bluuebunny/crossref_metadata_2025_split huggingface dataset:
Downhole Pneumatic Turbine Motors Testing and Simulation Results
Authors: Lyons William C. , Miska Stefan Z. , Johnson Philip W. 
Published: December 2007

Summary
A new motor was developed for use in air/gas drilling operations. Numerical simulation indicated that such a motor was feasible, and a prototype was built. The prototype underwent extensive bench testing and two successful field tests. The downhole pneumatic turbine drilling motor is expected to prove useful in directional drilling operations in areas where formation damage is a problem.
In-Situ Combustion Process Study With a Combined Experimental/Analytical Approach
Authors: Sibbald L. R. , Moore R. G. , Bennion D. W. 
Published: December 2007

Summary
Analysis of combustion-tube data produced from experiments performed under realistic reservoir conditions is currently the most valid method of investigating the in-situ combustion process. This paper describes an approach that uses a differential moving-frame descriptive model to analyze data from stabilized combustion processes produced in combustion-tube experiments. The approach is applied to a set of dry-air combustion runs. This study revealed consistent values for the fuel-combustion-reaction-kinetics parameters, showed that oxygen consumption was not confined to the high-temperature (300°C) combustion zone, and gave insight into the relationship between injected-gas flux and the distribution of energy liberation rate with implications for process stability.
Scaled Model Studies off CO2 Floods
Authors: Rojas G. A. , Zhu Tao , Dyer S. B. , Thomas Sara , Farouq All S. M. 
Published: December 2007

Summary
Immiscible CO2 floods with alternating water injection are promising for heavy-oil formations ill-suited for thermal treatment. This investigation uses scaled models to show that a 20% PV slug of CO2 can recover 5 to 50% of the oil in place (OIP), depending on the operating conditions. The CO2 requirement is small, &lt; 100 std m3/stock-tank m3.
Field Experiment of Lignosulfonate Preflushing for Surfactant Adsorption Reduction
Authors: Hong S. A. , Bae J. H. 
Published: December 2007

Summary
Lignosulfonate was field tested as a sacrificial adsorbate in conjunction with the ongoing Glenn Pool surfactant flood expansion project. A 2 wt% lignosulfonate solution was injected for 10 days as part of the preflush in this project. Results of the analyses of two observation well samples were interpreted for the effect of lignosulfonate on sulfonate adsorption and process performance. Even though the evidence was ambiguous, we concluded that the low-cost lignosulfonate preflushing was beneficial to surfactant flooding.
Analysis of Pressure-Buildup Data From a Well in a Multiwell System
Authors: Onur Mustafa , Serra Kelsen V. , Reynolds Albert C. 
Published: December 2007

Summary
This work investigates the buildup response of a well located in a system of producing wells completed in a closed, bounded reservoir. Using an analysis method based on the pressure derivative, we show that the drainage area of the well (at the instant of shut-in) and the flow-capacity (permeability-thickness) product can be computed directly from the derivative of pressure-buildup data even in cases where conventional semilog straight lines are not well defined. The analysis methods assume that the buildup-surveyed well has established its own drainage area before shut-in. For a system of wells located in a closed, bounded reservoir, this means that pseudo-steady-state flow prevails at the instant of shut-in. We also present a second method for estimating a well's drainage area from pressure-buildup data. The second method relies on the fact that during buildup, the well's shut-in pressure increases to a maximum and then decreases as a result of interference from neighboring producing wells. It is shown that the maximum shut-in pressure, and the time at which it occurs, often can also be used to compute the well's drainage area at the instant of shut-in and the average pressure in this drainage area.
Laboratory Measurements of Eleotrical Resistivity at Reservoir Conditions
Authors: Mahmood S. M. , Maerefat N. L. , Chang M-M. 
Published: December 2007

Summary
An experimental study to investigate the influence of variations in test conditions and laboratory procedures on the electrical properties of rocks is presented. Results suggest that the cementation and saturation exponents in Archie's equation should be determined in the laboratory at near-reservoir conditions to prevent an error of up to 8% from being introduced during the determination of water saturation.
Laboratory and Field Evaluation of a Combined Fluid-Loss-Control Additive and Gel Breaker for Fracturing Fluids
Authors: Cantu Lisa A. , Boyd Phil A. 
Published: December 2007

