bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of Brine Composition on Carbonate Wettability: A Sensitivity Study
Authors: AlShaikh Murtdha , Mahadevan Jagannathan 
Published: June 2014

Abstract
Brine composition has a significant demonstrated impact on the recovery of oil in laboratory corefloods. While low-salinity waterflood in clastics has been studied extensively the impact of brine composition on the recovery in carbonates is relatively less understood and studies are more recent. Wettability measurements using contact angles can reflect the surface energy changes due to adsorption of natural surfactants present in crude oil and the electrostatic, structural components due to the formation of double layer.
In this study we measure the impact of ion composition on the contact angles and interfacial tensions between crude-oil, brine and restored/aged calcite mineral surface using a drop profile analysis method. A 9-factor experimental design is used to quantify the impact of six salts and three interactions. This experimental method design (following the Taguchi method) has the objective to identify the combination of different salts that leads to the lowest oil-wetness and highest water-wetness as measured through the contact angles. The salts used in this study are MgSO4, CaSO4, Na2SO4, NaCl, CaCl2 and MgCl2. The interaction parameters studied are between sodium chloride and sodium sulphate, sodium chloride and calcium chloride, sodium chloride and magnesium chloride respectively.
Based on the outcomes of the analysis of variance (ANOVA) of the results we conclude that the chlorides have the maximum impact on the contact angle change to water-wetness (22% and 31 % respectively for sodium and calcium salts). Reduction in chlorides has the obvious benefit of changing the contact angle to more water-wet and this is a fairly well established result also. The interaction between chloride and sulphates and the interaction between sodium and magnesium ions was found to be significant.
The above results indicate that a combination of salts such as high sulphates with lower cation concentration, can lead to more water-wet conditions. This combination is found to be optimal brine chemistry that leads to the lowest contact angle or the most water-wet condition. It is interesting to note that the lowest contact angle of ~29 degrees (highly water-wet) was obtained with a relatively high total dissolved solid content of 157,000 ppm. This observation is in line with some of the recent studies reported in the literature on carbonate rock corefloods and offers a fundamental explanation.
Schmidt-Wenzel and Peng-Robinson Equations of State for CO2/Hydrocarbon Mixtures: Binary Interaction Parameters and Volume Translation Factors
Authors: Deo Milind D. , Nutakki Ram , Orr Franklin M. 
Published: June 2014

SUMMARY
In this work, optimum binary interaction parameters for a number of paraffinic, naphthenic and aromatic hydrocarbon compounds and CO2 for the Peng-Robinson and the Schmidt-Wenzel equations of state have been determined and trends with respect to temperature, and molecular size and type have been examined. The capability of the two equations of state for liquid density predictions has been assessed and a volume translation approach to improve density predictions has been evaluated.
Field-Wide Variations in Residual Oil Saturation in a North Sea Sandstone Reservoir
Authors: Davies G. W. , Gamble I. J. A. , Heaviside John 
Published: June 2014

Summary
An extensive set of core waterflood data is analyzed to provide a reservoir-wide description of residual oil saturation, Sor. Such core tests are influenced by many parameters, including rock structure, wettability, fluid properties, and experimental procedures. With a data set as large as that used here (more than 200 waterfloods) the effects of these factors can be separated. We investigated rock structure, permeability, porosity, initial water saturation, Swi, and wettability. The data indicated that variations in Sor were caused by trends in Swi and wettability, both of which varied with depth across the transition zone. This implies that a unique Soi/Sor relationship for this reservoir does not exist. The work presented here was used to rescale relative permeability data in regions of the field where spatial variation in Swi exists. The value of the large database for defining trends in reservoir behavior was significant and enabled more accurate reservoir simulation.
Acrylamide-Polymer/Chromium(III)-Carboxylate Gels for Near Wellbore Matrix Treatments
Authors: Sydansk Robert D. 
Published: June 2014

