bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reliable & Efficient Feed Gas Preparation - A Key Enabler to Pearl GTL
Authors: Ramachandran Sakthivel , Engel Dico 
Published: May 2012

Abstract
In July 2006 the first stone was laid for constructing the largest Gas To Liquids (GTL) plant in the world, the Pearl GTL Complex in Ras Laffan, Qatar. After completing Shell's first GTL plant in Bintulu, Malaysia in 1993 with a debottlenecked capacity of 14 kbbl/d, the Pearl GTL plant is a major leap forward in size, innovation and integration. Pearl GTL is designed to produce 140 kbbl/d of finished GTL products and some 120 kbbl/d of natural gas liquids, including field condensate and ethane. Raw feed gas is routed from 2 identical offshore Platforms in the Qatar North Field via 2 parallel 30" subsea pipelines to the onshore GTL manufacturing complex.
The reliable, efficient and well integrated Feed Gas Preparation plant is a key enabler to the overall success of the Pearl GTL complex. Feed Gas Preparation includes offshore platforms, inlet receiving facilities, integrated gas treating units and NGL extraction/fractionation unit.
The design of the Feed Gas Preparation complex is based on Shell's years of experience in designing, building, licensing and operating many Gas Processing & LNG plants. Due to the highly integrated design, implementation of significant technology innovations was executed only after thorough analysis and issuing of formal development releases.
The Pearl GTL plant came into operation on 23rd March 2011. Stable production of sweet Natural Gas, Sulphur, Propane, Butane and Condensate at 40% design capacity was achieved within 10 days. The plant is meeting its design capacity and product quality, and complies with stringent environmental specifications. The innovative design approach used has resulted in a stable, reliable operation and has contributed to the sustainable development of the project.
This paper describes in detail the configuration of the Feed Gas Preparation plant in Pearl GTL and highlights the key features in the design, construction, commissioning and start-up experiences.
Development of Predictive Emission Monitoring System Algorithms for Qatargas Turbine
Authors: Suliono Andi , Sadois Claude , Raja Mohsin , Baldwin James 
Published: May 2012

Abstract
Qatargas Operating Company Limited (Qatargas) and Total Research Center Qatar (TRC-Q) established a collaboration to study Predictive Emissions Monitoring System (PEMS) algorithms for pilot application on a Qatargas turbine to predict NOx emissions. The approach for this Pilot Study was a blind benchmarking comparison of three main PEMS algorithms (first principle, statistical and neural networks) to define the most appropriate one(s) for application at the pilot gas turbine. This study was intended to demonstrate to local authorities that PEMS can be a reliable monitoring technique in both an alternative or complimentary capacity to CEMS.
The assessment of PEMS models developed as part of this study and their corresponding performance will be discussed in a separate paper when the study is completed. This initial paper describes the challenges and lessons learned during the preparatory phase of PEMS model development. It describes the importance of a well-planned preparatory stage as this significantly affects the quality and validity of collected turbine operational and emissions data for PEMS model construction.
It is important to undertake internal quality assurance checks on collected operational and monitored emissions data prior to model development. This paper describes the important role played by maintenance and calibration of measuring instruments such as stack emissions analyzers in ensuring reliability and accuracy of measured data. To build robust PEMS models, individual correlations between NOx emissions and various turbine operational parameters need to be assessed in the preparatory stage.
The PEMS models developed for the pilot turbine were initiated on an incremental basis using variables with significant correlation and then optimized using other secondary parameters to improve correlation between the predicted and measured NOx emissions. This paper notes that the influence of turbine operational parameter on NOx emissions varies depending on its role in the formation of NOx as part of the combustion process. These include fuel gas composition and flow rate, as well as ambient air temperature and humidity.
Thermal Stability of Various Chelates that are used in the Oilfield and Potential Damage Due to their Decomposition Products
Authors: Sokhanvarian Khatere , Nasr-El-Din H. A. , Wang Guanqun , De-Wolf C. A. 
Published: May 2012

