bluuebunny/crossref_metadata_2025_split huggingface dataset:
Guidelines for Ultrasonic Cement-Sheath Evaluation
Authors: Goodwin K. J. 
Published: December 2007

Summary
The primary objective of cement-sheath evaluation devices is to define the presence of set cement in the annulus, regardless of its density, compressive strength, or quality. Accepting the premise that any set cement in the annulus with a compressive strength greater than 0 psi cannot be replaced by squeeze cementing emphasizes the necessity of recognizing ultralow-compressive-strength cement (&lt; 100 psi) from cement-sheath evaluation devices. Typically, most bond logging instruments cannot define satisfactorily the presence of these generally low-density, low-compressive-strength cements (such as foamed cement, cements filled with sponge-like microspheres, cements containing hydrogen for control of annular influx, or any cement contaminated with gas percolation). The ultrasonic cement evaluation instruments can define these gas contaminated, unset, or low-quality cements, provided the computing parameters are set and the tools calibrated correctly. This paper provides the mechanisms and data required to calibrate the ultrasonic cement evaluation devices correctly and the correct computing parameters for cement-sheath evaluation. Correct interpretation of the cement quality and quantity in the annulus permits the formulation of intelligent annular squeeze decisions.
Oil-Based Drilling Mud as a Gas-Hydrates Inhibitor
Authors: Grigg R. B. , Lynes G. L. 
Published: December 2007

Summary
Gas-hydrates formation must be considered when petroleum reservoirs are developed in arctic regions and deepwater environments. This paper demonstrates that gas hydrates can form in oil-based muds, but that two major components—oil and dissolved solids in the aqueous phase—significantly inhibit this formation. This work identifies two major components in oil-based drilling mud that affect gas-hydrates formation. The temperature and extent of gas-hydrates formation both can be inhibited significantly, but not necessarily prevented, in oil-based drilling muds. A system that contained 20-vol% water and had an oil-continuous phase inhibited gas-hydrates formation 5 to 10°F. Dissolved solids in a 19.22-wt% calcium chloride (CaCl2) brine inhibited gas-hydrates formation 20 to 25°F and significantly reduced the extent of formation. Gas-hydrates formation in an oil-based drilling mud, prepared with 20- vol%, 19.22-wt% brine, was inhibited more than 30°F over the pressure range studied, 500 to 4, 500 psig. In most cases, oil-based mud can be prepared with sufficient concentrations of dissolved solids to prevent gas-hydrates formation under downhole conditions. Mud samples should be tested to determine the temperature of gas-hydrates formation before field use.
Permeability Transects of Eolian Sands and Their Use in Generating Random Permeability Fields
Authors: Goggln D. J. , Chandler M. A. , Kocurek Gary , Lake Larry W. 
Published: December 2007

SummaryThis paper reports on observations derived from more than 10, 000 permeability measurements taken from eolian sands and their use in generating permeability fields for reservoir simulation input. Results show that classification and statistical measures of variability and spatial correlation (but not mean permeability) are portable between the outcrop and the subsurface.
Outcrop/Subsurface Comparisons of Heterogeneity in the San Andres Formation
Authors: Kittridge Mark G. , Lake Larry W. , Lucia F. Jerry , Fogg Graham E. 
Published: December 2007

Summary
An integrated outcrop and subsurface study of permeability variations in the San Andres formation demonstrates the extreme heterogeneity present in this economically important carbonate horizon. Permeability measurements were made with a field permeameter and were compared to subsurface core data. Geostatistical techniques were used to predict variability and scales of spatial correlation. Measured permeability showed substantial variability within units arranged in three correlation scales. Outcrop permeability data exhibited no marked permeability anisotropy in predicted spatial correlation length. Several scales of spatial variability have been observed in an outcrop section, with subsurface results in agreement.
Pore-Space Statistics and Capillary Pressure Curves From Volume-Controlled Porosimetry
Authors: Toledo Pedro G. , Scriven L. E. , Davis H. Ted 
Published: December 2007

