theme. There ought not be any uncertainty while presenting a point. After the presentation, a scholarly article ought to have the body. This, as composes Payne (2001: 416), â€Å"Is the fundamental bit of the speech.† This subsequently, implies the utilization of good joints of sentences is generally energized. This part along these lines gives the real factors, proof, basic investigation, conversation and an all around d eveloped side line of the story or the subject. Thus, the primary thoughts or the essence of the theme are effectively achievable proficiently. Notwithstanding, McMillan et al shows that, â€Å"This segment (the body) spreads out the work dependent on the methodology which one has chosen to receive in sorting out the content.† This piece of the article should be managed incredible consideration, as arranging the data is pivotal. Since the thought needs legitimate and pivotal arrangement, this along these lines clarifies the significance of a decent paper structure with a decent arranging of words and an intelligible of good words in sentence development. Clouse (2008) attests that, the body comprises of two significant parts which are the subject sentence and the supporting subtleties. The theme sentence needs to introduce the fundamental subject of the passage and reports the paragraph’s primary thought, giving a guide. Additionally, the supporting subtleties are the proof subtleties gave to exhibit reality with regards to the point sentence. As such, the body needs to clarify the significant focuses, summing up, portraying or representing as a major aspect of the examination (McMillan). Furthermore, these creators additionally insinuate on keeping the body part as succinct and clear as could reasonably be expected; this subsequently implies the body must have less equivocalness in it. CEES (ed.) hails that the body some portion of a scholarly exposition composing needs to effectively give proof, models, references which identifies with the point sentence. This accordingly, gives the crowd a reasonable and an all around chara cterized image of what is being implied by the point sentence in play. Furthermore, CEES on the same page calls attention to that, the body presents the subject sentence or the focal thought supporting the thesisâ statement or line of contention. In accordance with Cleary (2013: 135-136), sections ought to be all around developed and of importance and this is when sentences are orchestrated so that they connect to each other offering lucidity to the peruser. Such cognizance can be accomplished by orchestrating the sentences in the arrangement that will best impart the message to the peruser through the incorporation of sign words or signals which manages the peruser. Likewise, a smooth progression of thoughts makes the paper substantially more fascinating, that is, strong significance of the considerations or thoughts relating to the point being talked about. Once more, this uses advances between sections so as to guarantee an ideal progression of thoughts. Nonetheless, the end in an exposition effectively summarizes the introduction. All the more thus, McMillan (91) characterizes a decision as an outline of the entire bit of work. In this manner, a great end needs to introduce and explain what has been examined, assessed, broke down, and expressed in the perfect work of art (the body) gathering of the article. Besides, Redman (2006) gives an accentuation that, legitimate ends needs to return to the key focuses or the primary concerns of one’s contention, summing up the key discussions raised and attempt to meld them. Subsequently, the decision ought to give a consolidated rendition of the essay’s center contention, and repeating the writer’s position in article. Likewise, Cleary in the same place implies that, in the end, thoughts not referenced before ought not be presented as this accordingly changes the focal point of the end. Payne in the same place (2001: 424), demonstrates that, â€Å"Conclusion is the summing up of the major ideas.† One doesn't need to survey everything said in the discourse, however a short piece helps the crowd to remember what is significant. The end needs to effectively clarify the issues or thoughts one has recently talked about. Notwithstanding that, Cleary in the same place says, â€Å"The part of an end is to fill in as an outline of the central matters, ordinarily alluding to the proposition statement.† Besides filling in as a synopsis, a great end ought to be utilized to elevate the effect of the introduction composes Gamble (2010: 374). The determination must be an engineered synopsis which along these lines gives a foundation of common comprehension. Besides, it must elegance the bit of work in such a way, that the significant crowd takes note of the significant focuses or thoughts of the rundown all in all (Payne). This implies, a great end must be defended for suggestions. Once more, an end ought to be short, explaining and accentuating on the principle subject of the composition, or the topic. Along these lines, this goes about as an instrument in making the introduction of the remainder of the point to be very much recalled through a propping end (Payne on the same page). To grasp more on a decent scholastic paper, references ought to be made in order to acclaim crafted by others (A2Z Essay). Cleary on the same page (2013: 361) characterizes, â€Å"Referencing as a normalized strategy for recognizing printed or electronic wellsprings of data and thought that one have utilized in the exposition, in a way that interestingly distinguishes their source.† Furthermore, referencing is a demonstration of back recognizing crafted by others in any obtained reality in order to guard crafted by others from any literary theft claims (A2Z). Basically, referencing is important to stay away from copyright infringement; to empower perusers to check citations; and to empower perusers to development and read all the more completely refered to author’s contention or research. O n another note, reference gives verification that permits the perusers or crowds to counsel the source if there should arise an occurrence of disarray or further conversations. Once more, references goes about as an appraisal device as in it expects one to discover unwavering quality of the wellsprings of the content, similitudes and contrasts among the sources and making association between the subtleties (

QA The Secret to Giving Your Salary Requirements

QA The Secret to Giving Your Salary Requirements You’ve worked really hard to look for a job that is in line with your skills and interest and when you finally get a call for an interview, you get all giddy and excited.So you take all of your graduating papers, scholarships and other educational certifications with you and prepare for some of the most common questions you could get asked like “tell us about yourself,” “how many years of experience do you have?” and “why should our company hire you?”It’s all going well until you finally get asked one question that never crossed your mind or doesn’t get thrown around often:“WHAT ARE YOUR SALARY REQUIREMENTS?” At this point, the interviewers would like to inquire about both your current and expected salary. The way to answer this depends on your level of experience and the wage rate is or was from your present or previous company respectively.You may be a tad nervous about responding especially because if you answer incorrectly or in a way that puts off your inte rviewer(s), you may lose the opportunity of getting this position.WHAT IF THE INTERVIEWERS INSIST?Sometimes companies will postpone this question for later after you’re on board and after your probation is done, but others may insist you answer before moving on with the rest of the interview process.You may get the salary question at the beginning of an interview depending on the type of company you’re going for which is what makes it a sneaky question. What you may not know is that it is a salary negotiation tactic that only looks like a gatekeeper-type interview question.If you want to know how to properly answer these questions, we’ll show you how, but first, let’s have a closer look at each of those questions and what they mean.“WHAT IS YOUR CURRENT SALARY?”This is the type of question usually asked of employees who are currently working elsewhere. It may come to you like this:What’s the least salary target we can offer you to switch companies?To some, this may b e the second time your new potential employer brought up this question and when they asked about your current salary then, they offered to pay you more.This most definitely is no coincidence and it’s not them wanting to pay you more than what you’re really worth. Let’s say that you told them your current salary was $45,000 and they offered to pay you $47,000. It does technically look like they’re “paying you more” but it’s not as you pictured it in your head.But we’re here to tell you that this is normal because the new company offered to pay you more than enough to entice you to leave your present job in order to work for them.The only upside to this deal is that you’re getting more than what you did from your current or last job, but the downside to it is that you could’ve gotten more if you hadn’t shared your current salary. You’ve got to be more strategic when it comes to salary negotiations.What is your expected salary?This is a bit tricky because it sou nds as though the interviewers wish to give you a chance to set the target for a new salary. It also sounds as if they’d like you to contribute to the job offer’s terms in hopes that you’ll consider.But let’s have a look at this question in another way just to unravel what they’re really asking you:“Can you guess the likely salary rate that we may pay someone with your skills and experience to do the job you’re applying for?”The best thing you can do is just guess because, in the end, you have no idea how much a company is willing to pay someone. That’s because the decision is dependent on a number of factors and most of which have nothing to do with your set of qualifications to perform this job.Some of those factors include:their hiring budgetthe number of positions they require in order to fill this jobHow badly they need to fill those positionsHow the company is doing in terms of profits, revenue, and growthSo when you think about it, answering the ‘salary ex pectations’ question involves just having you guess the number of factors that you can’t accurately fathom.But it might take an even worse turn from that point on.What are the chances that you’ll actually guess what they’re willing to pay someone of your skill set and experience for the position that they’re offering? It’s more of a rhetorical question because you can’t. You’d probably going to go over- or under-estimate the budget that they’re willing to offer.WHEN ANSWERING “WHAT ARE YOUR SALARY REQUIREMENTS?”It seems like a harmless enough question and it also makes sense that your employers would want to know a rough estimate of your expectations, right?Not exactly!You should be cautious when frankly stating your salary expectations way too early in the interview as it could lead to a set of problems.Problem 1: For starters, the organization isn’t exactly convinced that you’re even the right person for the job. They’re still just trying to get a good feel of the pool of prospects that are lined up for the same position. You can touch upon salary negotiations for later in the second part of your interview, but for now, it’s best to avoid naming a specific number right off the bat.Problem 2: You may be risking a move that sells you short and prevents going ahead with the rest of the interview. There may be some businesses who will offer the lowest price from the get-go, whereas others who understand the marketplace, will look to distance themselves from candidates who are too to lower their standards. It may also make them worry that you’ll lower your standards somewhere else.Also, ask yourself this, do you really want to work for a company that will offer the lowest deal possible? Or do you want to work for an organization that’s after the most qualified prospect for the job?Problem 3: If your price is too high, then it could put you out of the job seeking process before you can even get a chance to make a good impression. In fact, if you name a price that is out of their expectations, whether it is low or high, then you