bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fractional-Flow Model for High-pH Flooding
Authors: Ramakrishnan T. S. , Wasan D. T. 
Published: December 2007

Summary
A model based on the fractional-flow theory is developed for the enhanced recovery of acidic crude oil with caustic as the alkaline agent. The model incorporates earlier work on fluid/fluid interactions of acidic-crude-oil/caustic systems, which provides not only the chemical reaction equilibria but also the interfacial tension (IFT) as a function of composition. The lowering of IFT as a result of in-situ-generated surface-active agent enhances the viscous-to-capillary-force ratio, which is presumed to be the cause of the alteration in relative mobilities of oleic and aqueous phases. The complete set of species-conservation equations forms a system of three quasilinear partial-differential equations that is reducible in the generalized sense. The system is solved by the method of generalized Riemann invariants. The effect of such parameters as viscosity ratio, reference capillary number, injected fluid pH, and salinity is computed with properties of Long Beach crude. New features that arise from the influence of the optimum region when an overoptimum composition is injected are identified. On the basis of composition paths, it is shown that the optimum regions play a dominant role in the process and that the IFT between the injected solution and the crude has no direct bearing on ultimate oil recovery. Simple graphic procedures that afford quick construction of solutions are shown to be possible.
An Update of the Polymer-Augmented Alkaline Flood at the Isenhour Unit, Sublette County, Wyoming
Authors: Doll Thomas E. 
Published: December 2007

SummaryAn Almy sand polymer-augmented alkaline flood at the Isenhour Unit, Sublette County, WY, is reviewed. This paper updates process technology, including the use of clay stabilization, sweep improvement, soda ash alkaline agent [to reduce interfacial tension (IFT) and mobilize residual oil], and anionic-polymer-blend mobility buffer. Oil production has been increasing at 20%/yr since the process start.
Drilling With a One-Step Solids-Control Technique
Authors: Hayatdavoudi A. 
Published: December 2007

Summary
The objectives of this paper are to report a new philosophy in solids control and field practice, referred to as fluid conditioning, to make a comparative evaluation of surface solids-control equipment, and to show details of a comprehensive mineralogical and physicochemical analysis of removed solids.
For brevity, only a few field results are emphasized. For example, in a weighted mud system of 15.2 lbm/gal [18.2 × 102 kg/cm3], the adjustable concentric device of fluid conditioner rejects a greater percentage of 0.5- to 1.0-μm solids than a centrifuge. In an unweighted mud system of 9.5 lbm/gal [11.4 × 102 kg/m3], fluid contaminants such as calcite, dolomite, and salt are rejected through underflow. Another field example based on microscopic and scanning electron microscopic (SEM) size analysis showed that in a 12-lbm/gal [14.4 × 102-kg/m3] mud system, it is necessary to increase the operating pressure by a few psi to reduce the amount of 6-μm material.
Our research in the area of particle size analysis of small, oilfield particles—e.g., smectite, sepiolite, Wyoming bentonite, and barite from bags of dust collectors—reveals that a quick-fix Fraunhofer diffraction analysis in the range of 10 μm and less is totally invalid in quantitative works.
Finally, through the analysis of fluid rejects, we concluded that after the rig shaker (assuming that the rig shaker performs well), the one-step solids-control fluid conditioning can deliver desirable rheological properties and a reasonable size range for the suspended material.
Ultra-High-Pressure Tubing-Retrievable Annular Safety Valve
Authors: Morris A. J. , Pringle R. E. 
Published: December 2007

Summary
Ultra-high-pressure (15,000- to 20,000-psi [103.4- to 137.9-MPa] working pressure), deep, hot gas well completion techniques currently have limited capabilities. Environments encountered at these pressures normally have H2S concentrations of 5% or more at temperatures higher than 400°F [204°C] with CO2 also present.
Using new metal sealing technology recently developed for tubing-retrievable safety valves for ultra-high-pressure production service1 combined with a casing polished-bore-receptacle (PBR) concept provides a simple solution in total well control. This annular-control safety valve is placed in the PBR as an integral part of the production string, complemented by a tubing-mounted safety valve for tubing-production control. Both valves are operated by hydraulic control lines to the surface as in standard safety-valve operations.
Reverse Combustion - A New Oil Recovery Technique
Authors: Perry Robert H. , Green Don W. , Campbell John M. 
Published: December 2007

