bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mobilization of Waterflood Residual Oil by Gas Injection for Water-Wet Conditions
Authors: Oren P. E. , Billiotte Joël , Pinczewski W. V. 
Published: December 2007

Summary
Mechanisms by which waterflood residual oil is mobilized and recovered during tertiary gasflooding at quasistatic rates and strongly water-wet conditions were investigated with 2D glass micromodels. Two three-phase oil/water/gas systems were used in the displacement experiments. One system had a positive spreading coefficient, the other a negative coefficient. Results for the two systems were compared to determine the differences in displacement mechanisms and oil recovery efficiency. Displacement in both systems proceeds by a double-drainage mechanism where a gas/oil displacement is always associated with an oil/water displacement. The oil/water displacement leads to coalescence and reconnection of oil blobs. Oil recovery was significantly higher for the positive spreading system. The higher displacement efficiency resulted from flow through thin but continuous oil films that always separated the oil and water phases in the positive spreading system. The absence of oil films and the possibility of direct gas/water displacements reduced oil recovery for the negative spreading system.
Phase Behavior, Fluid Properties, and Displacement Characteristics of Permian Basin Reservoir Fluid/CO2 Systems
Authors: Creek J. L. , Sheffield J. M. 
Published: December 2007

Summary
The formation of a CO2-rich second "liquid" phase in mixtures of CO2 and Permian Basin reservoir fluids now is well-established. This paper presents our experimental measurements of fluid properties in this liquid/liquid/vapor (L1/L2/V) region and their effects on the displacement of Permian Basin crude oil samples with CO2. We first present detailed measurements of phase volumes, viscosities, densities, and interfacial tensions (IFT's) for a Permian Basin/CO2 reservoir fluid system. We describe how these properties change as the L1/L2/V region is traversed. The extent to which the Peng-Robinson equation of state (EOS) is capable of modeling these properties also is discussed. We have observed that the unusual behavior in slim-tube displacement tests at Permian Basin reservoir conditions correlates with the formation and properties of these phases. Conventional criteria defining minimum miscibility pressure (MMP)—e.g., recovery at 1.2 PV injected—are unsatisfactory for these systems. We propose criteria based on maximum ultimate recovery and secondary observations that are more satisfactory.
A Semianalytical Thermal Model for Linear Steamdrive
Authors: Gajdica Ronald J. , Brigham William E. , Aziz Khalid 
Published: December 2007

Summary
A semianalytical model was developed for 1D linear and 2D cross-sectional systems. New methods are introduced to determine the shape of the steam front and the sweep efficiency of the water front. The model was much faster than a thermal simulator but produced accurate matches of thermal simulator results.
Surfactant Flood Process Design for Loudon
Authors: Maerker J. M. , Gale W. W. 
Published: December 2007

SummaryLaboratory steps required to design a successful surfactant flooding process for the high–salinity Loudon field are described. These steps involved (1) phase-behavior tests to identify two synthetic surfactant components; (2) Berea coreflood tests to establish the desirability of incorporating polymer in the microemulsion and to optimize blend ratio, microemulsion salinity, drive–water salinity, and bank size; and (3) Loudon rock corefloods to provide a final check in reservoir core material. The process recovered significant quantities of residual oil in two 1–acre pilot tests without the use of a cosurfactant, a cosolvent alcohol, or a low-salinity preflush.
Use of Mixed Surfactants To Generate Foams for Mobility Control in Chemical Flooding
Authors: Llave Feliciano M. , Olsen David K. 
Published: December 2007

SummaryThe application of mixed surfactant foams as an alternative method for mobility control behind a low-concentration chemical flood was evaluated in laboratory experiments. Results indicated that use of alternating slug cycles of gas and selected mixed surfactants resulted in significantly higher differential pressures, Δp, compared with use of only the individual surfactant components, even at low surfactant concentrations. Foams generated with these systems were more stable, even in the presence of oil. The synergistic effect of enhancing foam-generation behavior and stability of these types of systems can improve propagation of a mobility-control front through porous media.
Effect of Polymers on the Imbibition Process: A Laboratory Study
Authors: Ghedan Shawket G. , Poettmann Fred H. 
Published: December 2007

