bluuebunny/crossref_metadata_2025 huggingface dataset:
Multi-Faceted Approach for Optimizing a Microbial Control Program
Authors: Keasler Victor , Bennett Brian , Keller Carrie , Kuijvenhoven Cor , Mahon Tom , James Stewart
Published: May 2012

Microorganisms are a major challenge for the petroleum industry and can lead to microbiologically influenced corrosion (MIC), reservoir souring, or biofouling. Typically used standard methods for microbial identification (i.e. MPN) have limited success at identifying problematic organisms and providing timely feedback. Consequently, it is important to develop a multi-faceted approach that provides faster and more insightful results on the risk of microbial difficulties.

A three-part approach was developed and implemented at Shell's Ursa platform to understand whether recent failures on the production system were the result of MIC and the efficiency of the biocontrol strategy on the recently installed waterflood to prevent system failure and reservoir souring. The approach involved 2nd generation ATP quantification for rapid enumeration of actively-growing microorganisms, as well as microbial enumeration and speciation using molecular methods.

Recent failures on the production system were believed to be the result of under-deposit corrosion and microbial attack. However, culture-based methods revealed low numbers of problematic microbes, suggesting that the failures were not from MIC. Using ATP quantification, the presence of active microbes was observed at the manifolds and shown to increase throughout the production system. Speciation and enumeration results confirmed that problematic microorganisms were present and this additional information allowed for identification of optimized treatment locations in the production system to minimize the risk of MIC.

For the waterflood, the new microbial analysis approach confirmed that the biocide program is successfully minimizing the risk of fouling, equipment failure and reservoir souring. ATP testing revealed occasional locations of elevated microbial growth and their potential for downstream contamination, allowing for further optimization, but overall demonstrated the biocide regime to be effective. The success of the biocide regime was determined by a reduction in active microorganisms and a population shift to Bacteria that are not likely to contribute to reservoir souring.

This audit revealed a clear understanding of the microbial risks at Ursa, including areas that were performing well and those that needed required changes. This process is an excellent tool for microbial risk identification and biocide program optimization.
Development of Double Layer Metal Thermal Spray: Novel External Corrosion Mitigation Method for Gas Well Tubing
Authors: Li Qiongwei , Yang Quan'an , Dong Xiaohuan , Li Mingxing , Xi Yuntao
Published: May 2012

This paper discussed the corrosion characters and new double layers metal thermal spary technology for gas well tubing in Erdos basin, Changqing field. Some gas wells produce formation brine, also contain low H2S content and medium CO2 content. (water/gas ratio lager than 0.2m3/104m3, and averge total ions strength is 120g/L, Cl− nearly 80g/L). The electric-chemical corrosion causes the workover lifetime of gas well less than 5 years.

On the external surface of SSC-resistant carbon steel (80S) tubing, the double metals protection layers of 13Cr and Aluminum were designed and applied by high speed arc spary technology. Physical and corrosive properties were researched at simulation and HT/HP conditions.

More than 15 wells were applied by this method in recently 4 years. Before workovering, the lifetime of those wells were not more than 5 years, also lower than regulation workover time of 8 years. At 4 years ago, the corrosion situations of 3 wells which would be workovered were inspected using the multifinger imaging tool and magnetic thickness tool, MID-K logging equipments. By now, those wells were logged (MIT+MTT) again and showing a good condition.
Pitting Behaviour of Lean Duplex Stainless Steels in Marine and Oilfield Environments
Authors: Aribo Sunday , Neville Anne , Hu Xinming
Published: May 2012

Lean Duplex stainless steels are becoming attractive for applications in oilfield and marine environments due to their economic advantages, very good mechanical properties and relatively good corrosion resistance. However, there is little information about the pitting behaviour of lean Duplex stainless steels in oilfield and marine environments. This paper discusses the tendency for pitting corrosion to initiate through an evaluation of breakdown potentials of lean Duplex stainless steels UNS S32101, UNS S32304, LDX2404, standard Duplex stainless steel UNS S32205 and Austenitic stainless steels, 304L and 316L in aerated 3.5% NaCl and a CO2-saturated oilfield brine solution. Electrochemical measurements were made using a three-electrode electrochemical set up using an Ag/AgCl reference electrode and a platinum counter electrode. The results showed that breakdown potentials are generally higher in aerated 3.5% NaCl than the CO2-saturated oilfield brine solution for all the alloys tested. Lean Duplex stainless steel UNS S32101 and Austenitic stainless steel 304L showed comparable breakdown potentials in both environments while lean Duplex stainless steel UNS S32304 and Austenitic stainless steel 316L also have comparable breakdown potentials. There does not seem to be a universal relationship between Pitting Resistant Equivalent number and breakdown potential for the lean Duplex and Austenitic stainless steels.
Performance of Synthesized Amine-based Corrosion Inhibitors in Concentrated HCl Acid Solutions: Effect of Intensifier
Authors: Al-Taq A. A. , Ali S. A. , Haji H. H. , Saleem J. A. , Al-Ibrahim H. A.
Published: May 2012

