bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measuring Well Injection Profiles of Polymer-Containing Fluids
Authors: Bragg J. R. , Roesner R. E. , Strassner J. E. 
Published: December 2007

Abstract
Determining injection flow profiles for various injected fluids was part of the surveillance program for monitoring the performance of Exxon's surfactant flood pilot test recently conducted in the Loudon Field, Fayette County, Illinois. Injection profiles for brine, microemulsion, and polymer drive water were measured using a radioactive tracer flow log. Profiles measured for brine injected prior to the microemulsion flood were in reasonable agreement with absolute permeability profiles determined by core analysis. However, for microemulsion injected in these same intervals, the profiles were found to be erroneous and completely misleading. For the viscous microemulsion, the profiles consistently indicated that all injected fluid was entering the upper one foot of the 13-foot-thick open-hole sandstone interval, thus suggesting the existence of horizontal fractures.
Poor dispersion of the radioactive tracer in the viscous microemulsion was believed to be responsible for the anomalous responses. To study the performance of the tracer flow log tool in water and in viscous solutions containing polymer, tests were performed in a visual flow loop using colored dye as a substitute for the radioactive tracer. Results confirmed that the tracer ejection system of the conventional tool usually ejected the tracer directly onto the casing wall where the velocity was substantially less than the average fluid velocity in the casing-tool annulus. When the flowing fluid was water, the turbulent jet of ejected tracer rebounded from the casing wall and was dispersed. However, when the fluid contained polymer, viscous laminar flow dampened dispersion of the tracer and retained it near the pipe wall, thus causing the interpreted flow rate to be essentially near zero.
To mitigate this problem, the ejection system of the tool was modified to allow tracer to be ejected closer to the center of the casing-tool annulus where the tracer velocity would be in better agreement with the average fluid velocity. A modified tracer flow log was subsequently used to redetermine injection profiles for microemulsion and polymer drive fluid in the Loudon pilot wells. Profiles measured by this modified tool were in reasonable agreement with profiles measured earlier for brine injection and with profiles of absolute permeability from core data.
Results of these experiments therefore show that injection profiles for viscous fluids measured by a conventional radioactive tracer flow log are likely to be unreliable. However, the log tool can be modified to provide reasonable results.
Applicability of Water Shutoff Treatment for Horizontal Wells in Heavy-Oil Reservoirs
Authors: Verre Francesco , Blunt Martin , Morrison Alan , McGarva Tony 
Published: December 2007

AbstractThe applicability of water shut-off treatment for horizontal wells in heavy oil reservoirs is analyzed in this study considering two different treatments: inorganic gel and relative permeability modifier (RPM).In the first part of this paper, a general description of heavy oil reservoirs behavior is given, investigating the suitability of the treatment for this type of reservoir. The analysis is then applied to a real case, the Captain field. Captain is a heavy oil, largely homogeneous reservoir exploited with horizontal wells. Due to the presence of many production wells with high water cut, it has been considered a candidate for a water shut-off pilot project. Six different scenarios in a simulation study were considered with the reservoir properties of Captain in order to test the effectiveness of the treatment on production wells. These are typical producer/injector configurations found in a heavy oil field exploited with horizontal wells.The aim is to analyze different water production mechanisms and evaluate the effectiveness of the treatment under different reservoir conditions. The influence of injection rate, oil viscosity, treatment of the injector and polymer adsorption were also investigated.The study showed that the water production mechanism has a strong influence on the effectiveness of water shut-off treatment. In particular, water coning in heavy oil reservoirs can be effectively treated with gel if it is applied to the entire section of the well. Noteworthy is the effect of permeability variations: with lower kv/kh ratios it is possible to achieve a preferential path for treatment injection delaying effectively the water coming from a lateral injector/aquifer rather than from the water cone. Polymer adsorption has a negative influence on performance for high permeable zones. The treatment is not effective for low water cut wells, low oil viscosities and it is not suitable for injection wells.
Numerically Derived Type Curves for Assessing Matrix Recovery Factors
Authors: Pirker Barbara , Mittermeir Georg M. , Heinemann Zoltán E. 
Published: December 2007