SummaryMore than 200% increase in fracture conductivity and permeability was obtained when a new degradable fluid-loss-control additive was used in place of silica flour (SF) in 40-lbm crosslinked hydroxypropyl-guar (HPG) fracturing-fluid systems. The new additive, an organic acid particulate (OAP), slowly degraded into water-soluble monomeric units at temperatures &gt; 150°F after fracture stimulation experiments. The high-acid-content degradation product then acted as an excellent HPG gel breaker and effectively cleaned the proppant packs.As a fluid-loss-control additive, the measured wall-building coefficients were as good as, or better than, those of SF in crosslinked-gel, linear-gel, and N2-foam systems. This paper summarizes a 2-year study of the evaluation and application of this new product in fracturing-fluid systems.
Simultaneous Wireline Operations From a Floating Rig With a Subsea Lubricator
Authors: Hopper Christopher T. 
Published: December 2007

Summary
In 1987, an extensive wireline program was completed on two subsea wells in the Highlander field in the central North Sea with a subsea lubricator deployed from a drilling rig that was drilling and working over adjacent wells. Working on two wells concurrently is a way to reduce the operating costs of a subsea development significantly.
A New Method To Predict Two-Phase Pressure Drop Across Perforations
Authors: Perez Godofredo , Kelkar B. G. 
Published: December 2007

Summary
Two-phase high-velocity dimensionless equations are derived to model the flow across the crushed zone of idealized perforated completions. The effects of GOR, perforation pressure, and size on pressure drop across perforations are investigated. A simplified form of the equations is proposed and used in the evaluation of a field test.
Characterizing Permeability Heterogeneity in Core Samples From Standard Miscible Displacement Experiments
Authors: Houseworth James E. 
Published: December 2007

Summary
Permeability heterogeneity in porous media is evaluated with standard-pressure and production-history measurements from miscible displacements. Variations in the production history with mobility ratio and deviations of the pressure history from an idealized response provide complementary information on permeability heterogeneity. These heterogeneity tests have been developed to assist in core sample selection for unsteady-state relative permeability tests and other transient displacement tests.
Modeling Reservoir Geometry With Irregular Grids
Authors: Helnemann Z. E. , Brand C. W. , Munka Margit , Chen Y. M. 
Published: December 2007

SummaryThis paper describes a practical method in which irregular or locally irregular grids are used in reservoir simulation with the advantages of flexible approximation of reservoir geometry and reduced grid-orientation effects. Finite-difference equations are derived from an integral formulation of the reservoir model equations equivalent to the commonly used differential equations. Integrating over gridblocks results in material-balance equations for each block. This leads to a finite-volume method that combines the advantages of finite-element methods (flexible grids) with those of finite-difference methods (intuitive interpretation of flow terms). Grid-orientation effects are investigated. For grids based on triangular elements, the more isotropic distribution of gridpoints diminishes the orientation effect significantly. Numerical examples show that the regions of interest in a reservoir can be simulated efficiently and that well flow can be represented accurately.
Relationship of the Volume-Balance Method of Compositional Simulation to the Newton-Raphson Method
Authors: Wong Terry W. , Firoozabadl Abbas , Aziz Khalld 
Published: December 2007

SummaryThis paper provides an analytical exposition of the relationship between two fully compositional, isothermal, three-phase, numerical simulator types in the literature. The Newton-Raphson (NR) method is based on the standard NR solution of the mass- or mole-conservation equations and associated constraints. The volume-balance (VB) method is based on the principle that, in each simulator block, the PV equals the combined fluid volume of all the phases. These two types of models have been regarded as different approaches to the same problem. An analytical demonstration, however, proves rather surprisingly that, although the two model types were developed from fundamentally different viewpoints (i.e., mass conservation vs. volume conservation), they lead to the same matrix system of the finite-difference equations. This understanding yields many advantages, including (1) methods to improve efficiency in both model types, (2) fully implicit and iterative forms of the VB model, (3) the assignation of physical meaning to groupings of terms from the NR Jacobian matrix, and (4) an understanding of how to decouple the mass- or mole-conservation equations from the thermodynamic equilibrium constraints. Also, a unified approach is possible that offers the best features of both simulation model types.
Modeling of Gravity-Imbibition and Gravity-Drainage Processes: Analytic and Numerical Solutions
Authors: Bech Niels , Jensen Ole K. , Nielsen Birger 
Published: December 2007