Mono and diamine compounds were synthesized from 1, 12-dodecanediamaine, and evaluated as acid corrosion inhibitors for coiled tubing steel. The inhibition behavior of these compounds in concentrated HCl acid was examined using a gravimetric method. Weight loss tests were conducted in 28 wt% HCl acid at 60, 70 and 80°C for 2 hours. The results showed that both mono and diamine inhibitors exhibited a good protection efficiency for coiled tubing steel in 28 wt% HCl acid. However, monoamine compounds showed better performance. Addition of an intensifier was effective to enhance protection efficiency for both amine moiety compounds where more than 99% protection was obtained for some inhibitors. The effect of intensifier concentration on inhibition efficiency is also addressed in this paper. The results obtained are very promising and suggest that some of examined corrosion inhibitors have a good potential to be used in acid stimulation treatments of oil/gas wells.
Superior High-Strength Drill Pipe Adopted in Harsh Environment
Authors: Inoue Tomoya , Kyo Masanori , Miyazaki Tsuyoshi , Sakura Koji , Fukui Toshikiko
Published: May 2012

S150 drill pipe was developed during construction of the scientific drilling vessel Chikyu, and has been used in the past scientific drillings. On the other hand, during past drillings, Chikyu faced harsh environments such as a high-current or a corrosive environment in addition to deep drilling. To reach deep drilling in such a harsh environment, a higher strength and reliability drill pipe, as well as strength evaluation using the high-strength drill pipe, is necessary.

Superior high-strength drill pipes, S155 and S160, possessing high reliability, such as corrosion resistance, have been developed. Pitting corrosion resistance, which causes stress concentration, is required to prevent fatigue failure. Also, consideration on possibility of SSC under low temperature at seabed is required because it would be a cause of fatigue.

Regarding deep drilling and extended reach drilling, required feature is fatigue resistance of not only pipe body but also tool joints. In particular, the tool joint starts to become the cause of wearing out, mud pressure loss, mud bedding, heat cracking, and failure itself.

The concept of the high-strength drill pipe, which we have developed, achieves high toughness and reduction of stress concentration along full string in the salt water to eliminate elements of fatigue phenomenon. The development includes the pipe manufacture process such as welding line performance, heat treatment methodology, the experimental investigation such as fatigue tests under salt water with or without pitting, and analytical investigation.

The superior high-strength drill pipes described in the paper possess not only the high-strength performance but also high fatigue resistance in the corrosive environment. These can exercise the potential capability in the deep drillings, extended reach drillings, and harsh environment drillings.
Investigation Self Healing Property of Cerium Nitrate in Organosilane Pretreated Anti Corrosion Coatings
Authors: Zaferani Sadeq Hooshmand , Peikari Mahmood , Zaarei Davood , Danaei Iman , Fakhraei Mohammad javad
Published: May 2012

The barrier property and self healing behavior of the coating systems containg organosilane and epoxy was investigated. The organosiolane componenet of coatings was doped with cerium nitrate and applied on cold rolled carbon steel substrates. Electrochemical impedance spectroscopy (EIS) and immersion tests were used for assessment of corrosion resistrance behaviour of coatings. Also SEM and EDS techniques were employed to investigate the self healing ability of cerium nitrate. Addition of 2 wt. % of cerium nitrate into the coating solution led to superiour self-healing property for scribed coating systems. Furthermore healing mechanism of cerium nitrate pigments was explained in detail.
MIC Risk Assessment of the Halfdan Oil Export Spool
Authors: Skovhus Torben Lund , Holmkvist Lars , Andersen Kenneth , Pedersen Heidi , Larsen Jan
Published: May 2012

Monitoring of Microbiologically Influenced Corrosion (MIC) in the oil industry has in the past been conducted mainly on sulfate-reducing bacteria (SRB) using cultivation based techniques. However, with the introduction of novel DNA-based methods for enumeration of microbes, more accurate and fast methods are now available which offer better determination of MIC on a routine basis.

The content of produced water in the Halfdan oil system during production is relatively low (BS&W < 1–2%) and MIC has for this reason not been considered to be a threat to the system integrity. Initial results from wall thickness inspection of oil export spools have indicated on-going corrosion. As a consequence, spools have been replaced, enabling sampling of cut-out sections of the spools. These cut-out sections have been sent onshore to DTI Oil & Gas for further investigation of general corrosion, MIC and scale composition.

The investigation demonstrated that the analysed Halfdan oil export spool sections were highly corroded. This conclusion was based on visual inspection of the metal surfaces of the cut-out sections that revealed presence of under-deposit and pitting corrosion underneath thick layers of solid scale material. In support of the visual indications of corrosion, it was demonstrated that MIC related microorganisms were present in the solids in close contact with the metal surface together with corrosion products. In particular, high numbers of the hydrogen consuming methanogens (108–109 cells g−1) were situated in the scale directly in contact with the carbon steel pipe wall. These important findings could only be achieved when results obtained from X-Ray analysis (WDXRF) and visual inspections of the oil export spools were combined with DNA-based enumeration methods (qPCR).

