bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of Fracture-Matrix Fluid Flow Interactions Using X-Ray CT
Authors: Alajmi A. F. , Grader A. S. 
Published: December 2007

Abstract
Multi-phase fluid flow in fractured rocks is essential for maintaining and enhancing oil and gas recovery. The fluid flow interaction between the fractures and the matrix has a significant impact on displacement processes. This paper presents two-phase flow displacements in layered Berea samples that have been artificially fractured. Two experiments were conducted in this work. In one experiment, the fracture was induced at the inlet end of the core allowing us to study diverging flow, and in the second experiment, the fracture was induced at the outlet end permitting us to study converging flow. The temporal and spatial saturation distributions of the two cases were determined using x-ray computerized tomography (CT).
The presence of the fracture delayed the recovery processes and significantly reduced the breakthrough time. Three different fluid flow behaviors were observed at three regions in the sample, the fracture region, at the tip of the fracture, and at the non-fractured region. At the tip of the fracture, the two experiments showed different fluid flow patterns. The displacement process in the fractured region was a two-dimensional process with a strong vertical flow component in the high permeability/porosity layers. The displacement contrast between the layers was more pronounced in the fractured region than in the non-fractured region. The low permeability/porosity layers had high saturation of the displaced fluid even at late time. Oil recovery from waterflooding was delayed due to fluid bypassing caused by the fracture.
A Modified Equation of State for Gas-Condensate Systems
Authors: Erdogmus M. , Adewumi M. A. 
Published: December 2007

Abstract
Accurate prediction of thermophysical properties is an essential requirement for optimum design and operation of most process equipment involved in petroleum production, transportation, and processing. Equipment failure is often directly attributed to lack of accurate design data. Methods of fluid property prediction can be divided into three main categories, namely the Corresponding States Theory (CST), Equation of State (EOS) model, and Activity Coefficient Model (ACM). The EOS approach is most popularly used for natural gas systems due to its applicability at high pressures for both liquid and vapor phases.
Probably the most successful cubic equation of state for natural gas property calculation is the one proposed by Peng and Robinson (PR)1. However, Peng-Robinson EOS assumes a fixed value of critical compressibility factor and, as a result, the predicted densities of the saturated liquids and the predicted critical volumes differ considerably from experimental values. Patel and Teja (PT)2 introduced a substance dependent critical compressibility factor that allowed them to more accurately reproduce the experimental saturated liquid volume at a particular temperature.
The present work is an extension of that of Patel and Teja. The modified Patel and Teja’s EOS improves the prediction of liquid phase density and vapor liquid equilibrium. A comprehensive assessment of the modified equation-of-state is conducted through performance comparison with the more popular equations of state. For saturated liquid volume predictions, the improved equation of state yields 33% and 11% improvement over PR and PT EOS, respectively. For vaporization equilibrium ratio predictions, 36% improvement over PR and 67% improvement over PT EOS are observed.
Modeling Flow in Geometrically Complex Reservoirs Using Hexahedral Multi-Block Grids
Authors: Jenny Patrick , Wolfsteiner Christian , Lee Seong H. , Durlofsky Louis J. 
Published: December 2007

Abstract
A hexahedral multi-block grid formulation for the modeling of two phase reservoir flows is developed and applied. Multi-block approaches are well suited to the modeling of geometrically complex features while avoiding many of the complications of fully unstructured techniques. Important implementation issues, including the accurate treatment of grid non-orthogonality and full tensor permeability (through use of a 27-point finite difference stencil), the treatment of exceptional cases arising when five blocks intersect, and a new well model which allows for the accurate resolution of near-well effects, are discussed. Solution efficiency issues, including the use of tensor splitting and the linear solution technique, are also discussed. The actual grid generation step is accomplished using a commercial package. Results for a variety of cases, involving flow through geologically complex systems and reservoirs with horizontal and deviated wells, are presented. Comparison with analytical results demonstrates the high level of accuracy of the 27-point formulation and the new well model. The method is also applied to a realistic example involving flow through a heterogeneous faulted system. This example illustrates the types of geometrically complex systems that can be modeled using the hexahedral multi-block approach.
Upscaling of Two-Phase Relative Permeability in Heterogeneous Porous Media
Authors: Rodriguez A. A. , Araujo M. 
Published: December 2007

Abstract
In this work we present some recent developments related to the simulation of two-phase flow in porous media. It is shown here, a new formulation to solve the two-phase flow problem based on the use of renormalization techniques on hierarchical lattices. This method allows us to perform simulations about 1000 times faster than those obtained using conventional methods. In this work we have used an eight-shape lattice on which we have discretized the flow equations including the effect of capillary pressure. Our findings show that for the homogeneous case, the results are almost exact compared to the results obtained using the usual methods. In other results, we prove that the oil residual saturation and relative permeability curves have a strong dependence on the size and disorder of the system.
Gaseous Emission Monitoring in the Land Area of the Western Niger Delta
Authors: Ozumba C. I. 
Published: December 2007