could lose your chance to vie for the position.Problem 4: If you give a price that’s too low, it could put you in a position where you can’t afford a job, yet at the same time, can’t turn it down either. This is true for candidates who offer low-end figures in hopes of getting a job or out of depression. This hardly ever leads to anything good.That’s why before you can even think about answering the question, we recommend that you do some research about the ideal price range for the jobs in your field and the job market. You can use the following websites to your advantage:payscale.comglassdoor.com/index.htmsalary.comThese sites will help you not only understand the market salary range for your potential position, but also the size of the company that’s interviewing you, the location as well as your experience level.Be advised that you may come across some sources with confl icting information, but least you’ll have a general sense of it as you go on.The goal is to come to an ideal salary range that is fair based on your current or recent salary and the market value. This way, you can name your price based on actual data and position it as the market range instead of going with your guts.Here are some of the price ranges for the architectural industry for instance:Source: RIBA AppointmentsHOW TO ANSWER THE “WHATS YOUR EXPECTED SALARY?” INTERVIEW QUESTION When the interviewers come to the “what are you looking for” part of the salary expectation question, consider this response:“I want to give myself an opportunity to move up in terms of both salary and compensation.”With this answer, you will show that you are willing to take up additional responsibilities so that you can be compensated as such for those contributions.HOW TO ANSWER THE “WHATS YOUR CURRENT AND EXPECTED SALARY?” INTERVIEW QUESTIONHere’s the best robust response to this kind of question:“I do not feel comfortable in sharing my current salary. I am more in favor of the amount of value that I would bring for this company, instead of how much my current company is paying me. At the moment, I do not have a target rate in mind and you already know what kind of value my skill set and experience can bring for your company. I want this to be a big leap for me in terms of both responsibility and compensation.”WHAT IF THEY ASK ME FOR MY SALARY AGAIN?The part where you avoided mentioning your salary expectation is just the first phase and that’s good.Many recruiters usually won’t bother asking such questions as it slows down the recruitment process because they wish to have this position filled just as badly as you want it.But others feel the need to ask you about your salary expectations so there’s no shaking that when it happens.But once you decline to share, some interviewers can check that off the list and move on with the rest of the interview .However, sometimes interviewers insist by saying something like:“We can’t move along without this relevant piece of information”Or“I need something to share with HR”The first thing to do is to repeat that you’re not comfortable at all in sharing that information:“As I said, I’m just not comfortable in sharing information about my current or expected salary. I would much rather focus on providing value to this company and look forward to hearing whatever you think is appropriate.”This works sometimes because employers are willing to try one last time in having you share your salary expectations. But other times, it just won’t fly because they insist on getting that information anyways.It may seem uncomfortable, but it’s all worth it.It’s good that you made it past two rounds with your employer from sharing your salary expectations. But if they didn’t give up, this can only mean that there may be a good chance that they’ll choose a candidate that is more a greeable for the job.Your current and expected salary expectations are two of three pieces of the following unique pieces of information that you have:Current salaryExpected salaryHow much you want the jobNow let’s compare this to your employer’s unique pieces of information:The salary range for the positionThe overall compensation budget they haveThe number of positions they’re trying to fill inHow long they’ve been trying to get this position filledHow much do they want to fill this positionHow much they prefer you over the other possible candidatesSo if you give them two pieces of information, you’re just down to one. Whereas the interviewers have more of other pieces of information than simply one.WHAT IF THEY STOP ASKING ME?They wontThe employer’s primary objective is to interview you because they’re in need of a qualified candidate. They also want to get a good deal from a candidate, after finding the right person for the job.If they’re pressing on with the sam e questions, it means they’re really interested in working with you, so they’re curious about getting a good deal from you.But what if they do?If they hold off the interview because you won’t share two of the three unique pieces of information with them, that means that your employers are very much looking forward to getting a bargain on your experience and skill set and are not, in fact, trying to find the right candidate for the job.That’s unfortunate for you, even if you do get the job. Because if that’s what they’re looking for instead of someone who fits the job requirements for the role, then you might as well say ‘no’.HOW TO NEGOTIATE WHAT YOURE WORTH  Congratulations! You’re getting hired! Only to be let down by the low-ball offer. But one thing to keep in mind is that it is what it is an offer. Which means that you have a chance to negotiate your way to a better deal and your interviewers are trying to test you.Your future with your potential new employer lies with how you respond to the offer. Here’s what you should do:Try to remain positive: This also applies to when the offer you’re getting is not one to be enthusiastic about. Always display a positive demeanor towards the offer and enthusiasm about being given the chance to opt for the position before you start negotiating.Make the offer you have in mind, one that is fair, backed by actual research and well-reasoned: You could provide a salary range as CBS Money suggests for a counter offer, which seems to imply that companies avoid offering the lowest range to escape from looking impolite.And when you do provide a range, please ensure that the bottom range is the one that you can work and live with. Salary ranges also give employers the indication that you’re flexible which is a trait they often want in their employees.Walk away if the offer isn’t right: This may be a hard one to do, especially in a competitive job market. But if you’re that persistent in earning you r livelihood, you may as well just hold back and wait until the right offer comes around, instead of opting for the next opportunity that comes knocking at your door.Other sources of compensation: While some companies have a limit on how much salary they can offer you for the job you seek, there are other ways to be compensated. Like if you cannot get the salary that you’re looking for, then try contributing in other ways to be rewarded, such as:Signing bonusesPerformance bonusesCompany stockAdditional vacation daysFuture pay raisesRetirement contributionsCompany stockFlexible work hoursHealth benefitsSome people can even bring in gym memberships for negotiations if you can believe that. But in the end, only you can determine your list of priorities. Don’t shy away from bringing it into talks, especially if they’re reasonable with your requests.If your interviewers are being deliberate about reiterating questions about your salary expectations, then it’s only fair that you b ecome just as deliberate about negotiating your desired price range as well.After all, those who don’t negotiate are the ones who are the most unhappiest as the chart below indicates:Source: Earnest SurveyBOTTOM LINEYou can’t be certain about the kind of “salary expectation” questions that interviewers will throw at you.And what’s important is that you shouldn’t have to live in fear about the kinds of questions that are on the low side of what you’re expecting.That’s why our strategies and suggestions are the best fail-safe chance of you making not only a killer impression on your interview, but also get a fair and reasonable price range.

Prediction of Corrosion Rate - Free Essay Example

Sample details Pages: 32 Words: 9741 Downloads: 4 Date added: 2017/06/26 Category Statistics Essay Did you like this example? Prediction of Corrosion Rate and Its Affecting Factors on Surface Casing Abstract Corrosion is a physicochemical phenomenon affected by multiple factors. The effect of these factors on corrosion depends on their concentrations and interactions with each other. It is not possible to establish a direct one to one relationship between the values of a single parameter and the corrosion rate while neglecting other parameters. Don’t waste time! Our writers will create an original "Prediction of Corrosion Rate" essay for you Create order This requires calculation that considers interactions of different parameters with each other as well as their effect on the corrosion rate. As the impact of each parameter value on corrosion rate, considering value of other parameters, cannot be expressed with a simple equation, it is not possible to accurately and confidently generalize the effects of change in each parameter on the corrosion rate over an entire domain. Surface casing of the wells can cause serious hazards and possible blowout as a result of early corrosion. In different areas in the world, surface casing collapses as a result of downhole corrosion, casing cracking, and rupture under high-pressure-corrosion. Surface casings or conductor pipes cannot be excavated deep for repair because of safety concerns. Corrosion problems of the surface casing result from non-fined manufactured joints, presence of salt water in some formation beds, and the cement section that isolates formation from the casing. In the shallow part of the casing, corrosion can result from either local or areal electrochemical reaction. Keywords: CO2 Corrosion, Surface Casing, Corrosion Rate, NORSOK M-506. III List of Symbols A the cross sectional area in m2 B(index) the constant used in viscosity calculations C(index) the concentration of component CRT the corrosion rate at temperature T in mm/year D the pipe diameter in mm FH2O the water mass flow in humidity calculations Ftot the total mass flow in humidity calculations K(index) the equilibrium constant used in pH calculations KSP the equilibrium constant of iron carbonate KT the constant for the temperature T used in corrosion rate calculations LTR Linear Polarization Resistance OCTG Oil Country Tubular Goods P the total system pressure in bar QG the volumetric flow of gas in MSm3/d QL the volumetric flow of liquid (i.e. liquid hydrocarbons and water) in Sm3/d R w/o Re the Reynolds number S the wall shear stress in Pa T the temperature given in Kelvin. Tc the temperature given in C Tf the temperature given in F Tstd the temperature given in Kelvin at standard conditions (60 F/15.55 C) Z the compressibility of the gas a the fugacity coefficient f the friction factor fCO2 the fugacity of CO2 in bar f(pH)T the the pH factor at temperature T k the pipe roughness in m I the ionic strength given in molar pCO2 the CO2 partial pressure in bar pH2O the H2O vapour pressure in bar T the 20 C, 40 C, 60 C, 80 C, 90 C, 120 C or 150 C uGS the superficial velocities of gas in m/s uLS the superficial velocities of liquid in m/s um the mixed velocity (m/s) the liquid fraction o the viscosity of oil in Ns/m2 G the viscosity of gas in Ns/m2 L the viscosity of liquid in Ns/m2 m the mixed viscosity in Ns/m2 relmax the maximum relative viscosity (relative to the oil) w the viscosity of water in Ns/m2 G the gas density in kg/m3 L the liquid density in kg/m3 m the mixed density in kg/m3 o the oil density in kg/m3 w the water density kg/m3 the watercut c the watercut at inversion point III Prediction of Corrosion Rate and Its Affecting Factors Introduction 1. Introduction Corrosion is defined as the chemical degradation of metals by reaction with the environment. The destruction of metals by corrosion occurs either by direct chemical attack at elevated temperatures in a dry environment or by electrochemical processes at low temperature in a water-wet or moist environment. Corrosion