SUMMARY
Acrylamide-polymer/chromium(III)-carboxylate gels have been developed for application to matrix reservoirs as near-wellbore total-shutoff treatments. Laboratory development, testing, and characterization of the new chromium(III) (CrIII) aqueous gels are reported. Results of this study indicate that these gels can be applied to elevated-temperature (up to 260°F) and high-salinity reservoirs. The single-fluid gels are produced by crosslinking low-molecular-weight Polyacrylamide with a CrIII-carboxylate-complex crosslinking agent. Use of low-hydrolysis Polyacrylamide facilitates the application to high-temperature reservoirs.
Imbibition of Surfactant Solutions
Authors: Keijzer P. P. M. , de Vries A. S. 
Published: June 2014

ABSTRACT
The goal of dilute surfactant flooding is to reduce the interfacial tension of the oil/water system to very low values in order to release the residual oil. The question then arises whether oil that would normally be produced by imbibition is lost as a result of such flooding; since the surfactant decreases or eliminates the capillary forces that underlie imbibition.
To study the imbibition behaviour of surfactant solutions, we first focussed on miscible-fluid systems. Both theoretically and experimentally we have shown that miscible fluids can indeed be imbibed, depending on the affinity of the different fluids for the solid.
These effects persist as long as equilibrium (complete mixing) has not been attained. A similar behaviour is expected for low-tension immiscible fluid systems.
We present experimental results showing that indeed the (equilibrium) interfacial tension between model oils and surfactant solutions is not the driving force behind imbibition. For the surfactant systems studied, the conclusion is that lowering the interfacial tension has some effect on the imbibition rate but no effect on ultimate recovery.
A General History Matching Algorithm for Three-Phase, Three-Dimensional Petroleum Reservoirs
Authors: Makhlouf Eliana M. , Chen Wen H. , Wasserman Mel L. , Seinfeld John H. 
Published: June 2014

SUMMARY
A numerical algorithm is developed to estimate absolute permeability in multi-phase, multilayered petroleum reservoirs based upon noisy observation data, such as pressure, water cut, gas-oil ratio and rates of liquid and gas production from individual layers. A Chevron Black-Oil code is used as the basic reservoir simulator in conjunction with this history matching algorithm. Since the history matching inverse problem is ill-posed due to its large dimensionality and the insensitivity of the permeability to measured well data, regularisation and spline approximation of the spatially varying absolute permeability are employed to render the problem computationally well behaved. A stabilizing functional with a gradient operator is used to measure the non-smoothness of the parameter estimates in the regularization approach, and the regularization parameter is determined automatically during the computation. The numerical minimization algorithm is based on the partial conjugate gradient method of Nazareth. Numerical examples are considered in two- and three-phase reservoirs with three layers. The effects of the degree of regularization, spline approximation versus zonation, and differing true areal permeability distributions on the performance of the method are considered.
Feasibility of Near-Wellbore Heating by Electromagnetic Irradiation
Authors: Fanchi John R. 
Published: June 2014

ABSTRACT
An algorithm is developed for estimating the temperature increase near a wellbore associated with electromagnetic heating (EMH) processes. The algorithm accounts for heat loss to confining strata. It is useful for generating a temperature profile of an irradiated reservoir. EMH processes are most applicable as well stimulation techniques. They do not heat enough of the reservoir to serve as a general reservoir heating technique.
Diffusion Effects in Gasflooded Light-Oil Fractured Reservoirs
Authors: Morel D. , Bourbiaux B. , Latil M. , Thiébot B. 
Published: June 2014

SUMMARY
The combined effects of gas diffusion and stripping in the matrix blocks of light-oil fractured reservoirs subjected to methane or nitrogen gas flooding are experimentally studied with a specific automated apparatus. 1D and 3D experiments are performed with a methane pentane mixture. In addition to hydrocarbon recovery, local saturations are measured using a gamma-ray attenuation technique.
Most of the pentane in place is recovered within several weeks. Two main differences appear between methane and nitrogen diffu- sion tests: (a) pentane recovery is about twice as fast with methane as with nitrogen, and (b) saturation profiles reveal a strong capillary end effect for nitrogen injection with an accumulation of liquid near the fissure (1D).
Compositional simulations, including diffusion and capillary phenomena, show that diffusion and Darcy flow take part in the recovery process.
A New Concept of TLP With Gravity-Type Template
Authors: Kobayashi H. , Iida Y. , Mori N. , Kawanishi T. , Hirakawa S. 
Published: June 2014

