bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of Effect of Fracturing Fluid on After-Closure Analysis in Gas Reservoirs
Authors: Soliman M.Y.. Y. , Miranda Carlos , Wang Hong (Max) , Thornton Kim 
Published: March 2011

Summary
Published techniques for analysis of after-closure fracture data usually assume single-phase flow. These procedures generally rely on the techniques developed for the analysis of buildup tests. Applying the buildup techniques implies that the injected fluid and reservoir fluid have approximately the same properties. This assumption is generally incorrect in case of minifrac tests where the injected fluid may be very different from the reservoir fluids. This situation is at an extreme when the minifrac test is conducted on a gas reservoir and the injected fluid may be a relatively high-viscosity gelled fluid.
In this paper, we review the basic theory behind after-closure analysis. Using a numerical simulator, minifrac tests are simulated and analyzed for both oil- and gas-reservoir cases where an aqueous phase is injected as a fracturing fluid. Analyses of the numerically simulated falloff data are presented. Guidelines for the analysis of such data have been developed and presented.
Field data are also presented. In one case, breakdown, step-rate, and fluid-efficiency tests (FETs) were performed on a tight gas formation and the data were analyzed. The results of using these various techniques are presented. The consistency of results validates conclusions achieved using the numerically simulated data.
Guidelines for Filler-Material Selection To Minimize Preferential Weld Corrosion in Pipeline Steels
Authors: Mahajanam Sudhakar P. , Joosten Mike W. 
Published: March 2011

Summary
Preferential weld corrosion (PWC) has long been a problem in the oil and gas industry for pipelines used in process facilities, seawater injection, produced-water service, offshore platforms, and downhole-production systems. This paper reviews recent PWC field failures in light of mitigation guidelines from existing literature. Environmental effects take precedence over chemical composition and microstructure in determining PWC susceptibility. Therefore, the primary approach to minimize PWC is continuous corrosion inhibition. The ideal PWC-prevention method would be the use of autogenous welds or welds made with matching consumables. However, this is not a practical option in the field where most pipelines are typically made from carbon (C) manganese (Mn) steels with broad chemical compositions, thereby making them susceptible to PWC. The feasible alternative is to use filler materials with strict compositional control concerning the following elements: nickel (Ni), silicon (Si), and chromium (Cr). In addition, increased-preheat and high-heat input welding processes should be employed to minimize PWC susceptibility.
Well-Integrity Assessment and Assurance: The Operational Approach for Three CO2-Storage Fields in Italy
Authors: D’Alesio P.. , Poloni R.. , Valente P.. , Magarini P.A.. A. 
Published: March 2011

Summary
In 2004 Eni Exploration and Production (E&P) launched the GreenHouse Gases (GHG) Project to develop technologies and select fields suitable for geological sequestration of carbon dioxide (CO2).
For the well area, the project includes Well-integrity assessment: Verify and (if necessary) reinstate the structural integrity of the existing wells.Well-integrity assurance: Establish the technical requirements to ensure the integrity of new CO2-injection wells.
Well-integrity assessment has been carried out by developing and implementing an operational methodology for three Italian fields: Cortemaggiore, Palino-Ascoli-Candela-Satriano (PACS), and Giaurone-Armatella-Gela. This methodology includes the comparison between the sustained casing pressures (SCPs) measured in the annuli and the relevant maximum allowable pressures (MAPs) to estimate how close each well is to losing its safety conditions. Then, the methodology foresees specific investigations for the critical wells to identify the magnitude and possible causes of the SCPs occurrence. Finally, it includes the preparation of suitable remedial and/or monitoring plans.
Stress-analysis studies supported these activities by calculating the mechanical resistance, under the planned operational conditions, of production casings and tubings of the CO2-injection wells.
As for well-integrity assurance, technical requirements for new CO2-injection wells have been established on the basis of the project for Well Cortemaggiore 157 Dir, constructed to carry out the pilot test for the injection of CO2 in a depleted level of the Cortemaggiore field.
Specific studies have been carried out for the PACS and Giaurone-Armatella-Gela fields. The former is a gas field with high CO2 content—CO2 will be separated and reinjected. The latter is an oil field—CO2 injection will be used as an effective means for enhancing oil recovery.
This paper describes the operational approach followed for these activities and describes the main requirements for the new CO2-injection well.
On SAGD in Oil Sands Reservoirs With No Caprock and Top Water Zone
Authors: Al-Turki Ali A. , Gates Ian D. , Maini Brij B. 
Published: March 2011