is the main threat to the petroleum industry. Its enormous impact is shown in Table 1.1. The values in the table may be assumed as average ones, because they vary regarding to the country and region e.g. in Western Europe corrosion-related failures come to ca. 25%, in the Gulf of Mexico and Poland about 50%, while in India they reach 80% (1) Table 1.1 Failures in Oil and Gas Industry (2) Type of failure Number of Cases [%] Corrosion (all types) 33 Fatigue 18 Mechanical damage/overload 14 Brittle fracture 9 Fabrication defects (excluding welding defects) 9 Welding defects 7 Others 10 The surface casing of wells located varies from a few hundred feet to as much as 5000 ft is prone to external corrosion attack at the splash zone around the wellhead region. The principal functions of the surface casing string are to: hold back unconsolidated shallow formations that can slough into the hole and cause problems, isolate the freshwater-bearing formations and prevent their contamination by fluids from deeper formations and to serve as a base on which to set the blowout preventers. It is generally set in competent rocks, such as hard limestone or dolomite, so that it can hold any pressure that may be encountered between the surface casing seat and the next casing seat. The effect of corrosion in surface casing ultimately results in loss of load bearing capacity of the wellhead when the severity is very high. At rig based well reentry, collapse of the surface casing had occurred under the weight of the Blow Out Preventer (BOP) during its installation. Historical records, field investigation and lab results from a previous study (SPE Paper 100432 and 108698) indicate the near surface casing corrosion is a result of cyclic or consistent moisture ingress of oxygenated water with the annulus between the Surface Casing and Conductor Casing. Elevated well operating temperatures in conjunction with an extremely corrosive environment caused by the salts that leach from the cement create a very aggressive corrosion environment. Corrosion of Surface casing itself can be distinguished based on its environment conditions ( 1.1) 1. Corrosion due to atmospheric condition (Zone I) 2. Corrosion due to corrosive water (Zone II) 3. Corrosion due to cementing (Zone III) 4. Internal Corrosion Prediction of Corrosion Rate and Its Affecting Factors Types of Casing Corrosion 2. Types of Casing Corrosion Casing is made by steel consists of alloy of pure iron and small amounts of carbon present as Fe3C with trace amounts of other elements such as Manganese, Molybdenum, Chromium, Nickel, Copper with particular purposes. In the most steel corrosion problems, the important differences in reaction potentials are not those between dissimilar metals but those which exist between separate areas interspersed over all the surface of a single metal. These potential differences result from local chemical or physical differences within or on the metal, such variations in grain structure, stresses and scale, inclusions in the metal, grain boundaries, scratches or other surface conditions. Corrosion of surface casing is initiated by a wide variety of mechanisms. They can be grouped into three categories: electrochemical corrosion, chemical corrosion, and mechanical assisted corrosion (3). 2.1 Electrochemical Corrosion Corrosion of casing is mostly electrochemical reaction composed of two half cell reactions, an anodic reaction and a cathodic reaction. The anodic reaction releases electrons, while the cathodic reaction consumes electrons (2.1 and 2.2). There are three common cathodic reactions, oxygen reduction (fast), hydrogen evolution from neutral water (slow), and hydrogen evolution from acid (fast). The corrosion cell can be represented as follows: * Anodic reaction: Fe Fe2+ + 2e- * Cathodic reactions: O2 + 4 H+ + 4e- 2H2O (oxygen reduction in acidic solution) 1/2 O2 + H2O + 2e- 2OH- (oxygen reduction in neutral or basic solution) 2H+ + 2e- H2 (hydrogen evolution from acidic solution) 2H2O + 2e- H2 + 2OH- (hydrogen evolution from neutral water) Electrochemical corrosion occurs above all on the outer casing wall. This type of corrosion can be subdivided into the following three sub-groups. 2.1.1 Galvanic Corrosion Galvanic corrosion is the most widespread type of corrosion and comes into being when two different metals or alloys develop a potential difference between them in a conducting electrolyte ( 2.3). The metal with the lower positive electrochemical potential acts as an anode and corrodes metal ions away to balance the electron flow. The second metal with higher positive electrochemical potential acts as a cathode and is protected from corrosion. If there were no electrical contact, both metals would be uniformly attacked by the corrosion. The severity of galvanic corrosion depends primarily upon the difference in potentials (the ranking of metal in galvanic series), their surface areas and environment (conductivity of the corrosive medium). 2.1.2 Crevice Corrosion This is an example of localized attack in the shielded areas of metal assemblies, shielded areas of metal assemblies. Crevice corrosion is caused by concentration differences of a corrodant over a metal surface. Electrochemical potential differences result in selective crevice or pitting corrosion attack. This kind of corrosion occurs at casing in poorly cemented sections as well as at drillpipe joints, tubing and casing collars ( 2.4). 2.1.3 Pitting Corrosion Pitting corrosion is similar to crevice corrosion and indicates a localized attack ( 2.5). Pitts are caused by a scratch, defect or impurity in casing. Pitting is one of the most dangerous forms of corrosion, because the metal loss can be rapid (even several mm per year) and often results in fast penetration. This type of corrosion is strongly affected by temperature. 2.2 Chemical Corrosion Chemical corrosion occurs mainly on the inner casing wall. It is governed by the chemical reactions that can not generate the electrical current. Characteristic chemical attacks are primary encouraged by carbon dioxide, hydrogen sulphide and organic or inorganic acids. 2.2.1 CO2 Corrosion CO2 corrosion or Sweet corrosion results from the presence of water containing dissolved carbon dioxide. Dissolved carbon dioxide in water decreases the pH of the water and increases its corrosivity. The following shows how CO2 results in the corrosion of steel: CO2 (g) + H2O (l) H2CO3 (aq) (Carbonic Acid) Fe (s) + H2CO3 (aq) FeCO3 (aq) + H2 (g) (Iron Carbonate) CO2 Corrosion in surface casing usually takes the form of deep pits with steep, undercut sides. This is sometimes referred to as mesa corrosion due to the shape of the pitting profile, i.e. areas of unattacked metal adjacent to pitted areas. The pits may penetrate the wall completely in a relatively short period of time. This pitting is caused when the carbon dioxide dissolves in water droplets that condense on the casing wall ( 2.6). The most serious sweet oil corrosion problem can usually be found in gas lift wells. They are usually high water producers, and corrosion can be accelerated if the injected gas lift gas contains carbon dioxide and/or small amounts of oxygen. 2.2.2 H2S Corrosion H2S Corrosion or sour corrosion is caused by hydrogen sulphide dissolved in water, which reacts with metal. Hydrogen ions are produced, which results in a more acidic environment, and low pH accelerates corrosion (especially in deep wells, where pH is further reduced by the pressure). Additionally iron sulphide is created, which at higher temperatures is cathodic to iron and leads to galvanic corrosion. Below is the chemical reaction to describe reaction between iron and H2S. Fe (s) + H2S (g) FeS (s) +2H In the presence of an oxidizing agent, the iron sulphide (FeS) deposited is cathodic to the steel and a galvanic cell can be set up. This may result in pitting of areas where the iron sulphide film has bee partially detached from the surface of the steel. An iron sulphide film that is adherent and undamaged can actually provide protection to the steel. 2.2.3 Strong Acids Corrosion Strong Acids Corrosion results from acids, which are pumped into the wells. They are mostly used to stimulate production like HCl in limestone formations or hydrofluoric acid for sandstones reservoir. Furthermore, dissolved oxygen stimulates corrosion in the presence of H2S and CO2. 2.3 Mechanical Assisted Corrosion The surface casing is considered to have low load level. Since the setting depth of surface casing is low, its main load is produced by BOP during the drilling phase and by other casing string strings hanging on it during production. However the Stresses in surface casing can increase corrosion especially on the casing joints and collars. This type of corrosion can be divided into several groups 2.3.1 Corrosion Fatigue When surface casing is repeatedly stressed in a cyclic manner, it will fail in a brittle manner at stresses far below the yield or tensile strength of the material ( 2.8). There exists a limiting stress below which steel may be cyclically stressed indefinitely without failure. This stress is called the endurance limit and is always lower than the yield and tensile strengths. The fatigue life of casing is substantially reduced when the casing is cyclically stressed in a corrosive environment. The simultaneous occurrence of cyclic stress and corrosion is called corrosion fatigue, and the steel no longer exhibits an endurance limit. In corrosion fatigue, the corrosivity of the environment is extremely important. The presence of dissolved gases especially oxygen carbon dioxide or The presence of dissolved gases, especially oxygen, carbon dioxide or hydrogen sulphide, results in a pronounced reduction in fatigue life. Pitting or localized attack is most damaging to fatigue life, but even slight general corrosion will substantially reduce time to failure. 2.3.2 Sulphide Stress Cracking (SSC) Sulphide stress cracking is a spontaneous brittle failure that occurs in steels and high strength alloys when exposed to moist hydrogen sulphide. This phenomenon is also referred to as sulphide cracking, sulphide corrosion cracking, and sulphide stress corrosion cracking. All the names refer to the same corrosion phenomenon, hydrogen embrittlement, which requires that hydrogen sulphide be present, water (even in small quantities) a high strength material, and tensile stress (either applied or residual). Sulphide stress cracking (SSC) may occur very rapidly after exposure to a sour environment, or it may take place after considerable time has passed. 2.3.3 Stress Corrosion Cracking (SCC) Stress corrosion cracking is caused by the synergistic action of a corrosive medium and applied tensile stress; that is, the combined effect of the two is greater than the sum of the single effects. In absence of the corrodant, the alloy could easily support the stress. The stress is always a tensile stress and can be either applied or residual. When a casing suffers stress corrosion cracking, metal loss from corrosion is generally very low, although most likely, pits will occur and the cracks will develop in the base of the pits. Stress Corrosion Cracking (SCC) of high strength casing steels occurs in salt solutions, moist atmospheres, and even in tap water if the steel is ultra high strength steel. Cracking tendency increases with the strength of the steel. Experience or testing is necessary to determine the corrosive and conditions which will cause cracking of high strength steels ( 2.6). It has to be added that the pure hydrocarbons are not corrosive themselves, so the corrosion is always initiated by other factors (most important are mentioned above). The market shares of individual corrosion mechanisms are presented in Table 2.1, however naturally they may occur simultaneously. Table 2.1 Causes of corrosion-related failure within the oil and gas industry (2) Cause of failure Total failure [%] CO2 related 28 H2S related 18 Preferential weld 18 Pitting 12 Erosion corrosion 9 Galvanic 6 Crevice 3 Impingement 3 Stress corrosion 3 45 Prediction of Corrosion Rate and Its Affecting Factors Corrosion Aspects of OCTG Materials 3. Corrosion Aspects of OCTG Materials 3.1 Introduction of OCTG Materials In recent years, oil and gas wells have been developed in increasingly severe corrosion environment characterized by high temperature, high partial pressure of CO2 and high concentration of Chloride ions, and in some cases, also