Summary
Polymer flooding of fractured reservoirs is common. In water-wet fractured reservoirs, the primary recovery mechanism may be imbibition. This paper presents results of an experimental study investigating the effect of polymers on the imbibition process. Two sets of experiments, static and dynamic, were performed. The static experiments showed that the amounts of oil ultimately recovered by water and polymer-solution imbibition are practically equal. The rate of oil recovery by the polymer solutions, however, is always less than the rate with water. The dynamic experiments consisted of flooding oil-saturated fractured cores through the fractures. The oil-recovery behavior in these experiments depended not only on the rate of injected fluid imbibition from the fracture into the matrix blocks, but also on the operating injection rate and the efficiency of the injected fluid in displacing the oil in the fracture.
An Application of Geostatistics and Fractal Geometry for Reservoir Characterization
Authors: Aasum Yngve , Kelkar Mohan G. , Gupta Surendra P. 
Published: December 2007

Summary
This study presents an application of geostatistics and fractal geometry concepts for 2D characterization of rock properties (k and ϕ) in a dolomitic, layered-cake reservoir. The results indicate that lack of closely spaced data yield effectively random distributions of properties. Further, incorporation of geology reduces uncertainties in fractal interpolation of wellbore properties.
Effects of CO2 Solubility in Brine on the Compositional Simulation Of Co2 Floods
Authors: Enick R. M. , Klara S. M. 
Published: December 2007

Summary
A compositional simulator was modified to account for the effects of brine on CO2 solubility and aqueous-phase density and viscosity. Simulations of oil displacements using continuous injection of CO2, CO2 slugs, and CO2 water-alternating-gas (WAG) injection were conducted to determine the effects of brine on the performance of CO2 EOR processes.
Borehole-Stability Analysis for the Design of the First Horizontal Well Drilled in the U.K. Southern V Fields
Authors: Fuh G. F. , Dew E. G. , Ramsey C. A. , Collins Keith 
Published: December 2007

Summary
This paper presents the method and results of a borehole-stability analysis conducted on the first horizontal well successfully drilled in the North Valiant field in the Southern North Sea. Previous drilling data obtained from the same area were analyzed by numerical simulations of potential mechanical behavior of the wellbore. The magnitude of the in-situ horizontal stresses was determined by the analysis of fracture-stimulation data from wells in the fields. The directions of the stresses were derived from anelastic-strain-relaxation (ASR) measurements of fresh cores. Effects of hole azimuth on wellbore stability were evaluated. The analysis resulted in a design of optimum mud weights for maintaining borehole stability during drilling. This paper also discusses field results and well completions.
Dynamic and Static Filtrate-Loss Techniques for Monitoring Filter-Cake Quality Improves Drilling-Fluid Performance
Authors: Chesser B. G. , Clark D. E. , Wise W. V. 
Published: December 2007

Summary
This paper describes properties that are desirable in a water-based filter cake and test methods that can be used to measure these properties. One method uses a dynamic filtrate-loss apparatus that stirs the fluid mechanically during filtration. Test results show that the initial dynamic filter-cake formation is very important in controlling all future filtration properties and cake quality. The various factors affecting filter-cake quality and how they can be controlled to give better field performance are discussed.
Real-Time Pore-Pressure Evaluation From MWD/LWD Measurements and Drilling-Derived Formation Strength
Authors: Rasmus J. C. , Stephens D. M. R. Gray 
Published: December 2007