Summary
The ever-increasing world demand for energy to satisfy current needs and future economic growth has forced the oil and gas industry to exploit challenging energy resources. Heavy oil and oil sands are challenging because of the complexity of reservoirs together with high-oil viscosities, which are often greater than hundreds of thousands to millions of centipoise. Most steam-based recovery processes, such as cyclic steam stimulation (CSS) and steam-assisted gravity drainage (SAGD), require a competent caprock to prevent excessive steam losses and maintain good thermal efficiency and production rates, as well as preventing steam flow to surface. However, there exist significant amounts of oil sands resources, which have little or no caprock; thus, at this point, these resources are considered inaccessible. This research examines the feasibility of using SAGD in oil sands reservoirs with no caprock with detailed thermal reservoir simulation. The results of this research provide guidelines that explain how to implement the SAGD process in shallow oil sands reservoirs with no caprock. This could unlock a resource that is currently considered inaccessible. The results show that vertical chamber growth can be controlled to some extent by using variable pressure operating strategies and coinjection of a noncondensable gas, such as methane. In oil sands reservoirs without caprocks, pressure control is critical, especially if there is to be minimal fluid invasion from the oil sands formation into the water zone above. However, the pressure must be sufficient to delay or prevent flow of water into the steam chamber. This study is important because in Alberta, Canada alone there are billions of barrels of shallow oil sands resources without sufficient caprock to operate conventional high-pressure steam recovery processes, such as CSS and SAGD. The results of the study provide a technical basis to design feasible low-pressure steam processes for such reservoirs.
Noncondensable Gas Distribution in SAGD Chambers
Authors: Yuan Jian-Yang , Chen Joyce , Pierce Gerry , Wiwchar Brian , Golbeck Hart , Wang Xinkui , Beaulieu Gilles , Cameron Shauna 
Published: March 2011

Summary
This paper summarizes a set of SAGD experiments conducted live under an X-ray scanner. These experiments were specifically designed for mapping noncondensable gas distribution and their movement in an active steam chamber during SAGD.
Many researches over the past 3 decades have shown that noncondensable gases may have critical impacts on SAGD performance. Some may be positive and others may be negative, depending on reservoir and operating conditions. To better use the positives, avoid the negatives, and for better SAGD performance predictions, it is crucial to understand how these gases behave in a steam chamber. It is arguable that noncondensable gases tend to accumulate at the steam front where steam condenses. However, this assertion has only been supported by numerical simulations. Field observation data have been too sparse. Meaningful tracking of gas production is not a normal practice in the field.
The first experiment was conducted in an aluminum vessel packed with 4 darcy sands at 1.0 MPa. The second experiment was conducted in a scalable system consisting of a titanium pressure vessel and a PEEK cell, allowing the SAGD experiment to run at 2.1 MPa. Both experiments used bitumen fully saturated with methane at reservoir conditions and were run live under the X-ray scanner. X-ray images were taken at given time intervals. Temperature profiles were obtained directly from thermocouples. Density profiles were computed from the X-ray images. Methane in the free gas phase were calculated and mapped. After each experiment, samples from the opened cell were also tested for additional observation and confirmation.
These experiments confirmed the assertion that noncondensable gas tends to concentrate along the steam front. It was also demonstrated that the steam temperature zone does not coincide with the oil-depleted zone, indicating that in a SAGD reservoir with nontrivial presence of noncondensable gases, temperature measurements at observation wells alone would not reflect the boundary of the steam chamber. The more representative measure of a steam chamber should be the mapping of the oil-depleted zone. A more comprehensive monitoring of gas production plus 4D seismic would be needed to determine the oil-depleted zone in the field operation.
Well-Production Challenges and Solutions in a Mature, Very-Low-Pressure Coalbed-Methane Reservoir
Authors: Okotie Victoria U. , Moore Robert L. 
Published: March 2011