SummaryA matrix/fracture exchange model for a fractured reservoir simulator is described. Oil/water imbibition is obtained from a diffusion equation with water saturation as the dependent variable. Gas/oil gravity drainage and imbibition are calculated by taking into account the vertical saturation distribution in the matrix blocks.
Asphaltene Adsorption and Desorption From Mineral Surfaces
Authors: Dubey S. T. , Waxman M. H. 
Published: December 2007

Summary
This paper reports results of asphaltene adsorption/desorption on clay minerals, silica, and carbonates. It also describes the effect of adsorbed asphaltenes on rock wettability and a screening pyrolysis-flame-ionization-detection (P-FID) test to evaluate the ability of solvents to remove asphaltene from kaolin and formation core material.
Improved Demulsifier Chemistry: A Novel Approach in the Dehydration of Crude Oil
Authors: Staiss Friedrich , Böhm Roland , Kupfer Rainer 
Published: December 2007

Summary
With the ever-growing demand for more efficient dehydration and desalting of crude oil, classic demulsifiers no longer perform satisfactorily in most cases, and new chemical systems are required. This paper describes new emulsion breakers, generally polyester amines, and gives detailed laboratory studies of their advantages over classic demulsifiers: more complete migration to the interface, improved emulsion breaking and coalescence, improved effluent water quality, and partial corrosion inhibition. These new demulsifiers combined with classic emulsion breakers have been successfully tested.
Laboratory Study of Borehole Friction Factor With a Dynamic-Filtration Apparatus
Authors: Maidla Eric E. , Wojtanowicz Andrew K. 
Published: December 2007

Summary
This paper discusses a medium-scale borehole friction tester with dynamic-filtration capabilities that showed that friction coefficients are affected by mud quality, mudcake, and lubricant addition in low-solids, water-based muds (WBM's). Most measured values, including those from oil-based muds (OBM's), were between 0.2 and 0.3. This paper also reports on new effects of filter cake and solids deposition on borehole friction.
Phase Behavior of CO2/Hydrocarbon Systems: Amendments to Previously Predicted Phase Diagrams
Authors: Quiñones-Cisneros S. E. , Blackburn M. B. , Scriven L. E. , Davis H. T. 
Published: December 2007

Summary
In using the Peng-Robinson equation of state (PREOS) described by Sahimi et al., we found discrepancies with their results. By using two separate methods of computation, we deduced that their method is correct, but that some code or implementation errors must have caused the observed discrepancies.
Geochemical Monitoring of Drilling Fluids: A Powerful Tool To Forecast and Detect Formation Waters
Authors: Vuataz François-David , Brach Michel , Criaud Annie , Foulllac Christian 
Published: December 2007

SummaryThis paper describes a method based on the difference between the chemical compositions of formation and drilling fluids for analyzing drilling mud to forecast fluid-producing zones. The method was successfully applied in three boreholes in crystalline rocks in France. Subsequent geophysical logs and hydraulic tests confirmed the occurrence of flowing fractures.
Improved Steam-Foam Formulations: Concepts and Laboratory Results
Authors: Lau H. C. , Borchardt J. K. 
Published: December 2007

SummaryKern River pilot results show that a steam-foam formulation based on an alpha olefin sulfonate (AOS) containing 16 to 18 carbon atoms in the hydrocarbon chain improves sweep efficiency and oil recovery of the steamdrive but propagates relatively slowly and leaves the same residual oil saturation (ROS) as steam. Research has identified potentially superior formulations that form stronger foams, propagate faster, and/or reduce ROS below that to steam in the laboratory.
Transient Flow Behavior of Horizontal Wells: Pressure Drawdown and Buildup Analysis
Authors: Odeh Aziz S. , Babu D. K. 
Published: December 2007