containing H2S. For this reason, the prevention of corrosion in Oil Country Tubular Goods (OCTG) has become important task. OCTG includes three types of seamless tubes, delivered in quenched and tempered condition: * Drillpipe heavy seamless tubes that rotate the drill bit and circulate the drilling fluid. Joint of pipe 30 ft (9m) long are coupled together with tool joints. * Casing pipe is used to line the hole. * Tubing a pipe through which the oil and gas is produced from the wellbore. Tubing joints are generally around 30 ft (9m) long with thread connection on each end. The corrosion aspects of OCTG materials depend on their material contents such as Carbon, Chromium, Manganese, Nickel, Molybdenum and Copper. The tables below (Table 3.1 and 3.2) show the chemical compositions for OCTG grades of low alloy grades and stainless steel. Traditionally the grades used for OCTG applications were Carbon Manganese steels (up to the 55 ksi strength level) or Mo containing up to 0.4% Mo. Nowadays, wells with contaminants causing corrosive attack have strong demand for higher strength materials resistant to Hydrogen Embrittlement and Sulphide Stress Cracking (SCC). Highly tempered martensite has been identified as the structure which most resistant to SCC at higher strength level, and 0.75% Mo has been found to be the Mo concentration to obtain the optimum combination of yield strength and resistance to SCC (10). This is reflected in the list of Mo containing low alloy API standard grades (Table 3.1). For the 75 ksi strength level 0.4% Mo is sufficient, while each of the higher strength grades up to 125 ksi show the optimum Mo level of 0.75 or 0.80% and for higher strength up to 140 ksi (yield strength 965-1171 MPa) precipitated has been introduced as an additional strengthening mechanism by the addition of Niobium (Columbium). Table 3.1 Chemical Composition and Strength Properties of Common Alloy OCTG Steels (9) Yield strength API Grade % Alloy content Tensile Strength (ksi) Code C Mn Ni Cr Mo Cu min (N/mm2) 40 H40 0.5 1.5 410 55 K55 0.5 1.5 655 75 C75-1 0.5 1.7 0.5 0.5 0.4 0.5 665 90 C90-1 0.35 1.9 0.9 1.2 0.75 690 95 T95-1 0.35 1.2 0.9 1.5 0.85 724 125 Q125 0.35 1 0.9 1.2 0.75 930 140 0.3 1 1.6 1.1 0.05 1034 Table 3.2 Chemical Composition and Strength Properties of OCTG Stainless Steels (9) Yield strength API Grade % Alloy content Tensile Strength (ksi) Code C Mn Ni Cr Mo Cu min (N/mm2) 9% Chromium 75 C75-9Cr 0.15 0.6 0.5 9 1 0.25 655 13% Chromium 80 L80-13Cr 0.22 16 0.5 13 0.25 655 95/110 0.04 0.6 4 13 1.5 95/111 0.04 0.6 5 13 2.5 For service in oil and gas fields with more aggressive corrosion environments stainless API grades are standardized with 9% Cr, 1% Mo and 13% Cr (without Mo). For high temperature environments with CO2 and H2S, the non API specialized grades shown in table 3.2 with improved corrosion and SCC resistance have been developed (11). The reduced Carbon content increases Cr in solid solution, which effectively improves the corrosion resistance. Ni and Mo secure both hot workability and corrosion resistance. In particular the addition of Mo improves the pitting corrosion resistance, thereby eliminating initiation sites for SCC. 3.2 Influence of Microstructure and Chemical Composition of Steel in Corrosion Behavior Steel is an alloy of iron (Fe) and carbon (C). Carbon is fairly soluble in liquid iron at steel making temperatures, however, it is practically insoluble in solid iron (0.02% at 7230C), and trace at room temperature. Pure iron is soft and malleable; small amounts carbon and manganese are added to give steel its strength and toughness. Most of the carbon is oxidized during steelmaking. The residual carbon and post-fabrication heat treatment determines the microstructure, therefore strength and hardness of steels. Carbon steels are then identified by their carbon contents, i.e., low-carbon or mild steel, medium carbon (0.2- 0.4 % C), high-carbon (up to 1% C) steels, and cast irons (2 % C). In a corrosive environment, either grains or the grain boundaries having different composition can become anodic or cathodic, thus forming the corrosion cells. Hydrogen evolution reaction can take place on iron carbide, and spheroidized carbon in steels, and graphite in cast irons, in acidic solutions with relative ease; areas denuded in carbon become anodic and corrode preferentially. Therefore, post-weld heat treatment of steels is critical in order to prevent corrosion of the heat affected zone (HAZ), sensitization and intergranular corrosion in stainless steels The final microstructure of carbon and low alloy carbon steel OCTG is determined by its chemical composition and the thermomechanical treatments used during the production processes. Although the design criteria are mainly focused on properties such as mechanical resistance, toughness, and weld ability, the corrosion resistance is also affected. The microstructure is considered to have an important effect on how firmly the corrosion scale sticks to the surface. The adherence of the corrosion product film, and hence its protectiveness, has often been related to the presence of iron carbide and its morphology (laminar, globular, etc.). The idea is that the carbide phase can strengthen the film and can anchor it to the steel substrate, and then the size and distribution of these carbides become very important. Table 3.3 shows the typical corrosion characteristics of different types of steel. The table indicates that metals which have similar chemical composition will have different behavior in corrosion depend on their microstructures. Table 3.3 Typical Corrosion Characteristics of Different Types of Steel. (12) Item Martensitic Ferritic Austenitic Duplex Corrosion resistance to General Corrosion Fair Excellent Excellent Excellent Corrosion resistance to SSC Poor Poor Excellent Fair Corrosion resistance to SCC Excellent Excellent Poor Fair Strength High Low Low High Weldability Fair Fair Excellent Fair In order to prevent possible stress corrosion cracking in sour gas and oil wells containing CO2 and H2S with specific partial pressure, it is necessary to use specially manufactured tubing and casing. 3.1 below is a concept for material selection according to CO2 and H2S partial Pressure. Prediction of Corrosion Rate and Its Affecting Factors Corrosion of Surface Casing and Affecting Factors 4. Corrosion of Surface Casing and Elements Affecting of Corrosion Rate 4.1 Corrosion due to Atmospheric Corrosion Atmospheres are often classified as being rural, industrial or marine in nature. Two decidedly rural environments can differ widely in average yearly temperature and rainfall patterns, mean temperature, and perhaps acid rain, can make extrapolations from past behavior less reliable. The corrosion of casing steel in the atmosphere and in many aqueous environments is best understood from a film formation and brake down standpoint. It is an inescapable fact that iron in the presence of oxygen and water is thermodynamically unstable with respect to its oxides. Because atmospheric corrosion is an electrolytic process, the presence of an electrolyte is required. This should not be taken to mean that the steel surface must be awash in water; a very thin adsorbed film of water is all that is required. During the actual exposure, the metal spends some portion of the time awash with water because of rain or splashing and a portion of the time covered with a thin adsorbed water film. The portion of time spent covered with the thin water film depends quite strongly on relative humidity at the exposure site. This fact has led many corrosion scientists to investigate the influence of the time of wetness on the corrosion rate. Rusting of iron depends on relative humidity and time of exposure in atmosphere containing 0.01% SO2. The increase in corrosion rate produced by the addition of SO2 is substantial. Oxides of nitrogen in the atmosphere would also exhibit an accelerating effect on the corrosion of steel. Indeed, any gaseous atmospheric constituent capable of strong electrolytic activity should be suspected as being capable of increasing the corrosion rate of steel. Because carbon steels are not very highly alloyed, it is not surprising that most grades do not exhibit large differences in atmospheric-corrosion rate. Nevertheless, alloying can make changes in the atmospheric-corrosion rate of carbon steel. The elements generally found to be most beneficial in this regard are copper, nickel, silicon, chromium and phosphorus. Of these, the most striking example is that of copper, increases from 0.01-0.05%, decrease the corrosion rate by a factor of two to three. 4.2 Corrosion due to Water Environment Carbon steel casing is often submerged in water to some extent during service. This exposure can be under conditions varying temperature, flow rate, pH, and other factors, all of which can alter the rate of corrosion. The relative acidity of the solution is probably the most important factor to be considered. At low pH the evolution of hydrogen tends to eliminate the possibility of protective film formation so that steel continues to corrode but in alkaline solutions, the formation of protective films greatly reduces the corrosion rate. The greater alkalinity, the slower the rate of attack becomes. In neutral solutions, other factors such as aeration became determining so that generalization becomes more difficult. The corrosion of steels in aerated seawater is about the same overall as in aerated fresh water, but this is somewhat misleading because the improved electrical conductivity of seawater can lead to increased pitting. The concentration cells can operate over long distance, and this leads to a more nonuniform attack than in fresh water. Alternate cycling through immersion and exposure to air produces more pitting attack than continuous immersion. The effect of various alloying addition and exposure conditions on the corrosion behavior is shown in Table 4.1. Table 4.1 Comparison of results under different type of exposure (13) Effects of alloy selection, chemical composition and alloy additions Sea air Freshwater Alternately wet with Seawater or Spray and dry Continuously wet with seawater Ferrous alloys Pockmarked Vermiform on cleaned bars Pitting, particularly on bars with scale Pitting, particularly on bars with scale Wrought iron versus carbon steel Steel superior to wrought and ingot irons Iron and steel equal in low-moor areas Low-moor iron superior to carbon steel Low-moor iron superior to carbon steel Sulfur and phosphorus content Best results when S and P are low Best results when S and P are low Best results when S and P are low Apparently little influence Addition of copper Beneficial: Effect increasing with copper content Beneficial: 0.635% Cu almost as good as 2.185% Cu Beneficial: 0.635% and 2.185% Cu much the same 0.635% Cu slightly beneficial: 2.185% Cu Addition of nickel 3.75% Ni Superior even to 2% Cu; 36% Ni almost Perfect after 15-year exposure 3.75%Ni Superior even to 2%Cu; 36%Ni excellent resistance 3.75%Ni beneficial usually more so than Cu: 36%Ni the best metal in the set 3.75% Ni slightly beneficial and slightly superior to Cu: 36% Ni the best metal in the set Addition of 13.5% Cr Excellent resistance to corrosion: cold blast metal perfect after 15-year exposure: equal to 36% Ni steel Excellent resistance to corrosion: equal to 36% Ni steel Subject to severe localized corrosion that virtually destroys the metal Subject to severe localized corrosion that virtually destroys the metal Behavior of cast irons Excellent resistance to corrosion: cold blast metal superior to hot: no graphitic corrosion Undergoes graphitic corrosion Undergoes graphitic corrosion Undergoes graphitic corrosion Interestingly, the corrosion rates of specimens completely immersed in seawater do not appear to depend on the geographical location of the test site; therefore, by inference, the mean temperature does not appear to play an important role. This constancy of the corrosion rate in seawater has been attributed to the more rapid fouling of the exposed steel by marine organisms, such as barnacles and algae, in warmer seas. It is further speculated that this fouling offsets that increases expected from the temperature rise. 4.3 Corrosion due to Cement Environment 4.3.1 Cement as an Environment for Casing Steel and the Role of Alkalinity Cementing is one of the fundamental techniques in oil and gas well design approach. It serves its purpose as a protective material in preventing the casing from corrosion. Environment formation characteristics such as mineral content, microorganisms, acidity lead to steel corrosion and this could be prevented by cementing. Cementing is one method to surround the steel with an alkaline environment having a pH value within the range 9.5 to 13. Hydrated cement provides such an environment, the normal pH value being 12.5, at which steel is protected in the absence of aggressive anions. At this pH value a passive film forms on the steel that reduces the rate of corrosion to a very low and harmless value (Fig 4.1). Thus, cement cover provides chemical as well as physical protection to the steel. However, circumstances do arise in which corrosion of reinforcement occurs. Since rust has a larger volume than the steel from which it is formed, the result can be cracking, rust-staining, or even spalling of the cement cover. Such occurrences usually arise from loss of alkalinity in the immediate vicinity of the steel or from the presence of excessive quantities of aggressive anions in the cement (normally chloride), or from a combination of both of these factors. 