SummaryCoalbed-methane (CBM) production in the San Juan basin of northwestern New Mexico and southwestern Colorado has spanned more than 30 years. Some parts of the field, such as the high-permeability Fairway, are now in a mature stage of reservoir-pressure depletion. Optimization of well-production operations in the Fairway presents many challenges because of its extremely low reservoir pressure (less than 100 psi in some areas), heavy coal-fines production, difficult artificial-lift challenges, increasing CO2%, and the presence of paraffin, inorganic scale, and corrosion.We use history matching by reservoir simulation to help diagnose the causes of well-production inefficiencies and then plan how to mitigate them. Simulation of Fairway wells typically require the use of an increasing reservoir-permeability trend caused by coal-matrix shrinkage with the desorption of methane and CO2. However, we have observed in some Fairway wells that below a reservoir pressure of approximately 300 psi, there is a flattening or even a decrease in the permeability trend. This shift in the permeability trend is likely caused by coal failure (i.e., a change in mechanical properties of coal) that is evidenced in the wells by an increased amount of coal-fines production.This paper is written in two parts. The first part presents the challenges we face in operating Fairway wells and the solutions we have developed to overcome them. Field observations and operating guidelines will be shared, along with well-intervention histories where we have seen success. The second part discusses our use of reservoir simulation to diagnose the causes of reduced well-production efficiency.
Front Self-Correction for In-Situ Combustion
Authors: Paitakhti Oskouei Seyed Javad , Moore Gordon , Maini Brij B. , Mehta Sudarshan A. 
Published: March 2011

Summary
Since it was discovered in the early 1920s, several improvements have been suggested for in-situ combustion (ISC) technology. Top-down combustion displacement is a process proposed for application with horizontal well technologies. In this configuration, air is injected near the top of the reservoir, close to the overburden, through a horizontal well or a number of vertical wells. Fluids are produced from the reservoir through horizontal wells placed near the bottom of the reservoir. In this configuration, the combustion front moves downward with gravity and displaces fluids to the production well.
Combustion front formation and its stability are major concerns in this arrangement. While the short distance between injector and producer addresses the cold oil blocking problem in the reservoir, it has the potential to create air fingers, which could prevent stable advance of the combustion zone in a horizontal plane. Front self-correction must occur to prevent oxygen from fingering to the production wells.
To prove this idea, experiments at reservoir pressure were carried in a 2D SAGD model with Athabasca bitumen. Air was injected into the SAGD steam chamber from the top, and fluids were produced from the bottom. Front advancing directions were monitored by a series of thermocouples located inside the model. It was found that the combustion zone starts spreading horizontally in the model until it reaches a limiting point, then it starts moving downward as a horizontal front. Despite heterogeneity of the oil saturation and relative permeability in the steam chamber and unswept zones, the combustion front moved almost as a horizontal plane and no sharp fingers were recorded in the experiments. These experiments show that stable top-down combustion is feasible.
Offshore-Platform Startup Challenges: Materials Integrity and Remediation
Authors: Mahajanam Sudhakar P.V. , Joosten Mike W. 
Published: March 2011