Abstract
This paper presents a methodology for creating and running single matrix block models with a reservoir simulator. The small cell sizes lead to numerical problems that were successfully solved. Additionally recovery curves derived from numerous simulation runs under varying reservoir conditions are presented. These curves enable estimating matrix recoveries without running a simulation by only defining rock type and production conditions.
The investigations are based on undersaturated oil produced by water displacement. Imbibition forces, gravity drainage and capillary continuity are allowed for. Emphasis is put on the influence of wettability, matrix shape factor and permeability on recovery.
The common approach for simulating naturally fractured reservoirs is the dual continuum concept. Not so for the single matrix block model, in which a matrix block and the surrounding fractures are discretized by gird cells. The size of the resulting grid model equals the extensions of a matrix block described by the shape factor in a dual continuum simulation model.
Representing both the fracture and the matrix by grid cells makes a matrix-fracture transfer function obsolete, enabling a detailed investigation of matrix-fracture interaction. Consequently, numerical transfer functions and correlations for assessing recovery factors can be derived for certain reservoir conditions.
Naturally fractured reservoirs are a challenging task for the E&P industry for old and new oil fields. Many of the newly developed reservoirs happen to be fractured and therefore they are becoming more and more subject of extensive studies. In such systems most of the oil is stored in matrix blocks acting as fluid sources/sinks to the surrounding fracture planes in which fluid transport and production/injection takes place. Consequently, the matrix recovery factor is of special interest, and efficient and accurate methods to estimate the matrix depletion efficiency and matrix-fracture interaction should be found.
A New Polymer for Enhanced Oil Recovery
Authors: Bauer Richard G. , Klemmensen Daniel F. 
Published: December 2007

Abstract
A new water soluble acrylic polymer has been developed for use as a mobility control agent in enhanced oil recovery. This polymer was designed to meet the fundamental requirements for a mobility control application, including cost effectiveness, stability to mechanical shear, non-plugging in porous media, demonstrable tertiary oil recovery, stability in the presence of salts and chemicals, and retention of viscosity after extended exposure to elevated temperatures. This polymer has been extensively tested in the laboratory and compared to existing mobility control polymers, such as partially hydrolyzed polyacrylamides and polysaccharides. One of the major attributes that this polymer demonstrated was a retention of viscosity after extended aging at elevated temperatures in various media, including high brine conditions.
Laboratory core floods have shown this polymer to be equally effective in tertiary oil recovery in both polymer-augmented waterfloods and caustic-polymer waterfloods when compared to commercial partially hydrolyzed polyacrylamides. This new polymer is available in a liquid form (latex) and does not contain any hydrocarbon vehicle, such as those present in inverse- emulsion polyacrylamides.
The question of cost-effectiveness will not be addressed in this paper since it involves so many parameters that are beyond the scope of this technical evaluation.
Not all of the polymers evaluated were compared in each of the various test programs, but every effort was made to compare polymer types generically, i.e., polyacrylamides and a polysaccharide to rule out any glaring differences which might be inherent in their physical form, liquid or dry, molecular weight, or method of preparation. The only polysaccharide investigated was a dry powder product.
Fracturing Water-Sensitive Tuffaceous Reservoirs
Authors: Yang Y. , Han H. X. , Dusseault M. B. , Xu B. C. , Wang X. J. , Yu Y. 
Published: December 2007

Abstract
We present successful hydraulic fracture treatment practices in water sensitive tuffaceous reservoirs in Hailar Basin, China. The reservoirs are of too low permeability to be placed onto production without massive hydraulic fracture treatments. The article describes the geological engineering framework, mineralogy investigation, hydrolytic weakening experiments, as well as application and results of new kinds of fracturing fluids.
Rock mineralogy investigations indicated that rocks in the reservoir have a strong water sensitive property and a strong component of plastic behavior. Some tuffaceous rocks are rich in alkali minerals and become soft when exposed to aqueous fracture fluids. Although the fracture opening mechanism is the same as for normal sandstone, fracture extension is relatively suppressed and the fracture width is different from elastic predictions for normal sandstone.
The analysis led to the changes in treatment stratages. The key difference from previous treatment is that clay content and concentration of different minerals were taken into consideration of fracture fluid design. Different kinds of emulsified fracturing fluid were designed used to mitigate swelling and hydrolytic weakening effects. By the end of 2005, 163 intervals in 66 wells have been treated using these new kinds of fracturing fluids, with a success rate of 97%.
High-Temperature Drilling Fluid for Geothermal and Deep Sensitive Formations
Authors: Hilscher Larry W. , Clements William R. 
Published: December 2007

ABSTRACT
A new high temperature drilling fluid system has been developed. The system which uses a thermally stable deflocculant and fluid loss additive has been tested in the laboratory at temperatures up to 450°F (232°C). It provides stable rheological properties and good filtration control even in the presence of severe cement contamination. Lime may be used with the system to inhibit shale swelling and dispersion.
Crossplot Technique for the Analysis of the Carbon/Oxygen Log
Authors: O'Brien William Jay , Brown Susan L. , Sanyal Subir K. 
Published: December 2007