4.3.2 Loss of Alkalinity by Carbonation Alkalinity can be lost as a result of: * Reaction with acidic gases (such as carbon dioxide) in the atmosphere. The effects of sulphur dioxide are also included in the term carbonation. * Leaching by water from the surface. In practice both of these factors contribute to the reduction of alkalinity in the cement. Cement is permeable and allows the slow ingress of the atmosphere; the acidic gases react with the alkalis (usually calcium, sodium and potassium hydroxides), neutralizing them by forming carbonates and sulphates, and at the same time reducing the pH value. If the carbonated front penetrates sufficiently deeply into the cement to intersect with the cement reinforcement interface, protection is lost and, since both oxygen and moisture are available, the steel is likely to corrode. The extent of the advance of the carbonation front depends, to a considerable extent, on the porosity and permeability of the cement and on the conditions of the exposure. 4.3.3 The Effect of Chloride in The Cement The passivity provided by the alkaline conditions can also be destroyed by the presence of chloride ions, even though a high level of alkalinity remains in the cement. The chloride ion can locally de-passivity the metal and promote active metal dissolution. Chlorides react with the calcium aluminates and calcium aluminoferrites in the cement to form insoluble calcium chloroaluminates and calcium chloroferrites in which the chloride is bound in non-active form; however, the reaction is never complete and some active soluble chloride always remains in equilibrium in the aqueous phase in the cement. It is this chloride in solution that is free to promote corrosion of the steel. At low levels of chloride in the aqueous phase, the rate of corrosion is very small, but higher concentration increases the risks of corrosion. Thus the amount of chloride in the cement and, in turn, the amount of free chloride in the aqueous phase (which is partly a function of cement content and also of the cem ent type) will influence the risk of corrosion. While the cement remains in an uncarbonated state the level of free chloride in the aqueous phase remains low (perhaps 10% of the total Cl). However, the influence of severe carbonation is to break down the hydrated cement phases and, in the case of chloroaluminates, the effect is to release chloride. Thus more free chloride is available in carbonated cement than in uncarbonated materials. 4.4 Elements Affecting of Corrosion Rate 4.4.1 Water Chemistry Water chemistry is probably the most influential parameter affecting corrosion. The situation can vary from being very simple with only a few carbonic species present, as in the case with condensed water in gas pipelines, to being very complex with numerous species found for example in formation water emerging together with crude oil. In some cases the concentration of dissolved salts can be very high ( 10 wt %) making the solution non-ideal. Table 4.2 contains an overview over dissolved species can be found in formation water. Table 4.2 Dissolved Species that can be found in Formation Water (13) Specie Description CO2 Dissolved carbon dioxide H2CO3 Carbonic acid HCO3- Bicarbonate ion CO3- Carbonate ion H+ Hydrogen ion OH- Hydroxide ion Fe2+ Iron ion CH3COOH (HAc) Acetic acid H2S Dissolved hydrogen sulphide S- Sulphide ion SO4- Sulphate ion Cl- Chloride ion Na+ Sodium ion K+ Potassium ion Ca2+ Calcium ion Mg2+ Magnesium ion Ba2+ Barium ion CH3COO- (Ac-) Acetate ion HSO4- Bisulphate ion O2 Dissolved Oxygen Understanding the brine chemistry is important to be able to predict corrosion rate since pH is one of the most important parameters when calculating the corrosion rate. pH depends strongly on the water chemistry. 4.4.2 The Effect of pH Experience has shown that pH has a strong influence on the corrosion rate. Typical pH in pure water is about 4, while pH in buffered brines normally is in the range 5 7. At pH 4 (and lower) direct reduction of H+ ions is important particular at lower partial pressure of CO2 and the pH has a direct affect on the corrosion rate. However, the most important effect of pH is indirect and relates to how pH affects conditions for formation of iron carbonate films. High pH results in a decreased solubility of iron carbonate and lead to an increased precipitation rate and higher scaling tendency; reflected by a rapid decrease of the corrosion rate with time. When calculating corrosion rates, it is of vital importance to have as accurate as possible pH value for the actual exposure condition either from: * Direct measured values (easy in lab, difficult in the field) * pH calculation tool in addition to reliable water chemistry analysis 4.4.3 The effect of CO2 Partial Pressure In case of film-free CO2 corrosion, an increase in partial CO2 pressure (PCO2) typically leads to an increase in the corrosion rate. The commonly accepted theory is that with PCO2 the concentration of H2CO3 increases and accelerates the cathodic reaction, and ultimately the corrosion rate. At a constant pH, higher PCO2 leads to an increase in CO32- concentration and a higher supersaturation, which accelerates precipitation and film formation. 4.4.4 The effect of HAc Since acetic acid HAc is a stronger acid than carbonic acid (H2CO3), it is the main source of hydrogen ions when the two acid concentrations are similar. The effect of HAc is particularly pronounced at higher temperatures where the presence of HAc can increase the corrosion rate dramatically. 4.4.5 The effect of Temperature Temperature accelerates all the processes involved in corrosion. One would expect that the corrosion rate steadily increases with temperature. This is the case at low pH when precipitation of iron carbonate or other protective films does not occur. The situation changes markedly when solubility of iron carbonate (or other salt) is exceeded, typically at high pH. In that case, increased temperature accelerates rapidly the kinetics of precipitation and protective film formation, decreasing the corrosion rate. The peak in the corrosion rate is usually seen between 60 and 800C depending on water chemistry and flow conditions; see 4.2 as an example. Prediction of Corrosion Rate and Its Affecting Factors Corrosion Model and Calculation of Corrosion Rate 5. Corrosion Model and Calculation of Corrosion rate 5.1 Introduction of Corrosion Model Corrosion of carbon steel alloys has been, and remains, a major cause of corrosion damage in oil and gas field operations. The industry relies heavily on the extensive use of these materials, and thus there is a desire to predict the corrosivity of CO2-H2S containing hydrocarbons when designing wellbore, production equipment and transportation facilities. A true industry standard approach to predict CO2-H2S corrosion does not exist although there are aspects of commonality between the approaches/models offered by the industry and the research organizations. The Shell equation or nomogram was developed as an engineering tool. It presents, in a simple form, the relationship between potential corrosivity of aqueous media for a given level of dissolved CO2-H2S, defined by its partial pressure, at any given temperature. The NORSOK M-506 model is an empirical model mainly base don laboratory data at low temperature and a combination of lab and field data at temperatures above 1000C. The NORSOK model takes larger account for the effect of protective corrosion films and therefore predicts lower corrosion rates at high temperature and high pH than other models. The model does not take any effect of oil wetting. The model has been developed by Statoil, Hydro Oil Energy and Saga Petroleum, and has been issued as a NORSOK standard for the Norwegian Oil industry. The spreadsheet with the model is openly available on its website. 5.2 Corrosion Model based on NORSOK M-506 rev.2 The model is an empirical corrosion rate model for carbon steel in water containing CO2-H2S with particular ratio at different temperatures, pHs, CO2-H2S fugacities and wall shear stresses. It is based on flow-loop experiments at temperatures from 5C to 150C. A large amount of data at various temperatures, CO2-H2S fugacities, pHs and wall shear stresses are used. The following general equation of the CO2-H2S corrosion rate for carbon steel at each of the temperatures (T); * 20C, 40C, 60C, 80C, 90C, 120C and 150C is used: CRT = KT x fCO2 0.62 x (S/19) 0.146 + 0.0324 log (fCO2) x f(pH)T (mm/year) (5.1) * The following equation is used at temperature 15C: CRT = KT x fCO2 0.36 x (S/19) 0.146 + 0.0324 log (fCO2) x f(pH)T (mm/year) (5.2) * The following equation is used at temperature 5C: CRT = KT x fCO2 0.36 x f(pH)T (mm/year) (5.3) The corrosion rate between temperatures where a constant Kt has been generated is found by a linear extrapolation between the calculated corrosion rate at the temperature above and below the desired temperature. The constant KT is given in the table below Table 5.1 Constant KT Temperature KT C 5 0.42 15 1.59 20 4.762 40 9 60 11 80 10 90 6 120 8 150 5 When the pH in the water increases the corrosion rate will decrease due to the reduction of the H+- ions in the water. In addition to this protective corrosion films may be formed on the steel surface and reduce the corrosion rate even more. It has not been distinguished between these two effects on the general corrosion rate in this study. The effect of pH is included in equation (5.4): * CRT = KT x fCO2 0.6 x f(S) x f(pH)T (mm/year) (5.4) Where f(pH)T is the effect of pH on the corrosion rate for each temperature T. The effect of pH was found by plotting measured corrosion rate divided by the product of KT, fCO20.6 and f(S). The effect of pH on corrosion rate at various temperatures is described by the functions in Table 5.2. The effect of pH on corrosion rate is different for all the temperatures. The effect of pH is given in Table 5.2. Table 5.2 pH Function Temperature pH f(pH) C 5 3,5 pH 4,6 f(pH) = 2,0676 (0,2309 x pH) 5 4,6 pH 6,5 f(pH) = 4,342 (1,051 x pH) + (0,0708 x pH2) 15 3,5 pH 4,6 f(pH) = 2,0676 (0,2309 x pH) 15 4,6 pH 6,5 f(pH) = 4,986 (1,191 x pH) + (0,0708 x pH2) 20 3,5 pH 4,6 f(pH) = 2,0676 (0,2309 x pH) 20 4,6 pH 6,5 f(pH) = 5,1885 (1,2353 x pH) + (0,0708 x pH2) 40 3,5 pH 4,6 f(pH) = 2,0676 (0,2309 x pH) 40 4,6 pH 6,5 f(pH) = 5,1885 (1,2353 x pH) + (0,0708 x pH2) 60 3,5 pH 4,6 f(pH) = 1,836 (0,1818 x pH) 60 4,6 pH 6,5 f(pH) = 15,444 (6,1291 x pH) + (0,8204 x pH2) (0,0371 x pH3) 80 3,5 pH 4,6 f(pH) = 2,6727 (0,3636 x pH) 80 4,6 pH 6,5 f(pH) = 331,68 x e(-1,2618 x pH) 90 3,5 pH 4,57 f(pH) = 3,1355 (0,4673 x pH) 90 4,57 pH 5,62 f(pH) = 21254 x e(-2,1811 x pH) 90 5,62 pH 6,5 f(pH) = 0,4014 (0,0538 x pH) 120 3,5 pH 4,3 f(pH) = 1,5375 (0,125 x pH) 120 4,3 pH 5 f(pH) = 5,9757 (1,157 x pH) 120 5 pH 6,5 f(pH) = 0,546125 (0,071225 x pH) 150 3,5 pH 3,8 f(pH) = 1 150 3,8 pH 5 f(pH) = 17,634 (7,0945 x pH) + (0,715 x pH2) 150 5 pH 6,5 f(pH) = 0,03 The corrosion rates at temperatures between 20 and 400C, 40 and 600C, 60 and 800C and so on should be calculated by linear interpolation between the corrosion rates calculated with equation (5.4) at these temperatures. The pH has a significant effect on the corrosion rate for all the temperatures. One interesting observation is that the