Abstract
The Shell Petroleum Development Company as part of her environmental management programme monitors gaseous emissions in its flare sites located all over the Niger Delta basin. This paper details the findings of this programme in a full year of monitoring in the Land Asset Area of the Western Niger Delta. The parameters measured include, heat radiation, soil temperature, noise levels, smoke density, air turbulence, wind speed/direction, air quality (Sox, Nox, Total Suspended Particulate matter, and other volatile organic compounds) and physico-chemical parameters of rain water. These parameters are monitored at various distances from the flare site point source. Results show that all these parameters are currently well below the limits accepted by the World Health Organisation, the Department of Petroleum Resources in Nigeria and the Federal Environmental Protection Agency – FEPA (now Federal ministry Of Environment – FMENV).
An Evaluation of the Department of Energy Naval Petroleum Reserve No. 3 Produced Water Bio-Treatment Facility
Authors: Myers James E. , Jackson Lorri M. , Bernier Rene F. , Miles David A. 
Published: December 2007

Abstract
The Department of Energy (DOE) Naval Petroleum Reserve No. 3 (NPR-3) produced water bio-treatment facility effectively treats an average of 35,000 barrels of water per day. All discharge limits are met. The functional component parts of the bio-treatment facility consist of cooling, blending, oil/water separation and biological treatment. The bio-treatment facility replaced subsurface injection saving $175,000 per year on utilities ($3.5MM over the 20-year life expectancy). The surface discharge of the treated produced water benefits wildlife by keeping a normally dry streambed wet year-round with an abundance of wetland plants for forage.
This bio-treatment facility evaluation is based on site observations over the past four years, review of historical discharge data and a one-time sampling event at eight locations within the facility in September of 1999. The suite of analytical tests include BOD5, COD, TOC, TIC, TPH, O&G, GRO, DRO, BTEX, Ca, Mg, SO4, TKN, NH3, NO3, Alkalinity, pH, EC, hardness, H2S, P (total), PO4 (ortho), TDS, TSS, turbidity and VS. In addition, selected temperature and flow measurements were collected. Hach Biological Activity Reaction Tests (BARTs) were used to measure microbial activity in the water and soil columns and to demonstrate the "substrate effect." The sampling event occurred shortly after an upset event that resulted in a hydraulic surge, elevated temperatures and skimming difficulties. In spite of the upset, the bio-treatment facility's removal rates were &gt;90% for nearly all analytes. The extent of hydrocarbon removal ranged from 95% to 100%.
The areas identified for potential improvement to the bio-treatment facility include cooling capacity, solids handling/removal, skimming operations, flow control and water control structures, replanting of the wetland (free-water surface and/or subsurface), future discharge limits and water reuse.
Treatment Of Drill Cuttings
Authors: El-sayed Abdullah , El-Naga Kamal H. Abu 
Published: December 2007

Abstract
The environmental impact of oil and gas well drilling is a major issue facing today's petroleum industry.
One of the most difficult environmental problems to resolve at the well site is the disposal of waste mud and cuttings they are often physically unstable and unsuitable for landfill.
They carry with them potential environmental liability when improperly managed or disposed.
Waste solids can’t be left at site untreated, and transporting them for disposal can be expensive and complicated.
Contaminated Water Production in Old Oil Fields With Downhole Water separation: Effects of Capillary Pressures and Relative Permeability Hysteresis
Authors: Inikori Solomon O. , Wojtanowicz Andrew K. 
Published: December 2007

Abstract
Industry operators using downhole water separation technology in bottom water drive reservoirs with water coning problem have employed two major approaches. One approach uses downhole hydrocyclone and pumps to separate water from oil in one co-mingled production stream. This approach involves elaborate completion design and high cost equipment. The second approach, termed "gravity segregation" uses dual completion technology with zonal isolation packer to separately produce the water and the oil and so counter the cone development at the wellbore. Both methods, currently, do not completely eliminate the problem of contaminated water production but reduces it to, perhaps, some manageable level. The growing emphasis on environmental-friendly oil production operation and increasing cost of water handling requires the production of oil-free disposable water in a simple completion design.
This paper presents case studies of the pre-installation design of gravity segregation method for three fields (West Africa, Gulf Canada and Louisiana) with strong water coning problems. The study confirms that old oil fields that have suffered severe water coning exhibit a transitional saturation profile and dispersed oil-water contact. In addition, the imbibition/drainage process of water cone development and reversal induced by gravity segregation creates relative permeability hysteresis effect. The effects should be included in the pre-installation modeling.
The results using numerical simulator, indicate that the combined effects of capillary transition pressures and relative permeability hysteresis are responsible for the production of contaminated water experienced with application of the gravity segregation approach in old oil fields. It also shows how to add an envelope to the well's inflow performance window to accommodate the transition zone. Inside the envelope production of oil-free water from the bottom completion is possible with production of minimal water cut oil at the top. This uncontaminated water could be disposed while operators maximize the use of their pipeline and water separation facilities as well as improve oil recovery.
Produced Water Management Strategy with the Aid of Decision Analysis
Authors: Evans Robin 
Published: December 2007