Summary
Traditional pore-pressure interpretations in tertiary undercompacted shales have been based on empirical relationships between a particular measurement (such as resistivity) and pore pressure in pounds per gallon. It is well-known, however, that the measurements are responding to the "excess" porosity in the shale rather than to the pore pressure directly. A new technique is illustrated in which all available measurements are first characterized in terms of this excess porosity and lithology with measurement-response equations. This allows a mathematical minimization technique to solve simultaneously the various measurement-response equations for this porosity and lithology on a foot-by-foot basis. A conventional compaction porosity/effective-stress model is then used to determine the additional pore pressure caused by this excess porosity. The result is a single pore-pressure estimate that is independent of the number of measurements and that has an accuracy that improves with the total number of measurements used in the interpretation. The interpretation can be performed at the wellsite in real time by use of rate of penetration (ROP), measurement while drilling (MWD), and logging while drilling (LWD) measurements or after drilling by use of these measurements in conjunction with wireline measurements.
Cement Sheath Stress Failure
Authors: Goodwin K. J. , Crook R. J. 
Published: December 2007

Summary
Observation of the sudden appearance of annular pressure in wells exposed to high temperature changes or excessive internal casing pressure prompted a laboratory investigation to simulate conditions under which cement sheath failure could occur and thereby define the causes, characteristics, and limits of the problem. Cement sheath failure is manifested by interzonal problem. Cement sheath failure is manifested by interzonal annular-fluid movement and abnormally high annular pressure at some point behind the casing up to and at the surface. Cement sheath point behind the casing up to and at the surface. Cement sheath failure can be observed in any producing area where excessive flowing temperatures exist at the surface or where excessive internal casing test pressures are used. The detrimental effects of cement sheath failure are numerous and may include lost revenue from lost production, potentially hazardous rig operations (especially when annular isolation loss creates shallow-water sands supercharged with gas), and potentially hazardous producing operations. Exposure of steel casing to excessive temperature increases or internal test pressures causes diametrical and circumferential casing expansion. This circumferential force creates a shearing force at the cement/casing interface, causing failure at the cement/casing interface or radial fracturing of the cement sheath from the inner casing surface to the outer casing (or borehole) surface.
Closed-Loop Operation With Alternative Dewatering Technology
Authors: Halliday W. S. , Bray R. P. , Youens J. W. 
Published: December 2007

Summary
The introduction of dewatering devices for closed-loop drilling-fluid circulating systems and reserve pits is derived from technology that has been used in the industrial- and sanitary-waste treatment industries for years. This paper describes an overview of the need for closed-loop systems and provides the optimum design layout, including the fit of a dewatering device, for a drilling location. The introduction of a nonconventional dewatering device, called a screw press/thickener, is reviewed. A case history describing use of this technology in a southern Louisiana inland-marsh-area well is analyzed for the technical and economic viability of operating in a closed-loop mode. Results from this effort include a viable alternative to hauling off waste fluids from drilling sites and the realization that use of this technology can be justified economically.
An Experimental Study of Miscible Displacements in Heterogeneous Carbonate Cores Using X-Ray CT
Authors: Hicks Paul J. , Narayanan K. Ram , Deans Harry A. 
Published: December 2007

SummaryA series of flow visualization experiments have been conducted with X-ray computerized tomography (CT) on 10.16-cm-diameter carbonate core samples to study local displacement mechanisms on a 1-mm scale. Liquid-phase miscible displacement experiments were performed with and without a residual phase. Simulations have been performed with a linear, 3D cell model that includes capacitance effects.
Microscopic Imaging of Porous Media With X-Ray Computer Tomography
Authors: Jasti Jay K. , Jesion Gerald , Feldkamp Lee 
Published: December 2007

Summary
This paper presents a new method for imaging the 3D microstructure of porous media. The method is based on high-resolution X-ray computer tomography (CT) where a cone-shaped, diverging X-ray beam is used to generate 2D transmission images. Unlike traditional X-ray CT, a 3D reconstruction array is created directly instead of creating a series of 2D slices. This allows direct measurement of 3D geometric and topologic properties of porous media on a microscale. Our results also demonstrate the effectiveness of the high-resolution system for imaging the distribution of two fluid phases in the void space. The imaging system overcomes the limitations of current methods and has enormous potential for quantifying the microstructure of chaotic porous media.
Impact of Miscible Flooding on Wettability, Relative Permeability, and Oil Recovery
Authors: Rao Dandina N. , Girard Marcel , Sayegh Selim G. 
Published: December 2007