Summary
Offshore oil- and gas-production environments provide severe challenges in terms of materials selection and day-to-day operations. Several issues encountered during commissioning of a North Sea platform and the remedial actions are presented.
Corrosion protection of carbon-steel bolting by encapsulation was employed to stop deterioration of an improperly applied anodic coating.
Iron contamination from debris generated during topside construction and chlorides from the marine atmosphere provided the conditions necessary for ferric chloride pitting corrosion of uncoated 316 stainless steel (SS), duplex and super duplex SS, and 6% Mo SS pipework and vessels. Several offshore cleaning/coating methods were evaluated, and a new procedure for cleaning was identified that achieved the desired goal without removal of metal or affecting the corrosion-resistant alloy's passive film integrity.
Insulated SS instrument tubing was susceptible to crevice corrosion and chloride stress corrosion cracking (Cl-SCC) under wet insulation at the temperatures generated by the heat tracing. Solutions were suggested to minimize such forms of corrosion.
Coatings exceeding the manufacturer's recommended thickness had been applied to several high-temperature vessels and to pipework to prevent SCC as well as ferric chloride pitting. The potential for coating disbondment at elevated temperatures because of high dry-film thickness (DFT) was evaluated through a testing program and on-site inspections.
Convection at the Edge of a Steam-Assisted-Gravity-Drainage Steam Chamber
Authors: Sharma Jyotsna , Gates Ian D. 
Published: March 2011

Summary
Steam-assisted gravity drainage (SAGD) has become the preferred process to recover bitumen from Athabasca deposits in Alberta. The method consists of a lower horizontal production well, typically located approximately 2 m above the base of the oil zone, and an upper horizontal injection well located roughly 5 to 10 m above the production well. Steam flows from the injection well into a steam chamber that surrounds the wells and releases its latent heat to the cool oil sands at the edge of the chamber. This research re-examines heat transfer at the edge of the steam chamber. Specifically, a new theory is derived to account for convection of warm condensate into the oil sand at the edge of the chamber. The results show that, if the injection pressure is higher than the initial reservoir pressure, convective heat transfer can be larger than conductive heat transfer into the oil sand at the edge of the chamber. However, enhancement of the heat-transfer rate by convection may not necessarily imply higher oil rates; this can be explained by relative permeability effects at the chamber edge. As the condensate invades the oil sand, the oil saturation drops and, consequently, the oil relative permeability falls. This, in turn, results in the reduction of the oil mobility, despite the lowered oil viscosity because of higher temperature arising from convective heat transfer.
Prediction of Asphaltene Precipitation During Solvent/CO2 Injection Conditions: A Comparative Study on Thermodynamic Micellization Model With a Different Characterization Approach and Solid Model
Authors: Tavakkoli Mohammad , Masihi Mohsen , Ghazanfari Mohammad H. , Kharrat Riyaz 
Published: March 2011

Summary
There are different thermodynamic models that have been applied for modelling of asphaltene precipitation caused by various reasons, such as solvent/CO2 injection and pressure depletion. In this work, two computer codes based on two different asphaltene precipitation thermodynamic models--the first being the thermodynamic micellization model with a different characterization approach and the second being the solid model--have been developed and used for predicting asphaltene precipitation data reported in the literature as well as in the obtained data for Sarvak reservoir crude, which is one of the most potentially problematic Iranian heavy oil reserves under gas injection conditions. For the thermodynamic micellization model, a new approach was obtained by applying the characterization method taken from the thermodynamic solid model for oil component characterization. This new approach introduced a new matching parameter to the model, representing the interaction coefficients between asphaltene components and light hydrocarbon components, which resulted in a significant improvement in the thermodynamic micellization model predictions of asphaltene precipitation data under gas injection conditions. The model parameters obtained from a sensitivity analysis were applied in both thermodynamic models, and the experimental data of asphaltene precipitation were predicted. The asphaltene precipitation predictions from the solid model showed good agreement with the data taken under gas/solvent injection conditions. Especially for the trend of the titration curve after the peak point, reasonable agreements were observed which could rarely be found in the available literature. It has been observed that although the thermodynamic micellization model with a different characterization approach is more complex than the solid model, it is able to predict the trends of asphaltene precipitation curves for gas titration conditions reasonably well. Also, its predictions matched well with more experimental data points in comparison to the solid model predictions.
Welfare Reform in the U.S.: A Policy Overview Analysis
Authors: Martin Megan C. , Caminada Koen 
Published: March 2011