Abstract
Decision analysis is presented as a tool for carrying out a thorough and logical evaluation of alternative strategies to systematically determine the best available produced water management strategy, both economically and environmentally by the application of environmental accounting.
The use of decision analysis is presented as the framework for conducting integrated produced water management studies. The integration of reservoir engineering, environmental regulations, environmental impact assessment, geochemistry, geological studies, process design, risk analysis, QC and financial appraisals with the aim of optimising scale control will be addressed.
The value of decision analysis is not only in helping to structure information and thinking, but also in providing a vehicle for communication between different groups and technical disciplines. A complex decision problem is decomposed into separate components, often in the form of a decision tree, on which perceptions of options, uncertainties and values can be explicitly represented.
The evaluation of options for produced water management will be used as a case study illustrating the stages of the decision analysis process, which are: Structuring and decomposition of the problem including the evaluation of the options for produced water disposal such as re-injection or surface disposal dependent on environmental regulationsAssessing the payoff of the possible outcomesAssessing risks and uncertainties such as injectivity impairment, aquifer pollution, process upsets, regulation changes etcSpreadsheet construction of decision treesSensitivity analysis and assessing the value of additional information to help finalize the decisionStrategy selection
Tenth SPE Comparative Solution Project: A Comparison of Upscaling Techniques
Authors: Christie M A , Blunt M J 
Published: December 2007

Abstract
This paper presents the results of the Tenth SPE Comparative Solution Project on Upscaling. Two problems were chosen. The first problem was a small 2D gas injection problem, chosen so that the fine grid could be computed easily, and both upscaling and pseudoisation methods could be used. The second problem was a waterflood of a large geostatistical model chosen so that it was hard (though not impossible) to compute the true fine grid solution. Nine participants provided results for one or both problems.
Environmental Data Management Systems for E&P Operations
Authors: Liles Robert J. 
Published: December 2007

Abstract
As environmental managers are faced with an ever-growing number of facilities and environmental regulations, many have opted to implement an environmental data management system. These systems are generally computer-based applications that track, calculate, and report emissions, track permit and regulatory requirements, determine applicability of regulations, track compliance activities, and warehouse pertinent documents. Development of a successful system requires significant planning and also requires that a company's business practices be integrated into the final product. This paper discusses the attributes of a successful system and provides a roadmap for their development and implementation.
Development of Consistent Methodology for Estimating Greenhouse Gas Emissions from Oil and Gas Industry Facilities and Operations
Authors: Lev-On Miriam , Ritter Karin , Retzsch Walter 
Published: December 2007

Abstract
Understanding the sources and quantities of greenhouse gas (GHG) emissions are critical to developing an emissions inventory that accurately represents various oil and natural gas industry segment operations. To address this, API formed a Greenhouse Gas Emissions Methodology Working Group. The working group's objectives are to review, summarize, and recommend methodologies for consistent estimation of greenhouse gas emissions from oil & gas industry facilities.
This paper will discuss the process undertaken to review and compare methodologies used by member companies, national governmental bodies, and intergovernmental experts. It will highlight technical, scope, and boundary considerations that play key roles in the final inventory calculations. It will also present a general classification scheme for all oil & gas industry devices and operations, while identifying the parameters needed to generate robust estimates of emissions for each equipment category and oil & gas industry segment.
Technical & Economic Application Guidelines for Downhole Oil-Water Separation Technology
Authors: Blanco A. E. , Davies D. R. 
Published: December 2007

Abstract
Downhole Oil-Water Separation (DOWS) is a water management technology consisting of a hydrocyclone to separate oil from water together with some form of artificial lift to produce an oil enriched stream to surface and to inject the bulk of the produced water into a disposal zone. Field trials have proven DOWS's operational success at reducing the well's water production, but economic success has been sparser. Increased confidence in DOWS technology depends on the development of improved models and methodologies which: Realistically simulate the complete downhole separation process andEvaluate the operational and economical aspects of DOWS
This paper summarises: The development of a hydrocyclone performance model,Its integration with a reservoir simulator andThe testing of this integrated model against a real field case leading to a reservoir development strategy for evaluating the optimum time for DOWS installation and DOWS economics.
Our single or dual stage, hydrocyclone performance model allows the oil / water separation efficiency to be calculated for a range of operational conditions. A decision tree identifies the optimum DOWS installation time based on both the economical and the operational aspects of the technology. The impact of operational parameters on DOWS viability are assessed, ranked and compared. These include the importance of casing size, electrical power costs, properties of the water disposal zone, potential use of the reject water and the surface water treating costs. As expected, DOWS mechanical reliability is one of the key parameters controlling economic viability.
Use of our DOWS technical and economic models described here, together with the reported application strategy, will allow confident installation of DOWS technology in the field. DOWS may then be counted as a reliable option in the water management armoury and a tool for improved oil recovery.
Diagnosis of Sustained Casing Pressure from Bleed-Off/Buildup Testing Patterns
Authors: Xu R. , Wojtanowicz A. K. 
Published: December 2007