ABSTRACT
A graphical technique is presented to compute hydrocarbon saturation from induced gamma ray spectroscopy (IGS) logs. The technique is based on a linear equation that approximates the carbon-oxygen-ratio log response as a function of porosity, shale volume fraction, and hydrocarbon saturation. Coefficients of the equation are obtained from empirical crossplots. Porosity and shale volume fraction are computed from open hole logs.
IGS logs are often run in cased hole wells to monitor hydrocarbon saturation in low salinity reservoirs for enhanced oil recovery (EOR) projects. Two examples are given from an EOR project of the North Kern Front Field in Bakersfield, California. The examples illustrate the crossplot approach for a shaly-sand, heavy-oil reservoir under steam drive. Hydrocarbon saturations obtained using this technique are compared with core and Dresser Atlas' computed data. The results compare favorably with core data.
A Competent and Practical Approach to Well Testing and Analysis in Tight Gas Resevoirs
Authors: Branagan Paul , Cotner Gene 
Published: December 2007

ABSTRACT
Well testing of low permeability gas formations generally concerns itself with acquiring quantitative information of a number of reservoir parameters including: initial reservoir pressurereservoir permeabilityskin effects or damagereservoir boundariespropped fracture lengthfracture conductivitydeliverability
These and other parameters are obtained from essentially the following three distinct types of pressure transient well tests: drill stem testspre-frac testspost-frac tests
These well tests involve both drawdown and buildup periods and the subsequent analysis is generally based on measured or derived bottomhole pressure data and surface flow rates. A great deal of literature has been written describing gas well testing and the various analytic techniques1–5. Although the basic assumptions and limitations for each type of technique are described, the fact is that most of these assumptions or limitations are difficult, if not impossible, to adhere to, particularly in a field environment. Numerous authors6–8 have fixed upon certain of these fundamental assumptions and proceeded to suggest alternative methods or variations in the analytic technique that would tend to compensate for the discrepancies and thus decrease the induced error.
Fracture Porosimeter — A New Tool for Determining Fracture Conductivity under Downhole Stress
Authors: Wendorff C. L. 
Published: December 2007

ABSTRACT
This paper describes a new, fast, simplified procedure for determining fracture conductivity at downhole stresses. The embedment and crushing of proppant between rock samples from a specific formation are measured at closure stresses. The conductivities of fractures propped with various proppants can be determined rather quickly. As a result, the procedure can supply information useful in determining optimum fracture treatment for a specific well.
In the new procedure, samples of formation and proppants are placed in an appropriate confinement chamber. Closure stresses are applied and fracture conductivity can be calculated.
A proppant data base obtained using a modified Cooke2 conductivity test unit includes permeabilities, porosities and fracture widths measured over a range of closure stresses. These properties are dependent upon the type and amount of proppant tested and the stress applied.
Fracture porosity determinations can be made in a short time with a relatively small investment in equipment. Core preparation and testing time require a few manhours per test.
The paper includes examples of permeability and surface areas of conventional proppants. Fracture conductivity determinations, made with a variety of formations and proppants, indicate how this procedure can be useful when making decisions concerning fracture treatment design.
An improvement in equipment design is also presented. The use of a Hoek11 triaxial cell as a fracture porosimeter allows the application of both closure and confining stresses, thus more closely simulating downhole conditions.
Dispersion in Flow through Porous Media
Authors: Sahimi Muhammad , Heiba Adel A. , Hughes Barry D. , Davis H. Ted , Scriven L. E. 
Published: December 2007

ABSTRACT
Dispersion is a consequence of flow. It results from the different paths and speeds and the consequent range of transit times available to tracer particles convected across a permeable medium. The kinematic mechanism stems from the connectivity structure of porespace; the dynamic mechanism, from the effect of pore shape and size on flow. Molecular diffusion can modify both. In many circumstances these mechanisms lead to distributions of macroscopic average solute or tracer concentration that are diffusive, i.e. that can be modeled by the convective diffusion equation, dispersion coefficients taking the role of diffusivity.
For cases of diffusive mixing locally at pore junctions and no appreciable diffusion between, a simple network approximation is appropriate. Square and simple cubic networks of variable pore segments, with average flow in one of the pore directions, are useful idealizations. Dispersion in one– and two–phase flow through these networks is studied here by the Monte Carlo strategy of replicated computer experiments. This strategy combined, with considerable computational savings, with the percolation theory of fluid distributions in two-phase flow. Network topology and pore geometry and thus the two basic mechanisms are precisely controlled.
The results show that dispersion is diffusive in the cases simulated. Longitudinal (mean flow direction) dispersivity is an order of magnitude greater than dispersivity in transverse directions. In two-phase flow, longitudinal dispersivity in a given phase rises greatly as the saturation of that phase approaches residual, i.e. its percolation threshold; transverse dispersivity also increases, but more slowly. As the threshold is neared, the backbone of the subnetwork occupied by the phase becomes increasingly tortuous, with local mazes spotted along it that are highly effective dispersers.
All of the findings accord qualitatively with most available data, except that dispersivities in reality are not constant but increase slowly with macroscopic average flow rate, which may stem from molecular diffusion that is lost from the network approximation used.
Interpretation of Mixed Wettability States in Reservoir Rocks
Authors: Melrose J. C. 
Published: December 2007