Abstract
Chelating agents are used to remove various inorganic scales, including sulfates and carbonates. They are also used as stand-alone stimulation fluids and as iron control agents during acidizing treatments. The main chelating agents used in the field, include: ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), N-(hydroxyethyl)-ethylenediamineteriaacetic acid (HEDTA), and recently, L- glutamic acid-N, N diacetic acid (GLDA). One of the concerns with these chelates is their thermal stability at elevated temperatures. A few studies examined the thermal stability of these chelating agents, and the impact of thermal degradation products on permeability. The objectives of the present study are to: 1) Examine the thermal stability of several chelating agents and their salts up to 450°F, and 2) assess the effect of thermal decomposition products on the permeability of carbonate and sandstone cores with different initial permeabilities.
We prepared solutions (0.4 to 0.6 M) of HEDTA, GLDA, NTA, EDTA and their salts. The solutions of these chelates were heated at various temperatures and times (2 to 12 hrs.). The concentration of chelate was determined using a new analytical technique that was based on titration with FeCl3. The products of thermal decomposition of chelates were determined using MS technique.
Core flood tests were conducted on Berea sandstone and Indiana limestone to determine the effect of thermal degradation products on the permeability of these cores. Coreflood tests were conducted at 325°F and 3 cm3/min.
Most chelates decomposed at temperatures greater than 350°F. Among monovalent salts, potassium salt was found to be the most stable one. Chelates with two nitrogen atoms were more stable than those with one nitrogen atom. For example, diammonium salt of EDTA is more stable than diammonium salt of GLDA. Analyses of chelate solutions after heating using MS technique highlighted that the decomposition products included: iminodiacetic acid, formic acid, and α-hydroxy acids. Results of the coreflood indicated that some of the thermal decomposition products can cause formation damage. This paper will summarize the results obtained, and explain how chelates can be used to improve field treatments, especially at high temperatures.
Optimization of Limited Entry Matrix Acid Stimulations with Laboratory Testing and Treatment Pressure Matching
Authors: Van Domelen Mary S. , abd Hammoud Mohamad , Glasbergen Gerard , Talib Noor 
Published: May 2012

Abstract
In the Danish Central Graben, tight chalk reservoirs have been successfully developed through drilling, completion and stimulation of long horizontal wells. One of the most successful technologies which has opened access to the far reaches of several major fields is the Controlled Acid Jetting (CAJ) technique. CAJ treatments are performed with a treatment pressure at formation below fracturing pressure and at the maximum rate possible. Diversion is via maximum rate/pressure, combined with the limited entry technique; therefore diversion stages are not normally included in CAJ treatments. A horizontal CAJ completion may range from 5,000 ft to as long as 20,000 ft, but is most often on the order of 10,000 ft. Acid coverage is normally 1 bbl/ft of 15% HCl. Injection rates as high as 40-50 BPM are often required to ensure complete coverage of the CAJ liner.
There are still areas to be investigated to maintain an effective optimization of the CAJ technology. One of these areas to be investigated is the frictional pressure drop across the perforations (ΔPperf), which is influenced by the perforation coefficient (Cp). Usually in the design and operation of the stimulation, Cp is assigned a specific value when calculating the pressure drop across the perforations. Field experience and previous studies discovered that the Cp may change due to the viscosity of the fluid injected.
This paper will present the results of a study of the perforation coefficient through laboratory experiments. A set-up for measuring the pressure drop across an orifice for different types of fluids at different flow rates was constructed. The perforation pressure drops were measured and then used to calculate the fluid specific Cp in order to clarify any changes in relation to the viscosity.
The results of the laboratory study are utilized in a real-time CAJ stimulation diagnostic tool which has been used in several different chalk formations. The predicted acid coverage of the long CAJ liners is shown to be very sensitive to the assumed value of Cp. Overall, the outcome of this project was considered as a further contribution to the process of achieving a better understanding of the CAJ stimulation in general and about the impact of the perforation coefficient in specific.
The Impact of TAN from Heavy Oil EOR to Operation and Integrity: Case Study
Authors: Nengkoda Ardian 
Published: May 2012