Summary
The fluid-flow effects in miscible gas processes were studied in several series of corefloods involving water-wet, intermediate-wet, and oil-wet reservoir systems. Three more series of floods were conducted in Berea cores for the same three crude oils used in the previous set. Each of the coreflood series involved three cycles of water and miscible gasfloods, with each cycle consisting of the steps necessary to cover the range of saturations from connate water to miscible flood residual oil saturation (ROS). The results from these flow tests revealed that the oil/water relative permeabilities, saturations, and oil recoveries can be significantly different from cycle to cycle, indicating alterations in the in-situ wettability caused by miscible flooding. These wettability alterations had a significant positive effect on the miscible flood oil recoveries in the case of intermediate-wet and oil-wet reservoirs, while their influence in a strongly water-wet reservoir was negligible. In some cases, a mixed-wettability condition developed as a result of miscible flooding, resulting in higher subsequent waterflood oil recoveries. The water/oil relative permeability ratios have been used to identify the development of mixed-wettability in cores.
Theory and Implementation of a Borehole Caliper Measurement Made While Drilling
Authors: Paske W. C. , Rao M. V. , Twist J. R. , Mack S. G. , Spross R. L. 
Published: December 2007

Summary
Like comparable wireline measurements, measurement-while-drilling (MWD) formation-evaluation tools are dependent on the borehole condition. Because of this dependency, the borehole size must be known for appropriate borehole corrections to be made to porosity measurements. This paper describes caliper measurements that can compute the effective diameter of a uniform or nonuniform borehole with nonmechanical means. The basis for the caliper measurement is a gamma/gamma density sensor that uses asymmetric detector placement to define the borehole size. The derivation of the caliper is presented with field log comparisons.
The Effect of Wellbore Condition on Wireline and MWD Neutron Density Logs
Authors: Allen David F. , Best David L. , Evans Mike , Holenka Jacques M. 
Published: December 2007

Summary
The wellbore condition and its corresponding effect on log readings must be assessed and corrected for during log quality control and formation evaluation. Differences arise between measurement-while-drilling (MWD) and wireline neutron density, photoelectric factor (PEF) logs made in the same well because the two systems respond differently to the wellbore environment. Differences also occur because of changes in wellbore condition over time.
Determination of the Effective Stress Law for Permeability and Deformation in Low-Permeability Rocks
Authors: Warplnski N. R. , Teufel L. W. 
Published: December 2007

Summary
Laboratory experiments were performed to determine the effective stress law of tight sandstones and chalk for permeability and deformation. Permeability and volumetric strain data were taken at various stresses and pore pressures and were analyzed with a statistical model-building approach. Results show that the effective stress laws for both processes are variable with stress and pressure, depend on the material, and do not agree well with present theories.
Diagnosis and Evaluation of Fracturing Treatments
Authors: Ayoub J. A. , Brown J. E. , Barree R. D. , Elphick J. J. 
Published: December 2007

SummaryThis paper introduces the pressure derivative in fracturing-pressure analysis. The derivative is shown to enhance the analysis capabilities significantly. The interpretation methodology is presented, and several field data sets and simulations are discussed to illustrate the technique.
Field Performance in the Practical Application of Chlorine Dioxide as a Stimulation Enhancement Fluid
Authors: McCafferty J. F. , Tate E. W. , Williams D. A. 
Published: December 2007