ABSTRACT
It has recently been noted that the diffuse electrical double layers which exist at (1) the oil/ brine and (2) the mineral/brine interfaces in sandstone reservoirs will in many cases be quite similar with respect to electric charge and potential. Extremely thin aqueous wetting films separating such interfaces are thus stabilized by the electrostatic repulsive force acting between the double layers. In the present paper the limits under which stable thin films can exist are examined in more detail. It is shown that there exists a lower limit to the pore size in which thin wetting films will occur and that this limiting size depends on the salinity of the brine. It is also shown that whether this limiting pore size becomes a factor in determining the wettability of the rock/brine/oil system depends on the pore size distribution curve and on the initial brine saturation of the rock. Geological factors which may come into play in establishing the initial water saturation in a given case are discussed.
Flow Mechanism of Forchheimer's Cubic Equation in High-Velocity Radial Gas Flow Through Porous Media
Authors: Ezeudembah Agodi S. , Dranchuk P. M. 
Published: December 2007

ABSTRACT
Until recently, the visco-inertial flow equation, which is an adaptation of Forchheimer's quadratic equation, has been used to describe gas flow behavior at higher flow rates and pressures. The inability of this equation, in some cases, to fully describe high-velocity, high-pressure gas flow behavior, especially around the wellbore, led to the consideration of other empirical equations.
In this paper, formal derivation of Forchheimer's cubic equation is made by considering the kinetic energy equation of mean flow and dimensional relations for one-dimensional, linear, incompressible fluid flow. By the addition of the cubic term, this equation is regarded as a modified Forchheimer's quadratic equation which accounts for the flow rates obtained beyond the laminar flow condition. The cubic equation spans a wide range of flow rates and regimes, i.e. Darcy type, inertial type, and turbulent. For suitable use in gas flow studies, this equation has been adapted, modified, and corrected for the gas slippage effect.
The physical basis of the cubic term has been established by using boundary layer theory to explain the high-velocity, high-pressure flow behavior through a porous path. Gamma, the main parameter in the cubic term, is directly related to a characteristic, dimensionless shape factor which is significant at higher flow rates. It is inversely related to viscosity, but has no dependence on the gas slippage coefficient in the higher flow regime.
Errors in K-Values Prediction and Its Effect on Natural Gas Processings
Authors: Hemeida Adel M. , Desouky Saad Eldeen M. 
Published: December 2007

ABSTRACT
Computer programs vere designed to calculate K-values and enthalpy by using different methods for multi-component system. Results show that, a variation of 9.91 percent in the K-value of methane causes a variation of 31.2 percent of the produced liquid, and a deviation in the range of 1.15% of the condensed liquid is obtained from Canfield1, M. G. Kesler and B. I. Lee2 equations. Also operating conditions can be determined from material and heat balance calculations by using modified Redlich-Kwong MRK3,4 equation with an average error of -2.683%
Response of the Deep Propagation Tool in Invaded Boreholes
Authors: Chew W. C. 
Published: December 2007

ABSTRACT
The problem of the radiation of a current loop antenna in a multicylindrical medium is formulated exactly in terms of an integral and an iterative scheme making the integral more tenable to approximation. This closely approximates the response of the Deep Propagation Tool (DPT* tool) in invaded boreholes. To enhance the understanding of the wave due to the current loop antenna, the integral is approximated in the limit in which the antenna spacing is much greater than the diameter of invasion, or the frequency is low. The approximation shows that the wave, for the case of shallow invasion, resembles the response of a loop antenna in an unbounded medium. An iterative scheme is devised to systematically compute the approximation for an arbitrary number of cylindrical layers. The approximation to the response allows one to understand easily the present operating principle of the Deep Propagation Tool and provides better physical insight into the problem.