AbstractSeveral previous papers have marked the United States as an outlier: high poverty rates, low public social spending but high private social expenditures; a rather strong belief that people are poor because of laziness or lack of will; and remarkable differences across the States due to state discretion. With that established context in mind, this paper analyzes U.S. welfare in more detail, focusing on the impact of TANF—part of the major welfare reform that took place in the United States in 1996. U.S. welfare reform emphasized an American preference for work, and it was a move further away from the strategies other “wealthy” nations use to address poverty. Initially U.S. welfare reform did serve to increase work participation rates, although the earnings of most individuals who left welfare were still below the poverty line, even many years after their exit. We found huge variation of welfare eligibility rights across states, depending on the state's ability to pay and preferences to meet a certain level of social standard or other (social) objectives such as child care, work support and employment programs.
Energy Burden and the Need for Integrated Low‐Income Housing and Energy Policy
Authors: Hernández Diana , Bird Stephen 
Published: March 2011

AbstractUsing detailed sociological and public health qualitative interview data, we demonstrate that energy poverty is more pervasive, and results in a greater energy burden for low‐income tenants, than many policymakers would assume. This is due in part to a lack of funding, policy non‐coordination, and a lack of understanding of the social and economic benefits of energy conservation, energy education, and flexible utility billing policies. Examining LIHEAP, weatherization, utility, and housing assistance policies, we suggest that a coordinated, regional approach to home energy and housing policy that integrates programs in each area will provide a more coherent policy solution.
The Next Generation of Poverty Reduction Strategy Papers in Africa: What is the Role for Capacity Buiding?
Authors: Ikhide Sylvanus I , Obadan Michael I 
Published: March 2011

AbstractIn the late 1990s and at the early path of this century, most African economies embraced poverty reduction strategy papers (PRSPs) as a policy prescription out of the poverty abyss into which their economies had sunk since the early 1970s. The results from the first generation of PRSP processes have been encouraging and have acted as a stimulus for the second generation PRSPs. However, capacity constraints have tended to create difficulties for many of these countries, slowdown the pace of implementation of the PRSP, as well as undermine the achievement of objectives. This study, focusing on a sample of countries in Africa, attempts to identify and characterise the nature of capacity building constraints in the formulation and implementation of PRSPs and suggests capacity building efforts for dealing with these constraints. Four major areas of capacity constraints were identified: capacity for poverty and social impact analysis, monitoring and evaluation, absorptive capacity, public expenditure management, and constraints on prioritisation. Given funding constraints, the paper concludes by prioritising areas of capacity building interventions by capacity building institutions and donors in a bid to strengthen capacity building in Africa.
Review of The Crisis Caravan: What's Wrong with Humanitarian Aid?
Authors: Beard Virginia Parish 
Published: March 2011

AbstractLinda Polman, drawing from over fifteen years experience reporting from war zones for a range of European radio stations and newspapers, uses rich case study analysis to posit a picture of ineffective and ill‐targeted foreign assistance that departs alarmingly from the industry's claim of impartial assistance to victims of conflict. On the contrary, Ms. Polman paints a convincing portrait of captured aid, supporting the business of war and military strategy, pushing the ethical boundaries on such questions as whether doing something is always better than doing nothing, and whether good intentions are enough to warrant certain means and outcomes. She argues for greater transparency, honesty and accountability across the humanitarian assistance industry with rich, detailed accounts of areas for needed change. This is an essential read for students, practitioners and scholars of international conflict, development and aid.
The Good‐looking National Commission on Fiscal Responsibility and Reform
Authors: Dobelstein Andrew 
Published: March 2011

AbstractAndrew Dobelstein, Professor Emeritus at The University of North Carolina ‐ Chapel Hill School of Social Work responds to Eric R. Kingson's article entitled “A Tale of Three Commissions: The Good, The Bad, and The Ugly.” The article was published as part of Poverty & Public Policy Volume 2, Issue 3.