Based on the obtained results, this paper discusses how microbial numbers obtained from DNA-based enumeration methods are evaluated and interpreted in the best way with respect to general risk assessment and system integrity measures of aging offshore assets in the Danish Sector of the North Sea.
Injection Seawater versus Produced Water SRB and Archaea Populations in Oilfield Systems
Authors: Hoffmann Heike , Spark Iain
Published: May 2012

Seawater Injection is an essential procedure in many offshore facilities in the North Sea. This water passes through a variety of different treatments and environments. It is chlorinated, filtered, deoxygenated and treated with biocide and other chemicals. The water is then injected into reservoirs under high pressure and sometimes high temperatures, to eventually (after months or years) break through into the production system, where it is subject to various different temperature environments.

Microorganisms react rapidly to changes in their environment, particularly temperature and salinity; given their short generation times, the effects on the microbial population can be pronounced. The objective of this study was to characterise the microbial communities entering and leaving the reservoir with particular emphasis on sulfate-reducing bacteria (SRB) and Archaea, which are believed to be the major cause of microbiologically-influenced corrosion (MIC).

Denaturing gradient gel electrophoresis (DGGE) and fluorescence in situ hybridisation (FISH) were applied to sessile and planktonic samples collected from a number of North Sea seawater injection and production systems to compile a database of the microbial communities found in these systems. The FISH data were compared, to determine common traits and gross differences between topside seawater and production equipment locations. Additionally, the counts of SRB/ Archaea types were assessed and consideration was given to how these may influence the risk of MIC. DGGE data was used to track certain organisms through the systems to find commonalities; primarily, if there were any relationship exists between biofilm communities at different locations in the two systems.

The results indicate that there are similarities as well as subtle differences between the two systems and these are discussed in detail in this paper.
Micelle Detection for Optimising Corrosion Inhibitor Dose on an Offshore Platform
Authors: Mackenzie Cameron , Perfect Emma
Published: May 2012

This paper builds on the evidence for the optimum dose of organic film-forming corrosion inhibitor (FCCI) being at the critical micelle concentration (CMC) of the surfactant components, and the concept of micelle detection as a tool for understanding the effectiveness of the inhibitor dose in the field, which has been presented previously. It extends the underlying principles from laboratory testing, to the rapid analysis of field fluids and explores the different results available from alternative instrumentation.

An inhibitor optimisation trial was undertaken on an offshore oil production platform for protection of a subsea pipeline used to tie back wells 10 miles from the platform. Two micelle detection devices were used, both primarily using fluorescence detection – a simple handheld device for offshore testing and a more complex device used for testing shipped samples in an onshore lab. Electrochemical corrosion monitoring was also used to analyse the produced fluids as the inhibitor dose was varied from zero to 200% of the estimated optimum dose.

Results were clouded by a number of operational issues outside the control of the experiment but interpretation of the whole suggested that the offshore portable micelle analysis was overcome by large quantities of dispersed oil which masked the optical process. However the onshore testing gave some promising results, demonstrating a correlation between increased micelle levels and high inhibitor dose and suggesting that the original dose was sub-optimal.

These experiments supported the need to use the more complex instrument to be able to detect micelles in very impure systems. Making and testing such a device suitable for field operations is now a priority.
Challenges of Integrity Management of Pipelines and Erosion Control in Sand Producing Wells
Authors: Shirazi S. A. , McLaury B. S. , Husen A. A. , Venkatesan K. , Nadeem A. , Hassaballa S. A.
Published: May 2012

Sand production in oil and gas wells is becoming an increasing problem for operators due to sand settling, under-deposit corrosion, and/or erosion especially in sub-sea environment. The paper describes application of ultrasonic (UT) pipe wall thickness measurements and erosion calculations in assessing integrity management of pipelines in a subsea gas producing field. The subsea gas wells were completed with downhole sand control because of the unconsolidated nature of the reservoir sands. The gravel pack completions were designed to stop sand but allow some fines production to prevent plugging of the gravel packs and screens and hence loss of productivity. Some solids production was therefore expected over the life of the fields. After some time when additional gas wells were brought online, higher than expected sand production was observed. Thus, operators commissioned sand erosion studies and conducted UT wall thickness measurements in 2008 and two years later to measure wall thickness of the Pipeline End Manifold (PLEM) and associated spool pieces subsea. The results in the paper include a comparison of wall thickness measurements conducted in several key areas. The results indicate wall thickness measurements conducted in 2010 for most of the measurement locations were similar to 2008 results except for several regions where the UT measurements were questionable based on erosion calculations. One major observation from UT measurements is that most measured wall thicknesses were less than the nominal wall thickness by 0.5 to 1.0 mm including sections where no flow was going through (no erosion/ corrosion) indicating absolute values of UT measurements can not be trusted with confidence unless calibrated subsea. Finally, the paper describes how UT measurements, erosion calculations, production controls and operation philosophy can be combined to maintain asset integrity and to control erosion of pipelines.
Implementation of Nitrate Treatment for Reservoir Souring Control: Complexities and Pitfalls
Authors: Stott James F.D.
Published: May 2012

The activity of sulfate-reducing bacteria (SRB) has long been a major concern in oilfield water systems and petroleum reservoirs because these microorganisms are one of the main causative agents of microbial-influenced corrosion (MIC) as well as reservoir souring.