Although the broad recovery method known as underground combustion embodies many related techniques, principle attention has been focused on alternatives known as "forward" and "reverse" combustion. Summaries follow in this issue for three Technical Publications on reverse combustion, and it is the purpose of this article to briefly review in situ combustion and to introduce the subject of reverse combustion.
Secondary recovery by underground combustion is a most intriguing method which provides energy and material transport through porous media. The "heat wave" effectively reduces the viscosity of the driven oil and thus, for many crudes, dramatically increases its fluidity. The material transport ahead of the heat wave acts as a miscible fluid drive. The result is a very efficient sweep of residual oil from the area.
Our fundamental knowledge about the process is limited, however, except in a general way; thus, detailed engineering recommendations are difficult. It must be remembered that exceedingly complex cases of multiphase fluid flow, multi-dimensional and multi-mechanistic heat transfer, heterogeneously catalyzed reaction kinetics, and multi-component phase equilibria are all combined in this process in a mutually dependent manner. It is no wonder that our scientists have barely scratched the surface in understanding the in situ combustion process.
Both forward and reverse combustions utilize as fuel the residual coke from the in-place oil. The difference between the techniques is whether the flame front and material flow are in the same direction (forward combustion) or in opposite directions (reverse combustion). A simple analogy may be used to clarify the difference.
Picture yourself smoking a cigarette in the conventional manner. The flame front and the products of combustion both travel toward your mouth (forward combustion). If you blow into the cigarette, however, the products of combustion travel outward while the flame front still moves toward your mouth (reverse combustion). Thus, in forward combustion both oil and the heated zone are moving toward the producing well and away from the injection well, while in reverse combustion the flame front moves away from the producing well.
Unsteady-State Distributions of Fluid Compositions in Two-Phase Oil Reservoirs Undergoing Gas Injection
Authors: McFarlane Robert C. , Mueller T.D. , Miller F.G. 
Published: December 2007

Abstract
During the process of gas storage in pressure-depleted oil reservoirs, it has been observed that in some instances additional liquid oil is recovered and that the composition of the storage gas is materially altered. A mathematical study was made of the dynamic behavior of such a depleted oil reservoir undergoing gas injection. The important variable considered in this study, not included in previously published work, was that of compositional effects on the phase behavior of two-phase flow. Pressure, saturation and component composition profiles were developed for a linear, horizontal and homogeneous porous medium containing oil and gas but undergoing dry gas injection. Special new techniques were developed to overcome the problems of numerical smoothing which arise in the solution of the equations representing such systems.
The method of solution includes the development of partial differential equations describing the behavior of the system, representing these equations by finite difference approximations, making certain simplifying assumptions and, finally, applying methods of numerical analysis with the aid of a high-speed digital computer.
In an example calculation, results using the mathematical model are compared with field observations made on a gas storage project in Clay County, Tex. This field project involved a depleted oil reservoir used' for gas storage and gas cycling purposes. As a result of these processes, the reservoir yielded substantial amounts of secondary oil, both in the form of stock tank oil and as vaporized products in the produced gas. The methods derived in this study may be applied to a variety of oil reservoir problems which are dependent on compositional effects.

INTRODUCTION
In recent years the number of oil reservoirs being used for gas storage purposes has increased greatly, and there has been at least one published account of additional oil recovery resulting from gas cycling a depleted oil reservoir after repressuring with dry gas for storage purposes. Additional oil recovery from oil reservoirs resulting from gas storage operations could become an important secondary recovery process. This is especially true since the use of natural gas in large metropolitan areas continues to increase and more gas storage volume near these areas is needed.
These facts provided the motivation for the work reported here. This paper reports on a study of the inter-relations of composition, saturation and pressure changes which occur when hydrocarbon gas is injected into an oil reservoir system. From an understanding of the process, prediction methods may be developed for use in forecasting the secondary recovery products from gas storage operations in oil reservoirs and, consequently, .the economics of such projects can be developed.
Completion Design for Waterfloods and CO2 Floods
Authors: Stone P. C. , Steinberg B. G. , Goodson J. E. 
Published: December 2007