SummaryFar more information about pore spaces of reservoir rock samples can be obtained from volume-controlled mercury porosimetry than from conventional pressure-controlled mercury porosimetry. Yuan and Swanson demonstrated this in landmark experiments with their apparatus for pore examination (APEX). With a mechanism-based, computer-facilitated model of pore-level displacement, we discover how much useful information about a porous medium can be extracted from volume-controlled mercury porosimetry. APEX mercury injection is quasistatic; so is our simulation. Displacements under this condition consist of smooth, reversible changes punctuated by jumps in capillary pressure, Pc, the sequence of which follows from the structure of the porous medium and the saturation history. Thus, careful examination of Pc fluctuations provides detailed information about pore-size distributions. The results account quantitatively for the APEX mercury Pc curves precisely measured by Yuan and Swanson. In our work, sample size—an aspect not reported previously—is a main factor in APEX response. Using Monte Carlo simulation, we find the optimum-sized specimen for examining a pore space with particular properties and investigate withdrawal experiments, withdrawal after partial reinjection, and full scanning loops.
Experimental Measurement of the Persistence of Permeability Reduction in Porous Media Treated With Xanthan/Cr(III) Gel Systems
Authors: Eggert R. W. , Willhite G. P. , Green D. W. 
Published: December 2007

Summary
A series of long-term experiments was conducted to determine the persistence of flow resistance in unconsolidated sandpacks treated with xanthan/Cr(m) gels. Gels were prepared with 2, 000 ppm xanthan and Cr(m) concentrations from 25 to 200 ppm. These systems exhibit various degrees of swelling or syneresis. The experiments were conducted by first allowing a gel to set up in a sandpack and then continuously flushing the sandpack with brine for up to 4 months at a constant pressure drop of 13.3 psi/ft. Flow rate was monitored to calculate permeability changes with time. Flow experiments indicated that the measurement of swelling and syneresis in bulk-gel tests is not a good predictor of gel response in unconsolidated sandpacks. Excellent permeability reduction was obtained in sandpacks when gels that exhibited 35% to 60% reduction in volume in bulk tests owing to syneresis were used. Gels were most effective at retaining flow resistance in the range of 35 to 75 ppm Cr(m), where the sandpacks regained &lt; 0.1 % of their original 4, 000 md permeability during the experiments. These observations were supported by experimens in which the pH of the injected brine was varied between 3.0 and 6.5. The swelling tests on the bulk gel indicated that permeability would decrease as pH increased and would increase as pH decreased. This occurred; however, the magnitude of the permeability change was less than inferred from bulk-gel measurements. Other experiments indicated that residual oil does not affect permeability modification in sandpacks. The amount of Cr(m) removed from the sandpack during brine flushing ranged from 38% for the 25-ppm-Cr(III) gel to 70% for the 200-ppm-Cr(III) gel. In all systems, effluent Cr(III) concentration declined exponentially as flushing continued, suggesting that the Cr(III) recovered never reacted with the polymer.
Pseudocomponent Selection for Compositional Simulation
Authors: Newley T. M. J. , Merrill R. C. 
Published: December 2007

Summary
This paper describes a scheme for combining the components in a multicomponent equation of state (EOS) into fewer components for compositional studies. The method is based on minimizing the difference between the Κ values of the original components and the Κ value of the pseudocomponent to which they are assigned. New rules to determine pseudocomponent properties are presented. The rules, based on K-value weighting, ensure that information about both coexisting phases is used in the derivation of pseudocritical temperatures and pressures. Results for the lumped models developed by this method are compared with the original multicomponent models. The method is shown to work for a variety of gas-condensate, miscibility, and gas-injection problems.
Water Tracing Enhances Miscible Pilot
Authors: Wood Kelvin N. , Li Francis S. , Heacock Dennis W. 
Published: December 2007

Summary
Radioisotope water tracers were used extensively during a produced-water preflush of the Redwater field hydrocarbon miscible pilot. The results from tracer injections in two zones in the original oil column of the reservoir provide convincing evidence of a preferred flow direction toward the southwest. In addition, they confirm the existence of communication across the shoal margin between foreslope and back reef facies and provide insight into the different flow characteristics inherent to the back reef and shoal margin. Excellent results were obtained with tritiated water (HTO) and cesium (Cs) tracers; cobalt (Co) tracer performance was poor, most likely because the formation retained the tracer. Summaries and discussions of these results, including an assessment of their effects on the pilot, are presented. The paper examines key factors that contribute to a successful tracing program and describes a wire-line tracer injection tool designed specifically for the project. No attempt is made to assess overall pilot performance because this work preceded the miscible flood.
The Use of the Effective-Medium Theory and a 3D Network Model To Predict Matrix Damage in Sandstone Formations
Authors: Khatlb Z. I. , Vitthal Sanjan 
Published: December 2007