Calcium nitrate and sodium nitrate treatments have gained popularity in recent years as alternatives or supplements to conventional biocide treatments. The object of these nitrate treatments is the suppression of SRB activity by the selective manipulation of indigenous bacteria.

The treatments have met with mixed success; in some cases SRB activity has been suppressed, whereas in other cases the treatment has failed. Cases where nitrate treatment has not been successful are less likely to be publicized than cases where the treatment has been deemed to be successful. There are also instances where nitrate treatment has been successful in suppression of SRB activity but has given rise to unacceptable increases in corrosion rates in water injection pipe-work.

In the experience of the author, nitrate treatments are rarely planned, trialed or implemented in a systematic manner, so as to maximize the chance of success and minimize unforeseen negative consequences. Based on practical examples from the author's experience and published information, this paper examines the most important factors that should be taken into account in methodical planning of trials and field-wide implementation of nitrate treatments, with particular reference to corrosion control.
Assessment of MIC in Carbon Steel Water Injection Pipelines
Authors: Comanescu Iulian , Taxen Claes , Melchers Robert E.
Published: May 2012

The present study compares corrosion mass loss and pit depth measurements on carbon steel corrosion coupons exposed under similar operating parameters, but with different biological consortia. One set of data were obtained from standard flush disc corrosion coupons used to monitor corrosion rates in a water injection pipeline on the North Sea continental shelf. The coupons were exposed on average for 6 months over 6 years operational time. These data are compared with published corrosion data of coupons exposed in abiotic district hot water systems from several power plants situated in Europe. The exposure time for these coupons was 9 months. Both systems were anoxic and in the same temperature range and are comparable. Observations regarding relationship between MIC and bacterial consortia, bacterial numbers and type, water quality and corrosion products are also made.

The corrosion rate of the water injection pipeline is approximately 10 times higher compared with the corrosion rate in the abiotic district hot water system. It is concluded that the increased corrosion on the carbon steel coupons in the early stage is caused by MIC. This is also supported by the chemical and biological information available for the pipelines. The results reported here constitute the first step of an overall study to improve the level of understanding of the bacterial contribution to the total corrosion rates of carbon steel in water injection flowlines.

Such understanding is expected to improve management and operational decision-making for practical control of corrosion in the field, by providing predictions of expected life time as a function of control of biotic consortia (e.g. through pigging, and biocide treatments). Further, it will facilitate decisions concerning choice of pipeline construction materials for future design.
Influence of Brine with Different Supersaturation Ratio on Corrosion Processes for Pipeline Material Carbon Steel X65, Scale Deposition and Performance of Combined Inhibitor
Authors: Ciolkowski M. , Neville A. , Hu X. , Mavredaki E. , Sanders L.
Published: May 2012

Corrosion and scale deposition are well known problems in pipelines. Corrosion control of carbon steel pipelines requires an understanding of the simultaneous occurrence of both processes. To date there have been few studies demonstrating the interactions between surface scale deposition and corrosion processes. Common methods of controlling corrosion and scale are deploying corrosion and scale inhibitors. However, combined (ComI) are receiving increased attention from industry as their application can significantly reduce chemical costs. Many factors influence the performance of corrosion and scale inhibitors and the influence of supersaturated brines on the surface scale deposition and subsequent effects on corrosion processes are generally not well understood. The work presented describes a range of laboratory tests conducted to assess the influence of different supersaturated brines on corrosion and scale on both inhibited (ComI) and uninhibited systems. Corrosion is measured by conventional electrochemical techniques and surface deposition is assessed using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX). Bulk precipitation is measured by turbidity.
Application of Chicory as Corrosion Inhibitor for Acidic Environment
Authors: Choudhary Yogesh Kumar , Sabhapondit Anupom , Kumar Arunesh
Published: May 2012

During acidizing stimulation or cleanup operations, metal tubulars, downhole tools/valves, surface lines, etc. are exposed to acidic fluids and are prone to corrosion. Because corrosion rates drastically increase in high-temperature wells, controlling corrosion is critical and must be dealt with carefully. In addition, corrosion protection is important for maintaining the integrity and long life of downhole tools installed in a well. Several corrosion inhibitors, such as quaternary ammonium compounds, propargyl alcohol-based compounds, etc., have been effectively used in the industry. However, because of stringent environmental regulations, attention has focused on the development of new corrosion inhibitors that are environmentally benign. Food-grade products that are considered "green" chemicals have significant potential as corrosion inhibitors in the oil and gas industry.