Summary
A completion design is used to complete a well for production or injection operations. It comprises the planned wellhead, tubing and casing, downhole equipment, and treatment (chemical or stimulation). This paper examines the criteria for selection of tubing and downhole equipment used in waterflood and CO2-flood completions. This paper reviews corrosion problems, material options, commonly used packers/accessories, and the influence of CO2 injection on the selection process.
Borehole Televiewer Improves Completion Results in a Permian Basin San Andres Reservoir
Authors: Clerke E. A. , Van Akkeren T. J. 
Published: December 2007

Summary
The borehole televiewer (BHTV) is an acoustic logging tool that has a fine vertical resolution (⅓ in. [8.5 mm]) that is extremely useful for detecting bedding orientation, thin high-permeability zones, lithology changes, and zones of secondary or vuggy porosity. BHTV logs were acquired from 10 wells during the recent infill drilling of the North Hobbs (Grayburg/San Andres) Unit. These logs, when correlated with conventional logs and core data, have improved completion strategies, resulting in higher oil and lower water production in new infill wells.
Applications of Nuclear Science in Petroleum Production
Authors: Williams Milton 
Published: December 2007

Introduction
To aid in solving the many problems with which it is faced, the petroleum industry long has been accustomed to rely on the research which it conducts at its own expense and to adapt to its particular needs the results of research which originates in other fields. Just as it has been able to put to its own uses many other scientific advances, so the petroleum industry has drawn freely on developments in nuclear science to provide new tools, methods and knowledge designed to aid in the search for petroleum and in the production of oil and gas.
At the outset, it must be understood that, to date, there has been no application of nuclear science which may be said to have revolutionized the petroleum industry's operations. It is true, however, that nuclear science has made numerous, distinct contributions to the industry in a number of ways and that this multiplicity of applications represents, in the aggregate, a very real advance.

Geochronology
Illustrative of the way in which developments in nuclear science can be of benefit in petroleum exploration is the application of age-dating to the sediments drilled in the search for petroleum.
Since the early days of radioactivity, there has been an interest on the part of the geologist in dating strata in an absolute chronology by use of various radioactivity decay schemes. Joly, Rutherford, and their contemporaries laid the ground-work many years ago by use of uranium-lead, thorium-lead and uranium-helium methods in which the relative amounts of "parent" and of "daughter" were determined by chemical analysis alone. As the years have passed, more decay systems have been exploited, and more highly sophisticated methods have been brought to bear on the accurate determinations of parent and daughter which are required for precise dating. Today, there is a wealth of literature on the subject, and additional research is being carried out in many places which is designed to make more accurate the determination of age.
Prediction of the Minimum Miscibility Pressure of a Vaporizing Gas Drive
Authors: Nouar A. , Flock D. L. 
Published: December 2007

Summary
A method is proposed to estimate the minimum miscibility pressure (MMP), pmm, of a vaporizing gas drive with a lean hydrocarbon gas on the basis of the thermodynamic properties of the displacing and displaced fluids. The determination of pmm is based on the phase behavior of the system of fluids considered. Thermodynamic criteria have been set forth for the case of ternary systems. The method is very easy to use and is intended for the case of a vaporizing gas drive by a very lean hydrocarbon gas—i.e., composed principally of methane.
Measurements and Correlations of the Physical Properties of CO2-Heavy Crude Oil Mixtures
Authors: Chung Frank T.H. , Jones Ray A. , Nguyen Hai T. 
Published: December 2007

Summary
Viscosity reduction and swelling are the principal mechanisms contributed to the improvement of heavy-oil recovery by immiscible CO2 displacement. This paper presents the results of experimental measurements for the physical properties of heavy oils before and after CO2 saturation. Based on measured data, correlations were developed for the predictions of CO2 solubility, oil swelling factor, and viscosity change for CO2-saturated heavy oils.
Interpretation of Radioactive Tracer Results in a Steamdrive Project
Authors: Heisler Robert P. 
Published: December 2007