Abstract
The reserve of conventional oil is decreasing as a trend and it is leading to the price hikes for conventional crude. Finding alternative energy sources including heavy oil is therefore a major agenda of the day. Thus there is an incentive to explore the heavy oil with a priority. One of the major issues dealing with heavy oil production is TAN (Total Acid Number) from crude oil. What is the impact of TAN to flow assurance? The value of crude oils is often dependent on the corrosivity of the oil, and corrosivity is mainly a function of the total acid number of the oil. TAN, in turn, is heavily dependent, although not completely so, on the naphthenic acid concentration of the oil. Consequently, crudes having a relatively high TAN, e.g., ≥2 have a significantly lower market value, on a per barrel basis, than crudes having a relatively lower TAN. The current approach to refine acidic crudes is to blend the acidic crudes with non-acidic crudes, so that the TAN of the blend is no higher than about 0.5. The case study have been conducted to predict the overall mix of crude TAN in main oil line and see the impact of TAN from heavy oil steam EOR operation in Oman. The workflow are covering: set up and define laboratory testing to see the root cause of TAN and the impact of heavy oil EOR crude to overall field, develop a worst case scenario and selecting the other alternative to lowering TAN. For example, the first basic strategy in managing TAN, high TAN crudes are often blended off with lower TAN crudes, the second strategy is to injecting some TAN reducing chemicals. Finally, the techno-economic matrix will help the decision of managing TAN.
The Design, Implementation and Use of Inflow Control Devices for Improving the Production Performance of Horizontal Wells
Authors: Minulina Polina , Al-Sharif Shahin , Zeito George , Bouchard Michel 
Published: May 2012

Abstract
The use of horizontal and multilateral wells in heterogeneous reservoirs has become well established over the last 10–15 years and has resulted in improved recovery and increased field life. Due to the non-uniform influx from these wells, less than 1/3 of the lateral contributes the bulk of the production from the well. The presence of an aquifer or gas cap can significantly shorten the well life and make it uneconomical. This is especially true for offshore fields where well intervention is difficult and expensive.
The use of ICD's or inflow Control Devices is becoming more prevalent and can result in significantly increasing the economic life of a well. Most of the devices currently in use are passive and once set, cannot be changed or modified. ICD's can be used for both producers and injectors and are very effective when used in conjunction. Prior to completing a well with ICD's, considerable design work needs to be done to determine the optimal settings for the life of the well. In order to properly design the ICD configuration, extensive simulations are required from the newly drilled well properties. A poorly designed well can result in choking production from good reservoir sections or resulting in early breakthrough. This paper discusses the different types of ICD's available and the process to properly design the well completion. The different modeling tools available are presented and the implementation process in the field reviewed. Two field examples are given and the results from these installations presented. A process for the proper design and common issues are also presented. The use of screens coupled with ICD's for sand control is also discussed.
The Role of Calcite in CO2 Increase 25% During Cyclic Steam Injection in Sandstone Heavy Oil Reservoir: Case Study
Authors: Nengkoda Ardian 
Published: May 2012

Abstract
Cyclic steam EOR pilot project has been deployed in sandstone reservoir type, heavy oil field of Petroleum Development Oman, South Operation, and recently within August to October 2011 showing an interesting CO2 increase from 1% to the level of 25% mol in gas phase as phenomena. This paper discuss the implementation of Root Cause Analysis, developing steam core flood techniques to understand the increasing mechanism of CO2, and the proactive well surveillance will help to monitor accurately the increasing level and the impact. The impact of high CO2 to well and operation integrity also have been studied. The Low GOR (&lt;25 scf/bbl) found to be a limitation of reservoir, while the heavy oil characteristics 14 API will limit a level increase from the well. The only possible CO2 increased are coming from a thermal evaporation mechanism of formation water and rock mineralogy. The basis simplified chemistry model have been developed as steam energy reaction, one mole of CO2 was produced for each mole of H2O injected at steam temperatures. From the detail mineralogy study found that the sandstone reservoir from the field containing Dolomite and Calcite. The surface CO2 found to be the total amount of evaporation from rock mineralogy, Calcite from formation water and from origin associate reservoir gas. And finally, the CO2 percentage increase in the surface will be less than 3 scf/bbl.
Qatar Shell GTL Implementation of Process Safety Management
Authors: Johnson Andy D. 
Published: May 2012

Abstract
This paper will contains details of the following aspects of Qatar Shell GTL limited's implementation of process safety management.