In this paper, application of chicory as a corrosion inhibitor for high-temperature and strong-acidic conditions is discussed. Chicory is a perennial bush plant available in many parts of the world. The root of the chicory plant can be roasted and ground for use as a coffee substitute or additive. Chicory is environmentally acceptable and, being of plant origin, is widely recognized as biodegradable in nature. This study shows that chicory can provide corrosion protection for alloys, such as N-80, 13Cr-L80, and 1010 steel, in the presence of either inorganic or organic acids at temperatures up to 250°F (121°C). Considering its good performance, low price, and no toxicity issues, chicory has significant potential for acid corrosion-inhibition applications. The mixing procedure for preparing the blend, experimental setup and test procedure, and laboratory results of high-pressure/high-temperature (HP/HT) corrosion tests are discussed.
Corrosion Inhibition Workflow Allows Injection of High-Volume Acid Treatments through Coiled Tubing Strings in Offshore Mexico
Authors: Martin Frederic , Miquilena Emilio , Molero Nestor , Acevo Ana Karina , Franco Ernesto , Garcia Martin Garcia , Castillo Marco
Published: May 2012

Since 2003, the main challenge of selective matrix treatments with coiled tubing (CT) has been to manage the severe corrosion rates of CT strings with large acid volumes and long exposure times to hydrochloric acid (HCl), resulting in reduced pipe life. Generally, the average volume required per job is 300 bbl of 15% to 20% HCl, depending on the bottomhole conditions and damage mechanisms; severe material losses of carbon steel coiled tubing string grade 90,000 psi have been regularly measured above 0.20 lb/ft2.

Our local stimulation team has developed an engineering workflow that consists of several stages and can reduce corrosion rates below 0.05 lb/ft2. A laboratory database was built to perform corrosion tests under time and temperature conditions and evaluate available corrosion inhibitors. The database allows the selection of the inhibitor and concentration range for each application. To reinforce the quality control, field preparation of acids is monitored and samples are tested to compare with laboratory design. Finally, measurements of coiled tubing wall thickness give an estimated value of material weight loss.

As a result of the implementation of the workflow, average pipe life has been extended from 1,200 to 3,000 bbl of 15% HCl pumped.
External Localised Corrosion of Offshore Topside Riser System
Authors: Anunobi Kingsley
Published: May 2012

Offshore risers are major assets for oil & gas operator as they represent a significant part of the cost of any offshore project and are relied to transport produced fluids. Furthermore, they represent major Health, Safety, or environmental threats to populations or the environment, if any significant leak or rupture occurs. Therefore any company operating hydrocarbon risers is required to implement rigorous external corrosion management strategy.

For an offshore riser installation, life cycle Riser Integrity Management is essential at design concept, FEED, detailed design, fabrication/construction, execution, commissioning, and operations to ensure the asset is fit for service throughout its service life. Riser external corrosion management is an important aspect of the overall riser integrity management during operation which includes operation preparation, inspection, maintenance and repair. In-service riser external corrosion inspections are to be planned to identify the actual conditions of risers for the purpose of integrity assessment to ensure structural reliability. The benefit of planning and executing maintenance and inspection activities simultaneously cannot be over emphasized.

This paper will describe some specific external localized corrosion issues frequently enencountered in the offshore oil and gas riser systems. The integrity implications and recommendations for addressing these issues both at the concept selection and Front End Engineering Design (FEED) stage as well as during in-service. The paper will also highlight the major benefit of using the correct mix of inspection techiques or tool based on the prior knowledge of the associated corrosion damage mechanisms and the benefit of an optimized preventive and corrective maintenance strategy in the overall life cycle Riser Integrity Management.
Acid Corrosion Inhibitors with Improved Environmental Profiles
Authors: Sitz Curtis , Frenier Wayne , Vallejo Connie
Published: May 2012

This paper discusses our successful efforts in developing new all oxygen based acid corrosion inhibitors that are biodegradable, non-bioaccumulating and low in toxicity, that meet industry standards for protection of carbon steel oilfield tubing up to 120°C (~250°F). These are environmentally acceptable inhibitors with the appropriate dispersibility and performance characteristics needed for critical applications in environmentally sensitive areas.

Matrix acidizing treatments are employed to remove reservoir damage by introducing acidic solutions (usually hydrochloric acid, HCl) into the formation at pressures below those used in fracturing operations. HCl is also used in acid fracturing as an alternative to proppant fracturing. The use of HCl requires that an effective acid corrosion inhibitor be included in the treatment package to protect the well's hardware.

Quaternary amines, including pyridine and quinoline quats, are frequently used as the active components in many corrosion inhibitors. While possessing excellent inhibition properties, the compounds are toxic to many forms of sea life, as well as to humans. Quats have been the backbone of the HCl acid corrosion control efforts for many years since they are very effective inhibitors and were often beneficial in improving the compatibility of the inhibitors with the HCl formulations. While oxygen based acid corrosion inhibitors are also in commercial use, they are usually formulated in conjunction with quats.