Summary
Reservoir radioactive tracer programs have historically been viewed as obtaining speculative reservoir information because of the low recovery efficiencies of the injected isotopes. This case study presents the results of a steamdrive, multi-isotope program that recovers as much as 50% of the injected radioactivity. The ability to trace both the steam and liquid water phases simultaneously, at high concentrations, enables a material balance to be performed on the isotopes. The resultant interpretation quantifies the developed interwell communication and steam zone sizes while qualitatively providing an appreciation of the control that well operations have on reservoir fluid movements.
Prediction of Slug Length in Horizontal, Large-Diameter Pipes
Authors: Scott Stuart L. , Shoham Ovadia , Brill James P. 
Published: December 2007

Summary
The prediction of slug characteristics for large-diameter pipes is studied with data collected from flowlines in the Prudhoe Bay field in Alaska. A 3-mile [5-km] -long pipeline was fully instrumented with nuclear densitometers, insert turbine meters, flowmeters, pressure and temperature sensors, and separator level indicators. During these tests, more than 19 million data points were collected on 12-, 16-, 20-, and 24-in. [30-, 41-, 51-, and 61-cm] -diameter pipes. These data were used to construct a data base that can be accessed interactively or by FORTRAN applications programs. The data show such slug characteristics as slug length, bubble length, and holdups. Data analysis revealed that the liquid slugs do not maintain a constant length and that the slugs tend to grow as they flow through the pipeline. An existing slug-length correlation was modified with these new data, and a term was added to account for the observed slug growth.
An Improved Streamline-Generating Technique That Uses the Boundary (Integral) Element Method
Authors: Numbere D. T. , Tlab D. 
Published: December 2007

Summary
The boundary element method (BEM) has been used to generate streamlines for homogeneous and sectionally homogeneous reservoirs having irregular boundaries. This technique is superior to earlier methods that use "image wells" to simulate the reservoir boundary, especially for cases where the reservoir boundary is irregularly shaped. It has wider applicability to different kinds of reservoirs and eliminates the need for trial-and-error solutions. The errors caused by discretization and numerical approximation arise on and adjacent to the boundaries only, therefore the pressures and pressure gradients on which the streamlines are derived can be calculated with very high accuracy in the interior of the reservoir. Thus, the streamlines generated with this method are expected to be more realistic and representative of the actual physical system.
Study of Multiphase Critical Flow Through Wellhead Chokes
Authors: Surbey D. W. , Kelkar B. G. , Brill J. P. 
Published: December 2007

SummaryUse of wellhead chokes to monitor and control well flow rates and to protect the reservoir from surface pressure fluctuations is quite common. This study investigates the use of multiple-orifice-valve (MOV) chokes in the critical-flow region.Experimental data collected for a high-pressure air/water system show that conventional relationships are not successful in analyzing the experimental data for MOV chokes. A new relationship based on the sonic velocity of two-phase homogeneous mixtures is developed for the prediction of the critical-flow transition. The procedure uses choking, rather than liquid sonic velocity, as the criterion for critical flow in the liquid phase. The procedure is iterative but compensates for its complexity with high reliability and generality. The new relationship is validated by experimental data.
Fines Migration, Blocking, and Clay Swelling of Potential Geothermal Sandstone Reservoirs, Denmark
Authors: Priisholm S. , Nielsen B. L. , Haslund O. 
Published: December 2007