Abstract
When the casing pressure can not be permanently bled off through needle valves at wellhead, the casing is said to exhibit Sustained Casing Pressure (SCP). Since high values of SCP may threaten worker safety and environmental protection, MMS regulations require remedial treatment. Testing of SCP could provide information on parameters causing gas migration and SCP.
A mathematical model for testing SCP buildup has been developed. The objective of the model to identify the flow mechanism of external leak leading to SCP. The model also determines critical parameters of the leak to be used in selecting some remedial actions. Also presented in the paper are two examples of using this model to analyze actual SCP field tests. The analysis gives acceptable estimates of the depth of gas invasion zone, formation pressure, cement conductivity, and expected maximum value of casing pressure.
Improving the Success of Morrow Stimulations the Old-Fashioned Way
Authors: Logan W. D. , Gordon J. E. , Mathis R. , Castillo J. , McNally A. C. 
Published: December 2007

Abstract
The Morrow gas sand reservoirs in southeast New Mexico have permeability values that can range across three orders of magnitude. The best wells are completed naturally; the poorer quality rock usually needs to be fracture stimulated to produce commercially. Early attempts to fracture stimulate the Morrow with water-base systems were only marginally successful. Previous studies have suggested that the poor fracturing response to water-base systems was due to a combination of water-sensitive clays and capillary pressure effects. Early theories were that the Morrow experienced reduced permeability as a result of clay swelling and high water saturations in the zones invaded by fracture fluid filtrate. These issues were addressed by using energized fracture treatments that included high quantities of CO2 and methanol in the fracture fluid. Stimulation success with foams has not been consistent. Successful fracturing response to smaller hydraulic fracture jobs using foams has been observed in higher permeability wells where near-wellbore damage has been successfully bypassed. However, in lower permeability wells where fracture length is critical to stimulation success, foams have not provided economic stimulation results.
Although foams were used to address water-sensitivity issues, undesirable side effects countered the foam benefits. Low viscosities, high friction pressures and high chemical cost resulted in increased screenout frequency and increased treatment cost. Early screenouts with low proppant concentrations have left many Morrow reservoirs producing at rates well below their potential. To achieve optimum inflow potential, a fluid system is required that is capable of developing adequate hydraulic width and transporting larger volumes and concentrations of proppant.
Water-base fracturing fluid technology has come a long way since the early days of Morrow fracture stimulation. Advances in both fluid selection and fracture design now make it possible to use a water-base system to achieve successful stimulation results in the Morrow in southeast New Mexico. The net result of this engineering approach is improved stimulation results with lower treatment cost.
Two examples of successful applications of modern fracturing techniques demonstrate that operators in the Morrow of southeast New Mexico have a choice of fracturing fluids other than CO2 foams.
Morrow Production Enhanced by New, Foamed, Oil-Based Gel Fracturing Fluid Technology
Authors: Vezza Matt , Martin Mike , Thompson Joseph E. , DeVine Carolyn 
Published: December 2007

Abstract
Oil-based fluids were first used in the late 1940's to fracture stimulate a variety of wells, the first of which was in Hugoton Field. Subsequently, fluids evolved with soap and aluminum phosphate esters being employed as gellants. Because gelling, gel stability, and ease of mixing have been historically problematic, a new phosphate ester system has been developed for use in formations which may be damaged by water contact.
The Morrow Formation in the Mid-Continent region is known for its sensitivity to fresh water. Due to this fact, treatment designs have been implemented to reduce the amount of water placed into the formation. Foams and gelled oil treatments have been the options available. Foams, while reducing the amount of water placed in the formation, still have a water phase to deal with. Gelled oils eliminate the water phase, but do not have the benefit of the load recovery assistance provided by the gaseous phase of the foam. This paper details the treatment of the Morrow Formation in Southern Oklahoma in which carbon dioxide is introduced into the gelled oil phase. This practice, while common in Canada, has not been utilized in the United States to a great extent. This paper deals with the development and laboratory testing of the fluid system, the treatment design, and the results of such treatments in Grady County in Oklahoma.