maximum corrosion rates vary between 40 and 90C depending on the pH. To predict the pH in the condensed water or formation water, the parameters given in Table 5.3 are needed. Table 5.3 Input Parameters for pH Calculation Parameter Unit Range Default values Comments Temperature C 5 to 150 F 41 to 302 Total pressure bar 1 to 1000 psi 14,5 to 14500 Total mass flow kmole/h 10 to 106 Only relevant when CO2 is given in kmole/h CO2 fugacity bar 0 to 10 The CO2 partial pressure shall be lower than the psi 0 to 145 total pressure.The allowed ranges of mole% and mole% variable kmole/h CO2 are dependent on the total pressure. kmole/h variable Bicarbonate (HCO3-) mg/l 0 to 20000 0 Default values for formation water. mM 0 to 327 Ionic strength/salinity g/l 0 to 175 50 Default values for formation water. M 0 to 3 The routine for calculation of pH is based on the following chemical reactions and equilibrium constants: The system has to be electro-neutral, which can be described by the following equation: (5.5) It is assumed that bicarbonate is added as sodium bicarbonate (NaHCO3). It is also assumed that no other salts than sodium bicarbonate and sodium chloride (NaCl) are present in the solution. These salts will dissolve as follows: Based on these assumptions, the amount of sodium bicarbonate equals the difference in the concentrations of sodium and chloride as shown below. The mass balance for bicarbonate will therefore be as follows: (5.6) C0, Bicarb equals the initial amount of sodium bicarbonate. By combining the equations for the equilibrium constants with the required electro-neutrality and the mass balance for bicarbonate one gets the following expression for the concentration of the hydrogen cation: (5.7) This equation is solved by using the Newtons method. The pH in a condensed water system saturated with iron carbonate can also be calculated. Based on a similar deduction as above, the equation becomes: (5.8) Where (5.9) Gases are not ideal at high pressures. To compensate for this, the partial pressure of a gas is multiplied by a fugacity constant. The real CO2 pressure can then be expressed as: (5.10) The CO2 partial pressure is found by one of the following expressions (5.11) The fugacity coefficient is given as (5.12) 45 Prediction of Corrosion Rate and Its Affecting Factors Discussions of Results 6. Corrosion Rate Results and Discussions Using Equations in sub-chapter 5.2, the charts of corrosion rate with several parameters on basis of given temperature, pH, CO2 partial pressure and shear stress have been generated with several assumptions as describe below: * The model is valid for temperature 5 150 C, pH 3.5 6.5, * CO2 partial pressure 0.1 10 bar and shear stress 1 150 Pa. * The model is not applicable when the H2S partial pressure is higher than 0.5 bar, * or when the ratio between the partial pressure of CO2 and H2S is less than 20. * The model can lead to underproduction of the corrosion rate when the total content of organic acids exceeds 100 ppm and the CO2 partial pressure is less than 0.5 bar. 6.1 Effect of Temperature Corrosion rates as a function of temperature with specific amount of CO2 (in % mole) are shown in 6.1 to 6.12. The corrosion rates starts instantaneously still at low temperature due to continuous dissolution of Fe2+ ion in the solution. As the temperature increases corrosion rate increases due to the formation of porous iron carbonate films, results in the initiation of cracks and spallation of the oxide layers formed on the metal surface. The chloride ion easily ingress through the surface and significantly increases the corrosion at the temperature range of 40-80oC. Further increase in temperature the corrosion rate decreases significantly due to the formation of denser, adherent and homogeneous layer of iron carbonate, which is, protects the metal to further corrosion. As the partial pressure of CO2 in the solution increases the formation of weak carbonic acid (H2CO3) favors, which increases the corrosion rate. However at higher temperature the bicarbonate ions (HCO3-) formed on the surface gives more carbonate ions (CO32-) results in formation of more insoluble iron carbonate which increases the solution pH and corrosion rate decreases significantly as shown in 6.1-6.12 at 120oC. In many literatures, it has been reported that Fe2CO3 precipitation is temperature dependent and for its precipitation super saturation with the Fe2+ ion is required which is 5-10 times higher than the thermodynamically calculated values of solubility. (16) 6.2 Effect of pH The effect of various pH on Corrosion rates are shown in 6.1, 6.4, 6.7. Lower Corrosion rates are obtained at the higher pH, the corrosion rate does not change much with pH higher than 6.5, even if some ferrous carbonate precipitation occurs, reflecting the fact that a relatively porous, detached and unprotective layer is formed. There are other indirect effects of pH, and by almost all accounts, higher pH leads to a reduction of the corrosion rate, making the pH stabilization (meaning: pH increase) technique an attractive way of managing CO2 corrosion. 6.2,5,8,10,11,12 are described Corrosion rate at pH 4-4.4 at specific temperature (90-120oC) with various mole of CO2, CO2 partial pressure and shear stresses have constant corrosion rates compare to other corrosion rates with different pHs at similar temperature. The reason of this phenomenon is the acceleration of increasing formation of weak carbonic acid (H2CO3) during temperature 90-120oC which causes increasing corrosion rate has equal acceleration with the formation of iron carbonate which is formed on the surface of steel and create the passivity behavior. 6.3 Effect of Partial Pressure An increase in partial CO2 pressure (PCO2) typically leads to an increase in the corrosion rate. The commonly accepted theory is that with PCO2 the concentration of H2CO3 increases and accelerates the cathodic reaction, and ultimately the corrosion rate ( 6.2,3,4,5,6,8,9). However, when other conditions are favorable for formation of ferrous carbonate layers, increased PCO2 can have a beneficial effect. At a constant pH, higher PCO2 leads to an increase in CO32- concentration and a higher supersaturation, which accelerates precipitation and protective layer formation. With CO2 = 30% mole 6.4 Effect of Partial Pressure The effect of wall shear stress may have two different effects on the corrosion rate: * The general corrosion rate may increase with 10-30% as shown in Fig 6.10-12 * Local mesa attack may occur at high values of wall shear stress which can give corrosion rates which is 10-100 times higher than expected if the corrosion attach was general corrosion. Prediction of Corrosion Rate and Its Affecting Factors An Experimental Approach to Investigate Long Term Corrosion 7. An Experimental approach to Investigate Long Term Corrosion 7.1 Introduction of LPR method The LPR technique has become a well-established method of determining the instantaneous corrosion rate measurement of steel in cement structures. The technique is rapid and non-intrusive, requiring only localized damage to the cement cover to enable an electrical connection to be made to the steel or directly from steel to steel. Due to the widespread corrosion of steel in cement structures there has been a concerted demand for the development of non-destructive techniques to enable accurate assessment of the condition of steel. LPR monitoring has been developed to address this need. The technique is rapid and non-intrusive, requiring only a connection to the steel. The data provides a valuable insight into the instantaneous corrosion rate of the steel, giving more detailed information than a simple potential survey. The LPR data enables a more detailed assessment of the structural condition and is a major tool in deciding upon the optimum remedial strategy to be adopted. It is thus imperative that the LPR measurements obtained are accurate. In LPR measurements the steel is perturbed by a small amount from its equilibrium potential. This can be accomplished potentiostatically by changing the potential of the steel by a fixed amount, E, and monitoring the current decay, I, after a fixed time. Alternatively it can be done galvanostatically by applying a small fixed current, I, to the steel and monitoring the potential change, E, after a fixed time period. In each case the conditions are selected such that the change in potential, E, falls within the linear Stern-Geary range of 10-30 mV. The polarization resistance, Rp, of the steel is then calculated from the equation. (7.1) From which the corrosion rate, Icorr, can then be calculated (7.2) where, B is the Stern-Geary constant. A value of 25 mV has been adopted for active steel and 50 mV for passive steel. In order to determine the corrosion current density, icorr, the surface area, A, of steel that has been polarized needs to be accurately known: (7.3) The present residual strength and, by extrapolation, the remaining service life of the structure can be estimated. In a conventional LPR test the perturbation is applied from an auxiliary electrode on the cement surface. The surface area of steel assumed to be polarized is that lying directly beneath the auxiliary electrode. However, there is considerable evidence to suggest that the current flowing from the auxiliary electrode is unconfined and can spread laterally over an unknown, larger area of steel This can lead to inaccurate knowledge of the surface area of steel polarized and result in an error in the calculation of the corrosion current density, which, in turn, will produce an inaccurate estimate of the condition of the structure being investigated. In order to overcome the problem of confining the current to a predetermined area, the use of a second auxiliary guard ring electrode surrounding the inner auxiliary electrode has been developed. The principle of this device is that the outer guard ring electrode maintains a confinement current during the LPR measurement. This confinement current prevents the perturbation current from the main inner auxiliary electrode spreading beyond a known area. In order to select an appropriate level for the confinement current two sensor electrodes are placed between the inner and outer auxiliary electrodes. The potential difference between these sensor electrodes is monitored and a confinement current selected to maintain this potential difference throughout the LPR measurement. The performance of the guard ring has been shown to be an improvement upon that of a single unconfined auxiliary electrode, giving a more accurate value for the corrosion rate of the steel being monitored. At present the established method of guard ring LPR measurements uses galvanostatic control. This method relies upon the potential response, E, to the selected perturbation, I, falling within the linear region of the Stern-Geary plot. The use of a potentiostatic device would enable the potential shift itself to be selected, ensuring the measurement falls within this linear region and hence, would not risk the inaccuracies incurred by applying too large a galvanostatic perturbation. 