SummaryThe size-matching technique and the effective-medium theory (EMT) were used to develop a model to predict the in-depth plugging of a formation core as a function of the solids particle size in the injection water. The pore-size distributions were determined with capillary pressure data [measured by the apparatus for pore examination (APEX)] rather than with the conventional capillary pressure curve. The morphology of the pore space was represented by a random 3D disordered network of pore bodies interconnected by pore throats. The absolute air permeability of the network was calculated with the EMT. The calculated permeabilities for Berea and Bentheim sandstones were compared with those calculated by the traditional bundle-of-capillary-tubes model and laboratory-measured values. A simple method is also presented that relates the ratio of plugged to unplugged pore throats to the loss in permeability for a given matching pore/particle-size criterion. With the three particle/pore-plugging criteria, the reduction in permeability caused by matrix plugging was closely predicted as a function of the median diameter of the injected solids for a given concentration.
Thermal Effects on Single-Well Chemical-Tracer Tests for Measuring Residual Oil Saturation
Authors: Park Y. J. , Deans H. A. , Tezduyar T. E. 
Published: December 2007

Summary
The single-well chemical-tracer (SWCT) test for measuring residual oil saturation, Sσr, often involves injecting cool fluid containing a reactive tracer into a warm formation. The Sor estimation with this method depends on the separation between reactant and product tracers. Because the reaction rate is temperature-dependent, accounting for the thermal effects may be necessary to obtain reliable results.
Two simulator models are normally used to interpret SWCT tests. The ideal model is used for relatively homogeneous sandstone formations. The pore-diffusion model is used for heterogeneous carbonate formations. Both models have now been solved with appropriate heat-balance equations. These nonisothermal models have been used to reinterpret several previously reported field tests. For the worst case, the estimated Sor value from the nonisothermal model is 5% PV higher than that from the isothermal model.
Inequality conditions have been developed that divide the parameter space of SWCT tests into two regions, depending on the location of the temperature front relative to the tracer bank during the reaction period. In the "safe" region, the estimated Sor values from isothermal and nonisothermal models are essentially equal. The inequality conditions have been extended to include the effects of over-and underburden layers and intervening shales in layered systems.
Foam Flow Through an Oil-Wet Porous Medium: A Laboratory Study
Authors: Sanchez J. M. , Hazlett R. D. 
Published: December 2007

Summary
A laboratory study of the steady generation and flow of gas and surfactant solution through an oil-wet porous medium indicates that foam is formed and is effective in reducing gas permeability. A comparison of the flow characteristics of foam in oil-wet and water-wet media showed that at similar surfactant concentrations gas permeability reduction in both systems is approximately equal. The ability to form stable foam in situ in an oil-wet porous medium appears to result from the alteration of the initially hydrophobic surface to hydrophilic by two mechanisms: surface tension reduction and surfactant adsorption. Wettability alteration of the hydrophobic surface is evidenced by a dramatic shift in liquid relative permeability when surfactant is present in the aqueous phase. The liquid relative permeability curve of the oil-wet porous medium, in the presence of surfactant, essentially matched that of the water-wet porous medium. Such shifts in liquid relative permeability have not been observed for foam flow in strongly water-wet porous media. No alteration in either liquid or gas relative permeability occurred with added surfactant when a residual mineral oil was present in the oil-wet system. Transient measurements, however, indicated the formation of foam in the water-wet system when residual oil was present.
Sampling Gas-Condensate Wells
Authors: McCain W. D. , Alexander R. A. 
Published: December 2007