Summary
Four flow periods may occur during the transient behavior of a horizontal well. Drawdown and buildup equations describing the flow behavior of each of the four flow periods are given. Methods for analyzing data obtained from testing the well to determine permeability anisotropy in its drainage volume and the skin factor are presented. Calculation procedures are illustrated by examples.
Formation Damage From Fine Particulate Invasion: An Example From the Lost Soldier Tensleep Formation
Authors: Rickford R. L. , Finney T. P. 
Published: December 2007

Summary
The Tensleep formation in the Lost Soldier field has been pattern waterflooded since 1976. Injection wells have historically exhibited large declines in injectivity and required frequent workovers. Because those declines were originally attributed to near-well damage from poor injection-water quality, a cleanup program was initiated that significantly reduced the amount and size of suspended particles in the injection water. Despite these improvements, injectivity continued to decline in many wells. Subsequent analyses of well histories, pressure-falloff tests, and reservoir petrophysical properties suggest that the reservoir damage in many instances was not only a sandface phenomenon, but also a result of deep particle invasion. Workover procedures were altered to treat the formation beyond the near-wellbore area, resulting in increased injectivities compared with the historical norm.
Causes of Blown Port Plugs
Authors: King G. E. , Packard B. R. 
Published: December 2007

Summary
After several incidents of blown port plugs in used and new perforating guns, a study was initiated to determine the causes of plug loss. The study included (1) an examination of the swelling characteristics of a heavy-wall, reusable perforating gun, (2) an examination of new guns from which plug loss had and had not occurred, and (3) construction of a port-plug test cell in which plug loss factors could be studied. The results of the study identified at least three major factors and nine minor factors that could operate singly or jointly to contribute to plug loss.
Transient Pressure Analysis of Horizontal Wells in Anisotropic Naturally Fractured Reservoirs
Authors: Agullera Roberto , Ng Michael C. 
Published: December 2007

Summary
Analytical solutions are presented for pressure-drawdown and -buildup analyses of horizontal wells in anisotropic reser voirs with tectonic, regional, or contractional natural fractures. (The reservoirs might be limited by parallel sealed boundaries.) These solutions have led to the identification of various flow periods, including radial in a vertical plane, transitional as a result of flow from the matrix into the fractures, linear when the transient pressure reaches the upper and lower boundaries of the reservoir, pseudoradial toward the wellbore in a horizontal plane, and linear when the transient reaches the outer parallel boundaries. Recognition of these flow periods leads to the calculation of pi or p*; permeabilities in the x, y, and z directions; storativity ratio, ω; average distance be tween natural fractures; fracture porosity; and fracture aperture, skin, and pseudoskin caused by vertical and horizontal partial penetra tion. Calculations are illustrated with an example.
Travis Peak Core Permeability and Porosity Relationships at Reservoir Stress
Authors: Luffel D. L. , Howard W. E. , Hunt E. R. 
Published: December 2007

SummaryRelationships of permeability to porosity are shown from analyses of more than 2, 100 core plugs from nine wells in the Travis Peak, a low-permeability, tight-gas sandstone formation in northeast Texas. Effects of reservoir vs. ambient stress are shown for permeability, porosity, and the Klinkenberg factor. The relationship of brine permeability to gas permeability is also shown.
Geometric Concerns for Accurate Measurement of Capillary Pressure Relationships With Centrifuge Methods
Authors: Christiansen Richard L. 
Published: December 2007

Summary
Accuracy of capillary pressure relationships obtained from centrifuge experiments is widely recognized to depend on the quality of raw data, the homogeneity of the rock sample, and the methods used for data reduction. However, the systematic error caused by the radial nature of centrifugal fields is not widely recognized. This paper shows that this radial error can be greater than errors caused by poor data-reduction methods. The radial error can be estimated from the geometry of centrifuge rotors and rock sample dimensions. Careful experimental technique can minimize radial error. Furthermore, data-reduction methods can eliminate radial error by properly accounting for the radial nature of centrifugal fields.
Surveying Techniques With a Solid-State Magnetic Multishot Device
Authors: Thorogood John L. , Knott David R. 
Published: December 2007