7.2 Experimental Procedure Using the concept and principle of LPR, an experiment for monitoring and measurement corrosion of Surface casing can be developed. Casing steel is isolated with cement and flooded with water at certain level of high and CO2 is injected into water at certain level. The experiment can be done with several variables such as Temperature, CO2 composition in the water and salt contain ( 7.3). After certain period, corrosion on surface casing shall be monitored and measured using LPR tool. The both electrodes (reference and working electrode) can be placed inside of the casing or the reference electrode can be also placed on the cement surface as well. The result which is given by digital control system has to be calculated using equation 7-1-3 and compared by corrosion current table to determine condition of the steel. The following broad criteria for corrosion have been developed from field and laboratory investigations with the sensor controlled guard ring device given in Table 7.1 Table 7.1 Corrosion current vs. condition of the steel (18) Corrosion current (Icorr) Condition of the steel Icorr 0.1 A/cm2 Passive condition Icorr 0.1 0.5 A/cm2 Low to moderate corrosion (17.1 m/year) Icorr 0.5 1.0 A/cm2 Moderate to high corrosion (34 m/year) Icorr 1.0 A/cm2 High corrosion rate (345 m/year) The device without sensor control has the following recommended interpretation Icorr 0.2 A/cm2 No corrosion expected Icorr 0.2 1.0 A/cm2 Corrosion possible in 10 -15 years Icorr 1.0 10 A/cm2 Corrosion expected in 2-10 years Icorr 10 A/cm2 Corrosion expected in 2 years or less 45 Prediction of Corrosion Rate and Its Affecting Factors Conclusions 8. Conclusions 1. The Norsok M-506 model was used for this study allowed clear calculations of trends for the general corrosion rate for the carbon steel. The temperature range 5-1500C was particularly covered. The parameters of main importance were (in order of importance): the pH, the fugacity of CO2, temperature and the mean wall shear stress with several assumptions as describe below: * The model is valid for temperature 5 150 C, pH 3.5 6.5, * CO2 partial pressure 0.1 10 bar and shear stress 1 150 Pa. * The model is not applicable when the H2S partial pressure is higher than 0.5 bar, * or when the ratio between the partial pressure of CO2 and H2S is less than 20. * The model can lead to underproduction of the corrosion rate when the total content of organic acids exceeds 100 ppm and the CO2 partial pressure is less than 0.5 bar. 2. As the temperature increases corrosion rate increases due to the formation of porous iron carbonate films, results in the initiation of cracks and spallation of the oxide layers formed on the metal surface. 3. An increase in partial CO2 pressure (PCO2) typically leads to an increase in the corrosion rate. 4. The wall shear stress may have two different effects on the corrosion rate: * The general corrosion rate may increase with 10-30% dependent on the wall shear stress and fugacity of CO2. * Mesa attacks may occur at high values of shear stress. 5. Casing Steel which is isolated with cement will start to corrode when the cement loss alkalinity during its life time and cracking. 6. Linear Polarization Resistance method can be used to monitor and determine corrosion on surface casing Prediction of Corrosion Rate and Its Affecting Factors References References: 1. Samant, A.; Corrosion Problems in Oil Industry Need More Attention, Technical paper from Oil and Natural Gas Corporation Limited, February 2003 2. Keranl, M., Harrop, D.; The Impact of Corrosion on the Oil and Gas Industry, SPE, Production and Facilities, August 1996 3. Tomasz Szary.; The Finite Element Method Analysis for Assessing the Remaining Strength of Corroded Oil Field Casing and Tubing, Dissertation paper from Freiberg University, September 2006. 4. Mok Chek Min.; An Introduction to Corrosion, CMM NDT Services, 2008 5. https://octane.nmt.edu/waterquality/corrosion/corrosion.htm 6. https://www.materialsinspectionassociates.com/CO2.php 7. https://corrosion.ksc.nasa.gov/faticor.htm 8. Scoppio, L.; Assessment of Corrosion and Environmental Cracking of Metallic Materials in HPHTCs/K Formate Brines. 3rd Annual ChemiMetallurgyTM Technical Symposium, November 2007 9. https://www.imoa.info/moly_uses/moly_grade_alloy_steels_irons/oil_country_tubular_goods.html 10. J.A. Straatmann, A.P. Grobner. Molybdenum containing steels for Gas and Oil Industry Applications. Climax Molybdenum Company, 1978. 11. Dishimaru et al. in JFE Technical Report No.2, (Mar 2004) 12. Hashizume, Shuji. Materials selection in Oil and Gas Production. Tenaris NKKTubes, January 2008 13. https://www.sumitomo-tubulars.com/materials/index.htm 14. Technical Memorandum Gemite Products Inc, Corrosion of Steel in Concrete due to Carbonation. 22 April 2005 15. George V.Chilingar, Ryan Mourhatch, Ghazi Al-Qahtani. The Fundamentals of Corrosion and Scaling. Gulf Publishing Company. 2008 16. A. Turnbull, D. Coleman, A. J. Griffiths, P. E. Francis and L. Orkney, Effectiveness of Corrosion Inhibitors in Retarding the Rate of Propagation of Localized Corrosion, Corrosion, Vol. 59, No. 3, 2003, pp. 250-257. 17. https://www.cosasco.com/ 18. Ha-Won Song, Velu Saraswathy, Corrosion Monitoring of Reinforced Concrete Structures A Review, International Journal of Electrochemical science, 2007. Appendix A.1 Input parameters A.1.1 Basic input parameters The basic input parameters for the CO2 corrosion model for carbon steel are given in Table A.1.1. The allowed units and ranges are also given Table A.1.1 Basic Input Parameters Parameter Units Range Comments Temperature C 5 to 150 F 68 to 302 Total mass flow kmole/h 10-3 to 106 Only relevant when CO2 is given in kmole/h. CO2 fugacity in the gas phase bar 0,1 to 10 The CO2 partial pressure shall be psi 1,45 to 145 the total pressure. mole% variable The allowed ranges of mole% and kmole/h CO2 are dependent on the kmole/h variable total pressure. Wall shear stress Pa Can be calculated by use of other input parameters pH 3,5 to 6,5 Can be calculated by use of other input parameters A.1.2 Input parameters for wall shear stress calculations Wall shear stress is one of the parameters needed for calculation of corrosion rate. In the model, the mean wall shear stress in straight pipe sections is used. Obstacles and other geometrical changes in the flow will give rise to higher shear stresses than calculated by this program. Further, different flow regimes and geometrical obstacles may generate shear stress fluctuations where the shear stress peaks may be considerably higher than the average shear stress. High shear stress may cause mesa attacks, with corrosion rates significantly higher than what is estimated by this computer program. It is not the objective of this computer program to cover all such eventualities, and the user of the program shall evaluate the flow effect in each system/part of a system based on expertise and available experience and documentation. The mean wall shear on the wall at medium to high superficial velocities of one or both of the liquid and gas velocities where the friction factor, f, can be expressed as: Mixture density, velocity and viscosity is expressed as: To calculate the wall shear stress, the input parameters given in Table A.1.2, are as a minimum required Table A.1.2 Input parameters for simplified calculation of wall shear stress Parameter Units Range Comments Temperature C 5 to 150 F 41 to 302 Total pressure bar 1 to 1000 psi 14,5 to 14500 Superficial liquid velocity/ m/s 0 to 20 Requirement: turbulent flow, i.e. Liquid flow Sm/d (depends on internal pipe diameter) Re 2300 Superficial gas velocity/ m/s 0 to 40 Requirement: turbulent flow, i.e. Gas flow MSm/d (depends on internal pipe diameter) Re 2300 Watercut, % 0 to 100 Internal pipe diameter mm All diameters Requirement: turbulent flow, i.e. Re 2300 For more accurate wall shear stress calculations, the input parameters given in Table A.1.3 should also be used. Table A.1.3 Input parameters for accurate calculation of wall shear stress Parameter Units Range Default value Roughness m 0 to 100 50 Compressibility 0,8 to 1 0,9 Specific gravity of gas relative to air 0,5 to 1 0,8 Water density, w kg/m 995 to 1050 1024 Oil density, o kg/m 600 to 1100 850 Gas density, w kg/m 1 to 1700 calculated Water viscosity, w cp 0,17 to 1,1 calculated N s/m 0,00017 to 0,0011 Oil viscosity, o cp 0,2 to 200 1,1 N s/m 0,0002 to 0,2 Gas viscosity, G cp 0,02 to 0,06 0,03 N s/m 0,00002 to 0,00006 Watercut at inversion point, c 0,3 to 0,9 0,5 Maximum relative liquid viscosity, relmax 1 to 100 7,06 A.2 Interface of Model A.3 Comparison corrosion rate using another experiment (Parametric Study of CO2/H2S Corrosion of Carbon Steel Used for Pipeline Application, G. S. DAS A. S. KHANNA, Corrosion Science Engineering Indian Institute of Technology Bombay, 2004)

AIDS 101 Essay - 2073 Words

Aids The Human Immunodeficiency Virus (HIV) is responsible for Acquired Immunodeficiency Syndrome (AIDS) and attacks the T-4 lymphocytes, which are a fundamental part of the immune system of man. As a result, reduces the responsiveness of the organism to cope with opportunistic infections caused by viruses, bacteria, protozoa, fungi and other microorganisms. At the moment in which the AIDS virus is spreading with frightening speed and very dangerous and that there is a collective concern about AIDS, we must cling to developing our greatest means of defense known so far, which is information. Although AIDS is deadly, it can be prevented, and in that sense we all have an obligation to be met by seeking and disseminating information. This†¦show more content†¦All the sexual practices are probably the most dangerous because the virus enters the body more easily for two reasons. During the penetration, the pressure exerted by the muscles of the anus, the penis is very large and invari ably causes irritations, skinned and disruptions of mucosa and penile tissue, allowing more easily access the HIV virus in the bloodstream. The anal mucosa has a high absorption power, which explains the existence of drugs in the form of suppository. For this reason that AIDS spread such as virulence among homosexuals, it was called as gay plague. â€Å"In case of insecure intercourse from anal, the receptive partner has maximum chances of getting infected with HIV if the inserter is HIV victim† (Gunawan Harinanto). Remember that anal intercourse is also practiced by heterosexuals and that female rectal mucosa has the same characteristics of male It is also vulnerable to penetration of the virus. During intercourse, the virus lodged in the vaginal fluid enters the male urethra, affecting the blood and infect humans. However, as the HIV virus reaches higher concentration in semen than in vaginal fluids, their transmission from infected men to women sound occurs more frequently . The virus, installed in the sperm, goes to the vaginal mucosa, entering the bloodstream and infecting the woman. This explains why the number of women with AIDS has increased significantly worldwide. It is anShow MoreRelatedThe Presence And Outbreak Of An Infectious Disease1176 Words   |  5 Pagespandemic that has had far reaching consequences is that of HIV (human immunodeficiency)/AIDS (acquired immune deficiency symptoms), which officially began in 1981 and since has taken the lives of over 39 million people worldwide (PBS). The HIV virus attacks one’s â€Å"T-cells,† which are vital to one’s immune system. Someone infected with the virus becomes increasingly susceptible to contracting infections (Immune System 101). People can contract the HIV virus through the following ways: in their mother’sRead MoreHiv/Aids1137 Words   |  5 PagesOver the years, HIV and AIDS has been a growing epidemic. More and more people are being diagnosed with these life-threatening viruses. HIV, which stands for human immunodeficiency virus, is a virus that attacks the body’s immune system. In other words, it interferes with the bodys ability to fight the org anisms that cause disease (â€Å"HIV/AIDS,† 2014). AIDS, which stands for acquired immunodeficiency syndrome, is the last stage of HIV infection. Like in the name, AIDS is acquired; meaning it is notRead MoreEssay on Epidemiology and Communicable Diseases: HIV1281 Words   |  6 Pagescells or T cells. HIV attacks these cells and copies or replicates itself inside these cells, then destroys them. HIV over time will destroy so many of these cells that the body is unable to fight off infection anymore. When this starts happening, AIDS or Acquired Immunodeficiency Syndrome happens which is the final stage of HIV. HIV is transmitted through someones blood or bodily fluids which can encompass semen, breast milk, vaginal fluids, and rectal mucous (AIDS.GOV, 2013) and usually it isRead MoreA Closer Look at HIV Essay1145 Words   |  5 Pagesguidelines to help prevent the spread of H.I.V and other possible diseases. H.I.V symptoms have three stages. The first stage is referred to the as the Early Stage, next there is the Clinical Latency Stage, and finally there is the Progression to AIDs. During the Early Stage symptoms resemble that of a bad case of the flu. These symptoms include fever, tiredness, aches and pains, even a sore throat. There is no set duration of these symptoms. For some people symptoms may last a few days, for othersRead MoreChina s National Strategy Of Hiv / Aids Prevention Programs1346 Words   |  6 Pagesnational strategy of HIV/AIDS prevention, the group of men who have sex with men (MSM) has attracted much attention in the latest decade. In the year 2008, the Ministry of Health officially announced that gay men would be one of the targeted groups in HIV/AIDS prevention programs, as part of its national health initiatives[[1] AFP (2008, February 