SUMMARY
A new concept of TLP (Tension Leg Platform) with gravity-type template which allows slide to an ultimate earthquake load is verified to be reasonable and practical by means of analyses and laboratory experiments.
The TLP is applicable for the water depth equal to or more than 500m and the seabed, fairly flat with a certain bearing capacity. Installation work of the TLP is planned to be performed without divers so that the platform has small cost sensitivity to water depth.
Stimulation Optimization in a Low-Permeability Upper Devonian Sandstone Reservoir: A Case History
Authors: Hopkins Christopher W. , Gatens J. Michael , Caballero James S. , Jankura Bruce E. 
Published: June 2014

SUMMARY
This paper presents the results of a successful stimulation optimization study performed on the Fifth Elk Sand reservoir in the Council Run Field, Centre Co. and Clinton Co., PA. The systematic approach used to optimize stimulation results included pre-fracture well test and production data analysis, fracture treatment design optimization, and post-fracture treatment evaluation. This study led to a substantial improvement in stimulation results and an engineered approach for fracturing future wells.
Development of An Analytical Streamtube Model for Estimating Steam Drive Performance
Authors: Emanuel A. S. 
Published: June 2014

SUMMARY
A streamtube model has been developed for estimating the performance of single pattern or full field steam drive projects. The model is based on the algorithm of Aydellote and Pope1 for steam displacement adapted to fixed streamtubes. The program is useful for EOR screening and has potential for project design sensitivity studies.
Reinfiltration in Fractured Porous Media: Part 2 - Two Dimensional Model
Authors: Firoozabadi Abbas , Ishimoto Koichiro , Dindoruk Birol 
Published: June 2014

SUMMARY
The fractional flow equation in a two-dimensional space with mixed boundary conditions is solved, and the expression for the reinfiltration rate across the faces of a matrix block is derived. The results show that there is a considerable variation in rate of reinfiltration across a vertical face of a matrix block. For a matrix block with an inclined face, the lower portion could drain liquid, but the upper portion could be under reinfiltration. The results also show that reinfiltration could be effective in a small area at the top portion of a matrix block.
Minimization of Grid Orientation Effects Through Use of Higher Order Finite Difference Methods
Authors: Chen W. H. , Durlofsky L. J. , Engquist B. , Osher S. 
Published: June 2014

ABSTRACT
Grid orientation effects can arise in simulations of recovery processes when the mobility ratio of the displacement is unfavorable. These effects result from the application of numerical solution techniques to equations describing physically unstable displacement processes. In theory, the introduction of stabilizing terms (such as physical dispersion in the case of a miscible displacement) in the governing equations acts to minimize these effects. In practice, however, the numerical dispersion resulting from the first order discretization of the convective terms overwhelms the physically dispersive terms, and the stabilizing effects of these terms are not accurately modeled.
In this paper, we apply higher order, shock capturing, finite difference methods to the simulation of miscible and immiscible displacement processes. This will be shown to reduce numerical dispersion to a level where the effects of the stabilizing terms can be accurately resolved numerically, resulting in the minimization of grid orientation effects. Two different families of higher order methods are investigated. The first such method, a so-called second order TVD (total variation diminishing) scheme, reduces numerical dispersion somewhat relative to the usual first order scheme. The second method investigated, a third order ENO (essentially non-oscillatory) scheme, reduces numerical dispersion even further, to an extent such that the stabilizing terms can be accurately resolved. This will be seen to nearly eliminate grid orientation effects in some cases in which the usual first order finite difference approach yields highly grid dependent solutions and the second order approach yields slightly grid dependent solutions.
The Effects of Wettability and Heterogeneities on the Recovery of Waterflood Residual Oil With Low Pressure Inert Gas Injection Assisted by Gravity Drainage
Authors: Catalan Lionel J. J. , Dullien Francis A. L. , Chatzis Ioannis 
Published: June 2014