Summary
The industry has a procedure for stabilizing and sampling retrograde-gas (gas-condensate) wells; however, no investigation of the quality of the samples resulting from this procedure has been published. During sampling, bottomhole flowing pressure (BHFP) typically is less than the dewpoint pressure of the original reservoir gas. This causes condensate liquid to build up in the reservoir around the wellbore. This paper presents the results of a study of the sampling procedure and of the buildup and stability of the condensate ring around the wellbore. A procedure designed to give the best chance of obtaining a representative sample is presented.
Reservoir Simulation on a Hypercube
Authors: Wheeler John A. , Smith Richard A. 
Published: December 2007

SummaryThe rapid evolution of parallel computers with distributed memory promises to reduce computer hardware costs by an order of magnitude. To examine the extent to which this promise can be realized in practice, we coded and tested a 3D parallel implicit reservoir simulator for an Intel iPSC/2™ hypercube with 16 vector processors. The simulator is based on an oil/water model and does not account for a gas phase. Test results were favorable. A correlation of computation efficiency with problem size and the number of processors demonstrates that up to 96% of the available CPU time on the hypercube can be used. Such high efficiencies were achieved by developing special algorithms well suited for multiple processors and distributed memory.
Factors Contributing to Cement Sheath Deposition in Casing Under Highly Deviated Well Conditions
Authors: Sabins F. L. , Smith R. C. , Broussard M. D. , Talbot K. J. , Olaussen S. R. 
Published: December 2007

Summary
Deposition of a cement sheath inside 9⅝-in. intermediate casings cemented in highly deviated North Sea wells often required reaming before drilling operations could be resumed. Attempts to remove or prevent solids deposition by means of additional wiper plugs, flushes, or flow-rate variation were ineffective and led to a laboratory investigation of the factors contributing to the cement sheath formation in highly deviated wells. The laboratory study was conducted in a large-scale cement-displacement test facility previously used in similar investigations to simulate field conditions in scale-model proportions with actual field operation pumping equipment, materials, and techniques. This paper describes the identification of cement sheath deposition through case histories, test facilities, conditions, and results and indicates a satisfactory resolution for this problem.
Foamed-Cement Characterization Under Downhole Conditions and Its Impact on Job Design
Authors: de Rozières Jean , Ferrière Rèmi 
Published: December 2007

Summary
The engineering properties of foamed-cement slurries were studied in detail with an original methodology based on new equipment. With this laboratory equipment, foamed cement can be mixed and characterized at pressures and temperatures representative of field conditions and at densities as low as 400 kg/m3. The pressure and shear field under which a foam is generated are found to have a strong effect on bubble-size distribution (BSD), permeability, and to a lesser extent, compressive strength. Data on thickening time, fluid loss, and the effect of temperature on foam properties are also presented.
A better understanding of foamed-cement properties allows optimization of job design so that prescribed pressure and density profiles in the column are achieved both during circulation and after placement. Critical design parameters are identified and their relative influence is shown through a case study.
Quality of Bentonite and Its Effect on Cement-Slurry Performance
Authors: Grant W. Hal , Rutledge John M. , Gardner Craig A. 
Published: December 2007

Summary
This paper shows the results of a 2-year study on the quality of cement-grade bentonite now available commercially. A comparison of laboratory-designed slurries with field-blend samples shows drastic alteration of cement-slurry performance from poor blending procedures and/or poor-quality bentonite, which could cause catastrophic consequences.
Evidence from microscopic examination, chemical-quality procedures, and cement-slurry performance data shows a failure rate approaching 50% among more than 150 samples tested from field stocks. Laboratory data on cement-slurry performance with bentonite that passed and failed the current API specification test are presented.
Case History: Ice Island Drilling Application and Well Considerations in Alaskan Beaufort Sea
Authors: Angell V. W. , Graham H. J. , Post G. J. 
Published: December 2007

Summary
During Winter 1988-89 Chevron U.S.A. Inc. and Mobil Oil Production Co. constructed an ice island with seawater spray to drill the Karluk prospect. A land-drilling program was modified to drill the exploration well to 11, 190 ft total depth (TD). The project was completed in the allotted time and within its budget, despite one of the most volatile winters on record.
Development of Lightweight Steel Drillpipe With a 165-ksi Yield Strength
Authors: Tsukano Yasushl , Ueno Masakatsu 
Published: December 2007