As environmental regulations become more stringent, some compounds are being banned or are listed for substitution. In the United States and Canada, producers and service companies alike are developing product standards to improve their portfolios in an effort to proactively address environmental concerns and to be responsible corporate citizens. Our efforts were focused on developing oxygen-based inhibitors that met or exceeded the current regulations and requirements established by various governments, producers and service companies. The target was to formulate an inhibitor that contained only environmentally acceptable components, and specifically excluding propargyl alcohol, pyridine and quinoline quats, US EPA Priority Pollutants, nonylphenol ethoxylates (NPE), BTEX, methanol, ethylene glycol and ethylene glycol monobutyl ether (EGMBE). Developing an all oxygen-based inhibitor proved to be quite challenging.
Sour Service Assessment for Aging Assets and Pipelines
Authors: Marsh Zeinab , Marsh Jonathan
Published: May 2012

One of the most problematic issues facing aging assets and pipelines in the offshore UK oil and gas industry is exposure to increasing levels of H2S. Increasing levels of H2S can occur due to a number of factors. H2S can be generated within pipelines or topsides facilities due to poor microbial control, leading to SRB activity. This can affect the facilities and pipelines themselves, and anything downstream. H2S can also be generated by field souring, where SRB contamination of the reservoir has occurred due to poor microbial control of injection water. Finally, assets that have produced sweet gas over the majority of their lives may become gas deficient, requiring gas import for start up, gas lift and fuel gas purposes. Even though these assets have been exporting sweet gas, the only gas that may be available for import may be sour. In all of these cases, the existing infrastructure may have been constructed for sweet or slightly sour service, and may now face exposure to sour environments beyond the original design criteria, or beyond the materials limits defined by ISO 15156. In such circumstances, or where a new operator is taking over operatorship of older assets, a sour service assessment of the facilities and pipelines is strongly recommended. This publication describes the sour service assessment process. It also describes the justification criteria for continued operation where materials are found to be non compliant, and the remedial actions required where a suitable justification cannot be put in place. It will also discuss the generic findings from assessments performed on a number of assets and pipelines in the UK sector, and examine in detail the assessments performed for the TAQA Bratani assets and pipelines.
Trichophagia and Trichobezoar: Case Report
Authors: Tiago Santos , Nuno Madeira , João Alcafache , Carla Vicente , Gonçalo Molinar , Joana Noronha
Published: May 2012

Objective:

Trichobezoar consists of a compact mass of hair occupying the gastric cavity to a various extent. When the trichobezoar extends past the duodenum it is better referred to as Rapunzel Syndrome. Although trichobezoars are well described in terms of surgical diagnostic and procedure, there are only but very scarce reports on psychiatric literature, usually associated with trichotillomania. The authors present a clinical case of trichobezoar and discuss the most relevant aspects concerning this entity.

Methods:

Presentation of psychiatric and surgical data concerning the case report. Previously reported cases are also mentioned.

Results:

Report of a 27-year-old female patient with a trichobezoar submitted to surgical removal, with a prior intervention 4 years before also due to trichobezoar, and with unknown psychiatric antecedents or follow-up.

Conclusions:

A trichobezoar represents a serious surgical condition. It is important to consider such diagnosis in face of suggestive symptoms, even if signs of trichotillomania are not present. The discrepancies between the prevalence of trichotillomania and trichobezoars due to trichophagia may be due to issues related to self-selection of patients and symptom severity. Such issues may also be important in the study of impulsive-compulsive spectrum models and to their relevance to impulse control disorders.
Nonlinear generalized contractions on Menger PM spaces
Authors: Babacev Natasa
Published: May 2012

This paper presents a fixed point theorem for a self-mapping defined on
probabilistic Menger spaces satisfying nonlinear generalized contractive
type conditions. The theorem is an improvement of a result presented by B.S.
Choudhury, K. Das: A new contraction principle in Menger spaces, Acta
Mathematica Sinica 24 (2008), 1379{1386. This is illustrated with an
example.
The influence of chemical reaction and viscous dissipation on unsteady MHD free convection flow past an exponentially accelerated vertical plate with variable surface conditions
Authors: Kishore P.M. , Bhanumathi D. , Verma Vijayakumar
Published: May 2012

A numerical study is presented on the effects of chemical reaction and
magnetic field on the unsteady free convection flow, heat and mass transfer
characteristics in a viscous, incompressible and electrically conducting
fluid past an exponentially accelerated vertical plate by taking into account
the heat due to viscous dissipation. The problem is governed by coupled
non-linear partial differential equations. The dimensionless equations of the
problem have been solved numerically by the implicit finite difference method
of Crank - Nicolson?s type. The effects of governing parameters on the flow
variables are discussed quantitatively with the aid of graphs for the flow
field, temperature field, concentration field, skin-friction, Nusselt number
and Sherwood number. It is found that under the influence of chemical
reaction, the flow velocity as well as concentration distributions reduce,
while the viscous dissipation parameter leads to increase the temperature.
Biological treatment of phenolic wastewater in an anaerobic continuous stirred tank reactor
Authors: Firozjaee Taghizade , Najafpour Ghasem , Asgari Ali , Khavarpour Maryam
Published: May 2012