The business case for Process Safety Management
The continuing incidence of major industrial accidents has driven the recognition that management of process safety requires a different approach from the management of occupational safety.

Process Safety in Design, ALARP Demonstration and the Design HSE Case
Process Safety Management begins with the design of facilities. The paper describes how Shell uses the Hazards and Effects Management Process to identify process safety hazards, assess their risks and manage them to be As Low As Reasonably Practicable (ALARP) at each stage of the Design of oil and gas facilities, and the formal record of this process in a Design HSE Case.

Process Safety Management in Operations – The Operations HSE Case
The paper will describe how the Operations HSE Case is used to continue the management of process safety in operations. The use of a Hazard Register to record the hazards present during operations and the selection of those hazards with high process safety risks. The use of Bowties to record threats that can lead to loss of containment or control and the barriers (either hardware or task related) used to prevent or recover from such loss. The link between the barriers and the operational activities required to maintain those barriers during the lifetime of a facility.

Instilling the right behaviours in Process Safety Management - Chronic Unease
Challenging the risk management of major accidents requires a retuned leadership mindset, so that leaders ask the right questions, and pick up on the weak signals of potential failure. The paper describes what Shell leaders are doing to improve awareness and focus on process safety.
Healthcare-associated infections among pediatric oncology patients in Pakistan: risk factors and outcome
Authors: Siddiqui Naveed- ur-Rehman , Wali Rabia , Haque Anwar- ul , Fadoo Zehra 
Published: May 2012

Introduction: Pediatric oncology patients are at increased risk of contracting healthcare-associated infections (HAIs), which are responsible for increased morbidity and mortality rates as well as treatment costs. This study aimed to identify the frequency of HAIs among pediatric oncology patients and their outcome. Methodology: Pediatric oncology patients admitted between January 2009 and June 2010 in a pediatric ward at Aga Khan University Hospital, Karachi, Pakistan, who developed HAIs, were analyzed. Results: A total of 90 HAIs were identified in 32 patients in 70 admissions. The HAI rate among pediatric oncology patients was 3.1/100 admission episodes. Bloodstream infections (63 episodes, 90.0%) were the most common, followed by urinary tract infection (two episodes, 2.9%). Gram-positive infections were seen in 54 (60%) patients, followed by Gram-negative infection in 34 (37.8%), and fungi in 2 (2.8%) cases. Coagulase negative staphylococci was the most common Gram-positive and Escherichia coli and Pseudomonas aeruginosa were most common Gram-negative infections. Mortality rate among pediatric oncology patients who developed HAIs was 12.5% (4/32). Total parental nutrition use and length of stay longer than 30 days were the identified risk factors associated with increased mortality among pediatric oncology patients who developed HAIs. Conclusion: We report an HAI rate among pediatric oncology patients of 3.1/100 admission episodes with a mortality rate of 12.5% in Pakistan. Further studies should be done, especially in the developing world, to identify the risk factors associated with increased mortality among pediatric oncology patients so that adequate measures can be taken to reduce the mortality among these patients.
Comparison of four serological assays for the diagnosis of Chlamydia trachomatis in subfertile women
Authors: Muvunyi Claude , Claeys Laurens , De Sutter Tineka , De Sutter Petra , Temmerman Marleen , Van Renterghem Lieve , Claeys Geert , Padalko Elizaveta 
Published: May 2012