Summary
This paper describes the development of a lightweight steel drillpipe with a 165-ksi [1137-MPa] yield strength. The drill-pipe was developed according to three design objectives and verified by full-size and material-evaluation tests. The lightweight steel drillpipe has two advantages over standard API G-105 pipe with the same pipe-body OD—it weighs 25% less and has a 20% lower hydraulic loss (loss of fluid pressure)—but maintains a performance level comparable with that of G-105 pipe.
The Traveling-Cylinder Diagram: A Practical Tool for Collision Avoidance
Authors: Thorogood J. L. , Sawaryn S. J. 
Published: December 2007

SummaryThe "traveling-cylinder" diagram aids collision risk assessment during planning and collision avoidance during direc tional drilling at multiwell locations. Survey results can be plotted directly on the diagram, enabling an immediate visual risk assess ment. This paper describes the conceptual basis of the diagram, how the diagram is used during planning and drilling, and how the information on the diagram can be interpreted.
Radioactive Steam Tracer Comparison Between Krypton-85, Xenon-133, NaI-131 (Methyl Alcohol Based), and NaI-131 (Water Based)
Authors: Crowe Thomas L. 
Published: December 2007

Summary
Radioactive steam tracer surveys are run routinely in steam injection wells to check for tubing holes, packer leaks, open perforations, and steam migration behind casing. A field study comparing krypton-85, xenon-133, NaI-131 (methyl alcohol based), and NaI-131 (water based) was conducted to determine which radioactive tracers are the most accurate for these surveys. Testing showed that all tracers are accurate except NaI-131 (water based).
A New System for Controlling the Crosslinking Rate of Borate Fracturing Fluids
Authors: Cawiezel K. E. , Elbel J. L. 
Published: December 2007

Summary
This paper describes a delayed-crosslink activator system for borate fracturing fluids that allows crosslinking rates to be controlled to give low friction pressure in the wellbore. Data from laboratory development, full-scale friction tests, and fracturing treatments are included to illustrate the fluid properties and the ability to couple fluid performance with treatment design. Field case histories include friction-pressure data, which profile the changes that occur as the fluid is crosslinking at different stages in the tubing. Results indicate that different crosslinking rates can be recognized by their "friction-pressure signature" and that the crosslinking rate can be altered easily during a treatment to minimize total treating pressure. This technique, with its resulting friction pressure profile, has proved to be an extremely useful tool for field optimization of crosslink times.
Reactivity of San Andres Dolomite
Authors: Anderson Mary S. 
Published: December 2007

Summary
The San Andres formation is routinely stimulated with acid. Although numerous acidizing simulators are available to aid in treatment optimization, existing reactivity data were generated with quarried rock rather than formation samples. This paper presents reactivity data for five San Andres dolomite samples. These data can be used in most fracture-acidizing-design simulators to allow more accurate simulation of the acidizing process.
The Ford Geraldine Unit CO2 Flood— Update 1990
Authors: Pittaway K. R. , Rosato R. J. 
Published: December 2007

Summary
This paper updates the operating history of the tertiary CO2 flood in the Ramsey (Delaware sand) formation of the Ford Geraldine Unit (FGU). The discussion focuses on injection and production history, operational considerations, data collection and monitoring techniques, and plans for the flood.
Three-Phase Gas/Oil/Brine Relative Permeabilities Measured Under CO2 Flooding Conditions
Authors: Dria D. E. , Pope G. A. , Sepehrnoori Kamy 
Published: December 2007

SummarySteady-state three-phase gas/oil/brine relative permeabilities were measured in a carbonate core under CO2 flooding conditions. Results show that the relative permeability of each phase depends only on the saturation of that phase instead of on two saturations, as many previous studies have concluded. All previously reported gas/oil/brine relative permeability studies have been conducted with low-pressure N2 gas or air. In this work, CO2 gas, oil, and brine were injected into a carbonate core at 71°C and 9.65 MPa so that the phase behavior and flow would be similar to reservoir conditions. Results show that significant differences exist between the three-phase gas/oil/brine relative permeabilities measured when the gas is CO2 and those measured when the gas was N2.