SUMMARYIt is shown that in the laboratory a very large percentage of low viscosity waterflood residual oil can be recovered with low pressure inert gas injection, assisted by gravity drainage, from both water-wet and oil-wet samples. A semipermeable membrane made with a mixed-wet paste assures the production of both oil and water, but prevents gas production and eliminates capillary end effects. Stacks of short core plugs can be produced equally as a single core if a coarse version of the mixed-wet paste is used between adjacent plugs. In water-wet cores, displacement of waterflood residual oil requires a positive spreading coefficient of oil on water in the presence of gas. Parallel-type macroscopic heterogeneities in the formation may have relatively little effect on the course of oil recovery, but they prevent the establishment of a uniform saturation in the core cross-section. Because the oil is redistributed in smaller pores during gravity drainage, microscopic pore scale heterogeneities decrease the recovery efficiency.
A Methodology for The Economic Evaluation of Exploration Projects
Authors: Rosbaco Juan 
Published: June 2014

ABSTRACT
Notwithstanding the amount of information on this subject, the economic evaluation of oil exploration projects still has two major drawbacks: (a) the common belief that economics are of no value due to the uncertainties involved, and (b) the fact that the few methodologies that cover all stages of evaluation are not widespread.
This paper presents a simple way of visualizing the exploration business. The methodology, commonly used by company managers, is no more than the formulation of disbursements, potential earnings and probabilities, in terms that are typical of gambling: participation cost, success probability and associated bonus. This very simple perception of the problem plainly demonstrates the need to assign a numerical value not only to the project costs but also to its likely outcome and occurrence probabilities.
Once the need to evaluate is established, a methodology and a work sequence, successfully applied in many different cases, are proposed. How to solve each of the above stages shall be designed considering the nature, quantity and quality of all available data.
The paper presents a discussion of the proposed methodology and a case history.
Application of Geostatistics to Forecast Performance for Waterflooding an Oil Field
Authors: Poquioma W. , Kelkar Mohan 
Published: June 2014

ABSTRACT
This paper presents the results of the investigation on using geostatistical techniques (ordinary kriging and sequential indicator simulation) to generate distributions of porosity, permeability, initial water saturation, layer thickness and top of the structure of an oil field in Venezuela. These distributions were used in Black-oil simulator to evaluate waterflooding performance. Simulated results compared well with production data (shut-in reservoir pressures) without the help of conventional "history match". This comparison indicates that conditional simulation techniques can be effectively used to represent the variability of the reservoir properties.
Ionic Size and the Ability of Electrolytes as Clay Stabilizers
Authors: Huerta M. M. , McQuarrie D. A. 
Published: June 2014

SUMMARY
We have solved the Poisson-Boltzmann equation that explicitly considers ionic size effects of the electrolyte. We have used this model to calculate the net force of interaction between clay particles immersed in electrolytic solution with different counterions. We have found that the least net force of interaction between the clay particles is exhibited when particles are immersed in electrolytic solution with the smallest counterion. By using this model we are able to predict the trend of LiCl, NaCl and KCl in their ability as clay stabilizers in oil reservoirs.
Numerical Simulation Study of Gas Injection in the Lower Lagunillas Reservoir, Block III/IV, Lake Maracaibo
Authors: Todd M. R. , Claridge E. L. , Rodriguez R. A. , Prats M. 
Published: June 2014

ABSTRACTA numerical model has been developed for simulating gas injection processes for enhanced oil recovery in the Lower Lagunillas Block III/IV reservoir. The main elements of this model are 1) a fluid property package which includes phase behavior and transport properties for the inert-gas/solution-gas/oil/water system, and 2) a geological model which includes a detailed description of the reservoir stratification for the three main productive zones.The gas injection processes are seen to be characterized by strong compositional effects. This makes predicted oil recovery results sensitive to the composition of the injected gas. Furthermore, through the well inflow and lift performances, the predicted oil recovery results are found strongly influenced by the field pressure performance. This makes the results sensitive to the production well and field operating policies.Relative to continuing produced-gas injection at 30 MMscf/day, inert-gas (flue-gas) injection at a proposed rate of 90 MMscf/day might increase cumulative oil recovery by over 57 MM STBO. Produced-gas injection at 90 MMscf/day might increase cumulative oil production by another 52 MM STBO over inert-gas injection.
Pseudorelative Permeabilities from Fractal Distributions
Authors: Beier Richard A. 
Published: June 2014