Summary
An electronic magnetic multishot instrument was introduced in 1985 to overcome accuracy and reliability limitations associated with conventional photomechanical multishot systems. This paper describes the survey system and the instrument's performance capabilities. Our aim is to develop a tool-performance model for general application to the management of surveying operations. Accuracy is considered in two parts: sensor errors are considered in detail, and external effects on accuracy—e.g., axial misalignment, bottom-hole-assembly (BHA) deflection, geomagnetic influences, and drillstring-induced interference—are analyzed and quantified. We found that geomagnetic influences and drillstring-induced interference dominate the ultimate performance of all magnetic tools, particularly this electronic multishot instrument. This paper also describes "in-hole referencing, " a method of eliminating these errors that involves surveying the first part of an openhole section with a high-accuracy gyroscope and aligning data derived from subsequent magnetic surveys with it. Using this method, we can achieve gyroscope-survey levels of accuracy with magnetic instruments in highly deviated and extended-reach wells without incurring the costs and penalties of running wireline surveys.
Pressure-Transient Analysis for a Slanted Well in a Reservoir With Vertical Pressure Support
Authors: Abbaszadeh Maghsood , Hegeman Peter S. 
Published: December 2007

SummaryAnalytical solutions are presented for the pressure response of a slanted limited-entry well in an infinite reservoir subject to pressure support from a gas cap, bottomwater drive, or a combination of both. The well's inclination angle ranges from 0 to 90°, covering vertical and horizontal wells as limiting cases. An interpretation method based on nonlinear regression provides a useful analysis procedure for well tests from such reservoirs. The pressure support from the gas cap or bottomwater often masks the late-time reservoir features, making conventional semilog analysis difficult. Field tests are interpreted to illustrate the applicability and limitations of the regression method.
The Underwater Production System
Authors: O'Brien E. J. , Hetiand Torger 
Published: December 2007

Summary
The underwater production system (UPS) is a subsea hydrocarbon production system developed jointly by Statoil and Mobil Exploration Norway Inc. through a project team based in Trondheim, Norway. This paper describes the system and the key development activities that led to the project goal of a fully developed system design.
Formation Damage Caused by Cement Filtrates in Sandstone Cores
Authors: Yang X. M. , Sharma Mukul M. 
Published: December 2007

Summary
A series of core damage experiments was conducted with filtrates containing various cement additives, such as dispersants and fluid-loss additives. Results clearly show that the extent and location of the permeability impairment varies, depending on the relative rate of particle precipitation and the residence time in the core. Results of the core-flow experiments are interpreted in conjunction with particle-size distribution and concentration results obtained in batch experiments. Variations in the average particle size and the number concentration of particles with time in various compositions of cement filtrates are reported. These prove to be useful indicators of the extent and location of the damage observed in the cores.
A User's Approach to Qualification of Dynamic Seals for Sour-Gas Environments
Authors: Abrams Philip I. , Kennelley Kevin J. , Johnson Dale V. 
Published: December 2007

Summary
The selection and performance of dynamic-seal materials for use in aggressive, subsurface, sour-gas environments have often been unsuccessful and resulted in costly field failures. Seal performance is adversely affected by H2S, CO2, high temperature, corrosion inhibitors, and dynamic movement. Standard laboratory test methods to evaluate elastomeric materials for subsurface sealing applications have not allowed reliable prediction of seal behavior in actual field service. This paper presents a new and unique test apparatus that can be used to evaluate dynamic-seal materials and to qualify entire seal-stack configurations for subsurface sour-gas environments.
The Dynamic Two-Fluid Model OLGA: Theory and Application
Authors: Bendlksen Kjell H. , Malnes Dag , Moe Randl , Nuland Sven 
Published: December 2007

Summary
Dynamic two-fluid models have found a wide range of application in the simulation of two-phase-flow systems, particularly for the analysis of steam/water flow in the core of a nuclear reactor. Until quite recently, however, very few attempts have been made to use such models in the simulation of two-phase oil and gas flow in pipelines. This paper presents a dynamic two-fluid model, OLGA, in detail, stressing the basic equations and the two-fluid models applied. Predictions of steady-state pressure drop, liquid holdup, and flow-regime transitions are compared with data from the SINTEF Two-Phase Flow Laboratory and from the literature. Comparisons with evaluated field data are also presented.