In the present study, an anaerobic continuous stirred tank reactor (ACSTR)
with consortium of mixed culture was operated continuously for a period of
110 days. The experiments were performed with three different hydraulic
retention times and by varying initial phenol concentrations between 100 to
1000 mg/L. A maximum phenol removal was observed at a hydraulic retention
time (HRT) of 4 days, with an organic loading rate (OLR) of 170.86 mg/L.d. At
this condition, phenol removal rate of 89% was achieved. In addition, the
chemical oxygen demand (COD) removal corresponds to phenol removal.
Additional operating parameters such as pH, MLSS and biogas production rate
of the effluents were also measured. The present study provides valuable
information to design an anaerobic ACSTR reactor for the biodegradation of
phenolic wastewater.
Nicaraguans and the Educational Glass Ceiling in Costa Rica: The Stranger in Our Midst
Authors: Locke Steven , Ovando Carlos J.
Published: May 2012

This qualitative case study focused on the socio-cultural and educational experiences of undocumented (i.e. in the sense that they do not have the necessary documents to be in the country legally) Nicaraguan students in rural K-12 schools in Costa Rica. In this longitudinal study, a number of Nicaraguan students and their parents were interviewed during two different time periods over 11 years. The study was contextualized in the relatively new phenomenon of South-South immigration and revealed that immigrants maintained close connections with the communities they left and formed networks that supported new arrivals in Costa Rica. Despite blatant and overt discrimination, the students made significant educational and economic gains, which have moved them up the economic and social ladder. Eventually Nicaraguans hit a glass ceiling that limited their upward mobility and forced them to find alternative paths to achieve their goals.
‘For Them it's Sink or Swim’: Refugee Students and the Dynamics of Migration, and (Dis)Placement in School
Authors: Dávila Liv Thorstensson
Published: May 2012

This article focuses on qualitative research conducted with a group of refugee high school students from the Vietnamese Central Highlands living in the south-eastern region of the United States. As students with limited and/or interrupted formal education, they face linguistic, academic, and social challenges that confound their expectations for success in and beyond school. Analyzed through Bourdieu's theory of field (1977), the research shows that in spite of the students associating school with long-range aspirations, certain normative school structures and interactions prove detrimental to their language learning, their self-esteem and their motivation to succeed. The experiences of this group shed light on the education of newcomer high school refugee youth, building critical understanding for regions with growing linguistic and ethnic diversity. Possibilities for integrative linguistic and academic support for refugees with limited and/or interrupted formal education are discussed.
Between Aspiration and Achievement: Structure and Agency in Young Migrant Lives
Authors: Priyadharshini Esther , Watson Jacqueline
Published: May 2012

This article puts forward the argument that young migrants considering Higher and Further Education require robust structural support that attends to their psycho-social, communal, and material needs. Despite evidence of young migrants having high aspirations to achieve in this country, policy in the United Kingdom increasingly presents them with structural barriers rather than structures of support. This argument is based on findings from a recent research project which was conducted in the East Anglian region of the UK with children originally from central and eastern Europe. The children were all aged between 13–15 years and living in designated deprived areas. The article situates the project's findings in the context of the wider literature on aspirations in relation to education and employment, and examines the implications of recent UK government policy changes on the structures impacting on migrant youth's agency to achieve through Higher and Further Education. The authors suggest that migrant students are uncomfortably suspended in the gulf between desires and outcomes, with government policies failing to match the vibrancy of their agency to achieve.
‘School's Not for Anybody’: Migration as a Sponsor of Literacy in the USA—Mexico Context
Authors: Meyers Susan V.
Published: May 2012

In the USA–Mexico context, migration is often considered to be a detrimental influence on young peoples' pursuit of education. When migration is considered to be a positive influence, focus rests on the ways that increased financial resources can create more access to formal education in the migrant's home community. Indeed, physical access to schools tends to be the focus of many initiatives to improve educational experiences in developing nations, or among groups of minority students within the USA. Beyond these considerations of economics and access however, the potentially positive social impacts of migration are rarely considered. Drawing on a year of field data in rural, migrant-sending Mexico and a receiving community in the USA, this article argues that migration actually facilitates, rather than jeopardizes, educational gains in both Mexico and the USA. In particular, social capital garnered through the migration experience and transferred in the form of social remittances, as opposed to purely financial remittances, can have a particularly strong impact on literacy. Furthermore, the ideological impact that these social remittances can have on migrating populations may in some cases have a more powerful effect than does physical access to schools.
Educative Assimilation as a Process of Exclusion: The Case of Immigrant Students and ATALs in Cadiz, Spain
Authors: Gámez Rafael A. Jiménez , García Mayka García , García Manuel Cotrina
Published: May 2012