Introduction: Chlamydia antibody testing (CAT) in serum has been introduced as a screening method in the infertility workup. We evaluated the test characteristics of two ELISA tests compared to micro-immunofluorescence tests (MIFs). MIFs are considered the gold standard in the C. trachomatis IgG antibodies detection. We also compared the accuracy of all CAT tests in predicting tubal subfertility, using laparoscopy as a reference. Methodology: Four commercial serological methods were used to analyse 101 serum samples for the presence of C. trachomatis IgG antibodies from patients at the Infertility Clinic of Ghent University Hospital. The diagnostic utility for prediction of tubal infertility of serological methods was evaluated based on patients' medical records. Results: A comparison of the serological assays showed little difference in the major performance characteristics: the sensitivities of all MIFs and ELISAs were 100% for all assays (except the ELISA Vircell, with a sensitivity of 90%), and the specificities ranged from 92% for MIF Ani Labsystems to 98% for the MIF Focus and ELISA Vircell. As compared to laparoscopy data, CAT positivity in subfertile women with tubal damage (n=40) did not significantly differ from that of subfertile women without tubal damage (n=61): Positive predictive values (PPV) of CAT ranged from 53% to 60% and negative predictive values (NPV) ranged from 62% to 64%. Conclusion: evaluated ELISAs are comparable to MIFs in the detection of C. trachomatis IgG antibodies and should be preferred for large serological studies, especially in resource poor settings.
Mères, migrantes et malades en Guyane et à Saint-Martin : la maternité au croisement de rapports sociaux inégalitaires
Authors: Carde Estelle 
Published: May 2012

Résumé En Guyane et à Saint-Martin, les grossesses en contexte d’infection par le VIH sont plus fréquentes qu’ailleurs en France. Elles sont le fait, dans une grande majorité des cas, de femmes immigrées. Une enquête de terrain a été menée par observations et entretiens auprès de 19 de ces femmes et de 54 professionnels impliqués dans leur suivi social et médical, afin de comprendre les enjeux sociaux qui sous-tendent leurs maternités. Pauvreté, isolement, dépendance vis-à-vis de leurs partenaires, secret sur leur maladie stigmatisée et absence de titre de séjour placent ces femmes dans des rapports sociaux inégalitaires. Ces rapports s’articulent selon des configurations diverses, non seulement évolutives au cours de ces maternités (de la conception au suivi du nouveau-né) mais aussi marquées par les spécificités spatiales de chacun des deux territoires. Pour le système de soins, le défi reste le même sur les deux terrains : atténuer les conséquences, sur la santé des femmes et de leurs enfants, de ces rapports sociaux inégalitaires.
Quel avenir pour l'élevage dans le bassin cotonnier de l'Ouest du Burkina Faso ? Dynamiques agro-pastorales et recompositions territoriales
Authors: Gonin Alexis , Tallet Bernard 
Published: May 2012

Résumé La présentation des systèmes d’élevage dans l’Ouest du Burkina Faso permet de montrer la juxtaposition sur les mêmes espaces de pratiques différentes ; la remise en cause des mobilités pastorales au cours des deux dernières décennies est lourde d’incertitudes : comment repenser la mobilité des troupeaux dans un contexte de fort accroissement des espaces agricoles et de réduction des espaces pastoraux ? La vocation du bassin cotonnier est-elle uniquement agricole ou agro-pastorale ? Derrière la « mise en territoire » des espaces pastoraux se cachent des stratégies d’acteurs aux intérêts divergents. En l’absence de point d’équilibre, c’est l’issue de ces rapports de force qui décidera de la place de l’élevage dans l’économie régionale. Différents scénarios qui en découlent sont envisagés.
À la recherche des « voix » des fallāhīn dans un dossier d’archives judiciaires égyptiennes
Authors: Clément Anne 
Published: May 2012

À travers l’étude du dossier de Mikhīmar, un jeune fallāh (paysan égyptien) condamné à mort pour meurtre en 1893, cet article montre qu’une approche des archives centrée sur les traces matérielles laissées par le processus de composition et de recomposition du dossier permet de restituer en partie la performance des différents acteurs du processus judiciaire, et contribue par là même à jeter une lumière nouvelle sur le système de justice colonial au tournant du xxe siècle. Plus précisément, l’analyse des traces — citations entre parenthèses et pétitions en annexes — laissées par la négociation, qui se déroule tout au long de la procédure entre la famille de la victime et les autorités judiciaires autour de la nature commanditée du meurtre et des poursuites à engager contre les responsables, révèle à la fois la dimension conflictuelle et éminemment politique du processus de décision des magistrats et une capacité d’expression et de contestation du système tout à fait insoupçonnée de la part des fallāhīn.