Summary
New, innovative, and successful application technology has evolved in the practical use of chlorine dioxide for well stimulations. The safe generation and use of chlorine dioxide is paramount in well-stimulation procedures. More than 1, 000 well stimulations have been completed safely with the described method of chlorine dioxide generation. Guidelines and operational procedures have been established for the safe handling of chlorine dioxide in well stimulations. Chlorine dioxide is a powerful oxidant that has been coupled safely with conventional acidization to stimulate producing wells, waterflood injection wells, and saltwater disposal wells. Field applications of chlorine dioxide and acid indicate a synergistic relationship that increases the longevity of the stimulation by removal of formation skin damaging agents. Field results correlate well with laboratory core tests for remediation of formation skin damage. This technology is being applied successfully with consistent results in the V.S., although safety has been a primary issue. This paper provides safe guidelines for the process.
Critical and Subcritical Flow of Multiphase Mixtures Through Chokes
Authors: Perkins T. K. 
Published: December 2007

SummaryEquations that describe isentropic (adiabatic with no friction loss) flow of multiphase mixtures through chokes can be deduced from the general energy equation. These flow equations are valid for both critical and subcritical flow. Equations, physical property correlations for oil/water/natural gas systems, and a computer method that will handle both flow regimes are described. The procedure will determine whether flow will be in the critical or subcritical regime. The analysis method has been tested by comparing measured and calculated flow rates of 1, 432 sets of literature data comprising both critical and subcritical air/water, air/kerosene, natural gas, natural gas/oil, natural gas/water, and water flows. An average discharge coefficient of 0.826 gave a negligible average error with a 15.4% standard deviation.
A Method for Correcting Dimensionless Fracture Conductivity for Non-Darcy Flow Effects
Authors: Gldley J. L. 
Published: December 2007

Summary
This paper provides a method of extending the concept of dimensionless fracture conductivity to the design of fracture conductivity in wells to be produced at rates that cause non-Darcy flow down the fracture. Such flow rates are common in gas wells and occasionally occur in oil wells. The correction requires knowledge of the expected producing rate and calculation of a Reynolds number characterizing flow in the fracture near the wellbore.
Material-Balance Techniques for Coal-Seam and Devonian Shale Gas Reservoirs With Limited Water Influx
Authors: King G. R. 
Published: December 2007

Summary
This paper presents the development of two material-balance methods for unconventional gas reservoirs. One method is appropriate for estimating original gas in place; the second is appropriate for making reservoir predictions. These techniques differ from the material-balance methods for conventional gas reservoirs in that the effects of adsorbed gas are included. For estimating original gas in place, the assumption of equilibrium between the free- and adsorbed-gas phases is required. No additional assumptions are required for reservoir predictions.
Considerations Affecting the Scaling of Displacements in Heterogeneous Permeability Distributions
Authors: Hewett Thomas A. , Behrens Ronald A. 
Published: December 2007

Summary
Dispersion and convection scaling can be used to model 1D miscible and immiscible flows, respectively, but these scaling techniques fail in multidimensional heterogeneous permeability distributions. The length dependence observed for dispersion induced by correlated heterogeneity in miscible displacement processes precludes the definition of an effective dispersion coefficient. Effective relative permeabilities can be defined that will reproduce the results of the cross-sectional simulations from which they were derived, but complications arise when they are used in areal models.
Modeling the Vertical Confinement of Injection-Well Thermal Fractures
Authors: Clifford P. J. , Berry P. J. , Gu Hongren 
Published: December 2007

Summary
Cooling of rock by water injection frequently causes fracturing of wells. This paper describes a 3D simulation model of thermally induced fracturing. It is used to show that fractures often tend to grow vertically into permeable zones. Procedures are outlined for confining fracture growth in wells where it will assist waterflood sweep performance.
Use and Application of Permanent Downhole Pressure Gauges in the Balmoral Field and Satellite Structures
Authors: Shepherd C. E. , Neve Patrick , Wilson D. C. 
Published: December 2007

Summary
Downhole gauges installed in Block 16/21 in the North Sea have given invaluable real-time data during extended well testing. These data have improved our understanding of Balmoral and Glamis well and reservoir behavior in the early stages of production. The long-term reliability of these systems has been disappointing. We hope that experience gained with these systems will help others considering their use or contemplating further development of downhole pressure systems.