ABSTRACT
Fractal distributions of porosity and permeability in two-dimensional vertical cross sections can be used to represent reservoir heterogeneity. We compare a hybrid finite-difference/streamtube method and pseudo-relative permeabilities as two methods of using these distributions in reservoir simulations. We simulate waterflood displacements in a field case study and some additional sensitivity cases. In all the cases studied, predicted cumulative oil production values agree within 5 percent between the two methods.
Near-Critical Phase Behavior of Reservoir Fluids Using Equations of State
Authors: Arbabi Sepehr , Firoozabadi Abbas 
Published: June 2014

SUMMARY
Phase behavior prediction by an equation of state in the near-critical region shows extreme sensitivity to the binary interaction coefficients. For binary mixtures, these coefficients have a systematic decreasing trend as the critical point is approached. Such a trend can be used to calculate the phase behavior of binary mixtures in the critical region. For complex near-critical reservoir fluids, a variable interaction coefficient may not provide satisfactory results. A fixed reduction of the binary interaction coefficients is a simple practical step towards EOS prediction of phase behavior of complex reservoir fluids.
Demulsifying the Produced Fluids from Marathon's M-1 Micellar/Polymer Project
Authors: Duke R. B. 
Published: June 2014

SUMMARY
Using conventional oilfield processing equipment, such as free-water knockouts, retention tanks, and heater treaters, in conjunction with commercially-available demulsifiers (CADs), the produced-fluid emulsion from Marathon's M-1 micellar/polymer project could not be broken in a cost-effective manner. After evaluating numerous CADs with dismal results, two polyoxypropylene amines (POPAs), found useful in laboratory demulsification studies, were field tested. Neither of the chemicals is manufactured primarily as a demulsifier.
Compared with the CADs, the field tests showed that the POPAs (1) markedly accelerated the separation rates, (2) dramatically improved the quality of the sell oil and disposal brine, (3) lowered chemical consumption and its corresponding cost by over 50 percent, (4) substantially reduced the amount of processing equipment, and (5) significantly decreased the number of operators required to man the treating facility. These findings led to the adoption of the POPAs as the treating chemicals for the M-1 Project.
This paper describes the produced-fluid emulsion from the M-1 Project, details the treating problems encountered while using CADs, and relates how the switch to the POPAs improved both the quality of the separations and the economics of the processing. The time frame for the ensuing discussion is at or near maximum oil production when emulsion problems are most pronounced.
New Procedure for Phase-Equilibrium Computations in Compositional Reservoir Simulators
Authors: Litvak M. L. 
Published: June 2014

SUMMARY
A new procedure for phase–equilibrium computations is proposed. It is applied in a three–phase compositional reservoir simulator for the definition of component distributions in hydrocarbon phases. An effective technique based on the volume balance method is used for the simultaneous solution of phase–equilibrium and reservoir flow material–balance equations.
Compositions of hydrocarbon phases are determined in the proposed procedure by minimizing the Gibbs free energy subject to two inequality constraints. A cubic equation of state is applied for the determination of fugacity coefficients and compressibility factors. Phase–equilibrium K–values or their reciprocals are used as independent variables. An effective minimization procedure is developed. In this procedure, a linear combination of conjugate vectors is selected as a descent direction and the mass conservation equations are exactly satisfied on each iteration.
The new procedure requires, approximately, the same amount of computations as the conventional approaches. However, it converges significantly faster and it is robust even near critical conditions.
This procedure has been implemented in an industrial reservoir simulator. It has been tested for different fluid conditions. The test results demonstrate that the proposed procedure is computationally more efficient and robust than existing techniques.