Summary
Medium-grained, moderately well-sorted sandstones of fluvio-deltaic to shallow marine origin have been investigated for fines production and for variations in porosity/permeability. Porosity and permeability change within small horizontal and vertical changes in sampling points. Also, air permeability depends on flow direction, Klinkenberg correction, and cleaning procedure. Kinkenberg-corrected permeability and brine permeability were found not to be comparable.
Brine flow caused fines of kaolinite and quartz to be produced from the compacted sandstones, while uncompacted sandstones produced kaolinite, illite, and detrital minerals. Chlorites and mixed-layer clays were not produced as fines, although they were present in some samples. Reservoir damage occurred when formation brine was replaced by KCl-brine, at increase in flow velocity, and at pauses in flow. Changes in flow direction caused severe fines production, renewed bridging, and blocking by fines. Severe damage occurred when the samples were flushed with deionized water. Compared to field experiments, the laboratory experiments give the worst case of damage. An inverse relation was noted between porosity and the amount of fines produced.
Microbit Studies of the Effect of Fluid Properties and Hydraulics on Drilling Rate
Authors: Eckel John R. 
Published: December 2007

Abstract
It has long been known that mud properties affect drilling rate and that drilling with water is as much as six to seven times faster than with mud. However, it is not known why drilling rates with mud are lower. Recent studies show what fluid properties govern microbit drilling rate and also provide a quantitative correlation of these fluid properties and hydraulics with microbit drilling rate. All the microbit tests reported in this paper were made with a low permeability (about 10 md) limestone. They were conducted at constant bit weight and rotary speed with varying fluid properties, flow rate Q and nozzle diameter d. The tests showed that
- drilling rate in a given system with constant circulating rate and nozzle velocity is a function of the kinematic viscosity [viscosity/density, (cp)/ p (density)] of the drilling fluid measured at near bit nozzle shear rates;
- the combined effect of fluid properties and hydraulics on microbit drilling rate is defined by a Reynolds number function (kQp/D );
- for the same kinematic viscosity, drilling rate is independent of solids content; and
- for the same kinematic viscosity, drilling rate is independent of fluid loss.

Introduction
The fact that mudding up reduces rate of penetration is well known, but the reduction varies from well to well. The rate with mud may be 80 percent of the water rate or it may be as low as 15 percent Since this reduction of up to seven-fold takes place under conditions of constant bit weight, rotary speed and mud circulating rate in a uniform formation, it can only be a result of the change in fluid properties. Previous work (both in field tests and in laboratory microbit tests) showed that drilling rate with mud is lower than with water (Figs. 1 and 2). Microbit tests also confirm, at least qualitatively, the field observation that drilling rate slows with increased pressure differential from borehole to formation (Fig. 3). The qualitative effect of drilling rate of bit weight, rotary speed and rate of mud circulation are also the same for the field and microbit rig. For these reasons, the industry generally accepts microbit results as being qualitatively meaningful in terms of field application.
An Analytical Study of Pseudotime for Pressure Drawdown in a Gas Reservoir
Authors: Finjord Jan 
Published: December 2007

Summary
The pseudotime transformation in the diffusion equation for pseudopressure is studied analytically for drawdown in a gas reservoir. The equation is not effectively linearized for early drawdown in the infinite-acting period because correction terms in the transformed equation cannot generally be neglected compared with terms interpreted as giving rise to liquid-type behavior. The remaining possibility of approximately logarithmic solutions in pseudotime is considered with slope differing from the liquid-type value. Analytical estimates for the magnitude of correction terms and for deviation of approximate slope are given.
A Numerical Study of the Pseudotime Transformation for Drawdown in the Infinite-Acting Period
Authors: Yue-lu You , Finjord Jan 
Published: December 2007

Summary
Drawdown with a constant-surface-conditions gas rate into a single well, starting at homogeneous pressure conditions in a cylindrical gas reservoir, is simulated numerically. For radii much larger than the wellbore radius, the pseudopressure solution in the infinite-acting period can be plotted uniquely as a function of a Boltzmann variable s=rD2/4tpD, where rD and tpD are dimensionless radius and pseudotime. The nonlinear correction terms in the pseudotime diffusion equation, far from being negligible for drawdown, can become dominant in the infinite-acting period. This confirms an analytical result obtained previously. The correction terms are shown by simulation to be functions of s only for radii much larger than the wellbore radius. Plotted vs. In s, the pseudopressure shows an approximately linear behavior with a slope slightly larger than the usual constant-diffusivity slope. This was predicted by an explicit analytical solution.