There has been a significant increase in the number of immigrant students in Spain, particularly in the region of Andalusia. However, some of them do not speak Spanish (which is the language of instruction used to teach the core curriculum) and this situation has led the regional government to create language adaptation classes (Aulas Temporales de Adaptación Lingüística [ATALs]) at primary schools. This article examines some aspects of a research study on cultural diversity, and presents the main inconsistencies arising from the setting of the ATAL programme. These inconsistencies are related to power issues that underlie intercultural education. The model of intercultural education promoted by the programme is discussed. The ATAL programme warrants consideration, since it may in fact be an instrument that consolidates the status quo, and may place immigrant students in a disadvantaged position.
Addressing the ‘Citizenship Assumption’ in Critical Pedagogy: Exploring the Case of Rejected Female Sub-Saharan African Asylum Seekers in Malta
Authors: Pisani Maria
Published: May 2012

The degree to which an individual can or cannot confront domination is determined by his or her place within the social relations of production, the hegemony of ideological beliefs, including patriarchy and other cultural constructions, and institutional rules, regulations, and practices. These interactions are also shaped by the ways in which members of specific social groups understand, perceive, and act in, through, and on, their reality. This article considers the Maltese context, and the case of sub-Saharan African (SSA) female asylum seekers whose request for asylum has been rejected. The article aims to provoke a critical re-evaluation of the adult education and critical pedagogy literature, and calls for an epistemological shift in the way we theorise the non-citizen within the nation state. The article argues that the ‘rejected’ status limits the possibilities to speak unto power and to mobilise for transformative change. It concludes that a ‘statist’ hegemony is ubiquitous within critical pedagogy literature, wherein ‘citizenship’ is assumed.
(Not) Leaving Turkmenistan? A Survey of Students from Turkmenistan at the American University of Central Asia
Authors: Stonawski Rebecca L.
Published: May 2012

University students from Turkmenistan find it increasingly difficult to study in their native country. As one option, some have traveled to the American University of Central Asia (AUCA) in Kyrgyzstan. However, due to a Turkmen government policy implemented in the fall of 2009, their opportunities to study in Kyrgyzstan are now even more restricted. The author anonymously surveyed 22 AUCA students from Turkmenistan in the spring of 2009. From varying ethnic backgrounds, they offered their opinions on educational opportunities in Turkmenistan, a potential return to Turkmenistan after their education, their perceptions of ethnocentrism within Turkmenistan, and the outlook for ethnic minorities in Turkmenistan in the future. This very limited sample means that quantitative analysis of the data is limited. However, it does provide a starting point for future research on education policy in Turkmenistan, specifically in relation to how policy on international education is impacting migratory populations, and how this is perceived by those most impacted by it.
Education and Citizenship: Redemption or Disempowerment? A Study of Portuguese-Speaking Migrant (and Non-Migrant) Youth in Portugal
Authors: Ribeiro Norberto , Almeida Carla Malafaia , Fernandes-Jesus Maria , Neves Tiago , Ferreira Pedro D. , Menezes Isabel
Published: May 2012

The institution of the European Union has had important implications on educational policies throughout Europe, with a growing emphasis on ‘Citizenship Education’ since the mid-1990s. This can be interpreted as a response to phenomena such as the rise of ethnocentrism and xenophobia and of political disaffection of both older and younger citizens. Departing from Weiler's notion of educational reform as compensatory legitimation, this article analyses the case of migrant youth in Portugal, which is particularly interesting for two reasons. The first is that migrant policies in Portugal have been extremely well evaluated by international agencies, in terms of their potential for the inclusion of migrants. The second is the fact that the migrant groups considered here, Angolans and Brazilians, both have Portuguese as their first language, hence not facing a ‘classical’ barrier to social inclusion. The research presents Portuguese data collected under the European project, Processes Influencing Democratic Ownership and Participation (PIDOP), and confronts the vision of policy makers, national and migrant youths, their parents, and their teachers. On the whole, results suggest that there is a huge gap between educational policy and the real life of schools that partly explains the (dis)empowerment of both migrant and national youth. However, in looking at this process, we must also recognise the complex role of generational factors, cultural capital, and political structures (both in the home and host contexts) in explaining youth civic and political engagement and participation.
The Challenge of Cultural Diversity in Greece: Reflections on ‘Intercultural Education Schools” (IES) Strategy for Creating Inclusive Learning Environments
Authors: Trouki Evie
Published: May 2012

With the aim of contributing to the discussion on the role of education in societies experiencing significant levels of migration, this article focuses on the ‘Intercultural Education Schools' (IES) established by the Greek State in 1996. Within a highly centralised educational system, IES were considered to be the answer to the need for educational and social integration of minority pupils, especially those who were immigrants. On the other hand, IES have been strongly criticised as marginalised school environments that have failed to manage diversity proactively. Drawing on different sources of data (e.g. interviews, questionnaires, school reports), this article attempts to illuminate the mission of IES, as well as their potential and constraints. The possible impact of IES on the formulation of appropriate strategies for combating educational and social exclusion is also discussed.