20) China launches first anti-AIDS drive for gay men: state media. Retrieved September 21,2015, from http://www.avert.org/hiv-aids-china.htm#footnote51_2gjd2tgRead MoreAIDS and HIV Essay1520 Words   |  7 Pages key cells of the immune system, and uses them to make copies of itself. After being infected with the virus it progressively interferes and eventually destroys the immune systems ability to fight the anti-genes. HIV may develop into the syndrome AIDS, the Acquired Immunodeficiency Syndrome. HIV is an STD - a sexually transmitted disease - and therefore most commonly it is spread through sexual contact, and the virus mainly enters the body through the penis, mouth, lining of the vagina or vulvaRead MoreHiv : A Modern Atlantian Epidemic1725 Words   |  7 Pagesa greater percentage of African-American residents and behaviors that increase the risk of HIV, including unsafe gay sex and injection drug use. Approximately half of newly diagnosed HIV patients in Atlanta have unknowingly progressed to full-blown AIDS, according to testing conducted by Grady Hospital (Archer, 2015 ). A disquieting amount of those patients, approximately 8%, reside within the same 30303 zip code as the hospital itself (Archer, 2015). According to the CDC more than 1.2 million peopleRead MoreAids : How It s Spread1023 Words   |  5 PagesStakely 1 Alex Stakely Professor Wheeler English 101-A (8:00 a.m.) 14 November 2014 AIDS: How It’s Spread AIDS is one of many outbreak diseases that have hit the U.S. It has spread all over the world and has been a major epidemic to our society. The disease started in the U.S. in the 1980s and has spread all over the states. AIDS is spread from person to person by unsafe sex, blood, and a mother’s birth milk because it is one of many transmittable diseases. You cannot get it from kissing, huggingRead MoreThe Effects of HIV754 Words   |  3 PagesAccording to the NYC Department of Health and Mental Hygiene, The Bronx has the highest HIV infection rate in New York City. In 2013, NYC.gov reported 35,172 people were living with HIV/AIDS in the Bronx. Acquired immunodeficiency Syndrome (AIDS) is the disease caused by the Human Immunodeficiency Virus (HIV), which is the final stage of HIV. This is a world wide epidemic, especially because most people living with HIV dont have access to prevention, care or treatment and there is still no cureRead MorePoverty, Education, Sanitation , Malnutrition, And Child Mortality900 Words   |  4 Pagesbit sluggish at 8% in poorer areas. The infant mortality is twice other Latin American countries. Live infant deaths are at 31.2, down from 72.2 in 1995 (UNICEF, 2015). Mortality for children under five is 39 out of 1000. This is a decrease from 101 out of a 1000 in the year 1995. Millennium Goals Although there have been many hindrances the goal of, eradicate extreme poverty and hunger, there has been some movement (United Nations, 2015). Globally malnourished has fallen by about half. One

Controversial Topics- Beauty Pageants Free Essays

Her eyes glimmer with the latest layer of eyeliner. Her cheeks, a wind-bitten pink, ache from constant smiles. She combs her hair, unaware of the damage she is inflicting on herself. We will write a custom essay sample on Controversial Topics- Beauty Pageants or any similar topic only for you Order Now She looks around. Some wear false hair, others false teeth. Every participant there is driven by the same potential outcome of beauty: meticulous hair, white smile, bright eyes, and a thin figure. Everybody strives for that same superficial facade – not the average values for a 5-year-old-girl.Since 1921 beauty pageants have been the roots of society’s delusive portrayal of beauty and until they are stopped, they will continue to cause detrimental impacts on a female’s perception of her self worth. Pageants began as a marketing tool for an Atlantic City hotel in 1921. They decided to hold a fall festival to tempt Summer tourists to stay past labor day. Every year, this pageant, Miss America, grew as America’s only pageant. However, in 1950, controversy arose: a contestant, Yolande Betbeze, refused to pose in a swimsuit.When the officials honored her preference, Catalina Swimwear discontinued their sponsorship and established the sexier, â€Å"Miss USA† and â€Å"Miss Universe† pageants. Since then, more major pageants have been established throughout the world. These include â€Å"America’s Junior Miss†, â€Å"Little Miss America†, â€Å"Miss Teen All America†, â€Å"Mrs. America†, â€Å"Miss T. E. E. N. †, â€Å"Miss. Teenage America†, â€Å"Mrs. World†, â€Å"Miss Black USA†, â€Å"Miss International†, â€Å"Miss Teen of America†, and â€Å"Miss Black USA Talented Teen†. However, these have not been supported by all. In 1968, The Women’s Liberation Front protested the Miss America pageant, infiltrating the main hall. Even while the pageants were launched purely as a marketing tool, they have taken a turn against natural beauty. Beauty is defined as something that brings pleasure to the senses (Define). This does not imply a symmetrical face, a curvy figure, or a ski-slope nose. Pageant judging is greatly impacted by these traits. However, nobody has the power to control what physical traits they have. Physically attractive people are the children of genetics, not personal drive, determination, or hard-work that is detrimental in life situations; but Sabra Johnson, a ten-year-old, veteran child contestant, doesn’t think so.A common aspiration of contestants is landing a major modeling career, and until then, modeling at the pageants. While interviewed by AE Network, she constantly looked over at her mom for reassurance of her thoughts. She never mentioned her future education; she relied solely on her appearance for her future (Children). She is missing out on many important opportunities. Intelligence for example, a person can work hard and do well on an exam, but while in beauty pageants, only the winners of the â€Å"social lottery† emerge victorious.Ones appearance has no correlation to ambition, drive, or personal discipline. Although these traits sculpt a beautiful person, most contestants are under the impression that beauty is achievable. They are under the impression that anorexia, bulimia, spray tans, fake hair, fake nails, removable eyelashes, plastic surgery, layers of make-up, or any combination will make them appealing. This idea starts at an early age. The television show, Toddlers Tiaras, follows several young contestants begin their pageant career. The overzealous mothers carve their daughters into miniature pageant stars.Overall, their mothers will deflect any interference to guarantee their daughters consummation. When young children have lost or crooked teeth, their mothers are notorious for attaining a â€Å"flipper†, a set of false teeth to go over their child’s’ natural set. If they have teeth, parents purchase whitening treatments. These ideals have a large impact on their present as well. A study conducted four years ago by NPD Group showed that women started using cosmetics at an average age of 17. Now this age has moved to an average of 13 (Toddlers).What these girls learn as children will sustain their adult years; they absorb the only method of being beautiful that is shown, and that is all they will ever know. William Pinsof, a clinical psychologist and president of the Family Institute at Northwestern University says, â€Å"Being a little Barbie doll says your body has to be a certain way and your hair has to be a certain way. In girls particularly, this can unleash a whole complex of destructive self-experiences that can lead to eating disorders and all kinds of body distortions in terms of body image† (Children).Currently, 15% of young women in America have some type of eating disorder (Eating). Some grow up with the idea that the thinner they are, the more attractive they are. This can lead to unfortunate interpretations of their body. In order to fulfill their perception of the ideal figure, they dangerously push boundaries; 50% of girls 8 to 10 years old say they are unhappy with their size, 40% of fourth graders admit to previously being on a diet, and more than 50% of girls 9 to 15 years old have exercised to lose weight (Pulling).Only to reward their behavior, the judges of the pageants asses the contestant’s physical appearance based on these superficial themes. The past winners are no role models either. The majority of Miss America winners have been ‘undernourished’ on the BMI scale, or Body Mass Index, a relation of someones height to their weight. Beauty role models are setting a poor example of how they should be taking care of themselves: Miss America 2008 is a recovering anorexic (Huey). As adults, they will consider superficiality the only way to be classified as admirable. A study done shows that Childhood pageant participants develop â€Å"a greater body dissatisfaction, an interpersonal distrust, and impulse deregulation than non-participants, and were ultimately ineffective† (Childhood). Because of all the scrutiny about their bodies, many young girls will ruin their future and their well being. Superficiality does not only impact the future sanity of pageant girls, but their safety, from their health to being victims. The children who participate in beauty pageants are often scarred by the experience.Dressing children in adult clothes and makeup appeals to sexual predators, creating a risk of becoming a victim of a pedophile. By definition, this is child abuse; from the Child Abuse Prevention and Treatment Act, child abuse is, â€Å"a failure to act on the part of a parent or caretaker, which results in death, serious physical or emotional harm, sexual abuse or exploitation, or an act or failure to act which presents an imminent risk of ser ious harm† (Child). Because there are no rules concerning promoters, organizers, and participants, pageants are exempt from laws governing them. Organizers want to earn money and are not concerned with the need to protect their participants. People believe that JonBenet Ramsey, a child pageant contestant, was murdered at the age of 6 because of her participation on pageants. Her parents put her in harms way by subjecting her to exploitation at pageants. Some parents are so misshapen, so attention-starved, that they will shamelessly exploit their child’s physical appearance with no regard for the potential consequences. Sexual predators are merely a tooth on the comb of pageantry concerns.Supporters of beauty pageants claim that participants develop confidence, self-esteem, and poise. This might be true, but that is not all they gain. Eating disorders, depression, and other life-altering issues can also be a side effect. 90% of 14-15 year-olds say they suffer depression produced by the pressure to look good (Beauty). Also, beauty pageants are breeding grounds for low self-esteem. This low self-worth can potentially introduce harmful situations: Children with low self esteem are 1. times more likely to be drug dependent nine years later than children with average self esteem (20); 70% of girls ages 15 to 17 avoid average daily activities such as attending school, going to the doctor, or giving their opinion due to their so called â€Å"looks† (Girl). Supporters of pageants also say that they are applauding and celebrating beauty, not patronizing it. If a celebration of all-around equality and beauty were being celebrated, there would be no winner. Instead, they take beautiful girls, line them up head-to-head against one another, and choose who is most attractive.Furthermore, supporters argue that judging beauty is as ethical as judging intelligence. Intelligence is obtainable through hard work and discipline; beauty is not. Nobody can change what they were born with, but they can change the way they think. The depth of knowledge is supported by the motivation to learn, while beauty is based on genetics. Nobody deserves recognition for originating from an attractive gene pool. Pageants seize every opportunity for judging on looks; they send a misinformed message to the public and to its participants that detrimentally impact society. Beauty pageants have, and always will, prove society’s delusive portrayal of beauty and until they are stopped, they will chip away at woman’s perception of their self-worth. No matter how old a participant is, whether 3 or 30, they will always misunderstand what real beauty is. How to cite Controversial Topics- Beauty Pageants, Papers