bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of Emulsions for Mobility Control During Steamflooding
Authors: French T. R. , Broz J. S. , Lorenz P. B. , Bertus K. M. 
Published: December 2007

ABSTRACT
It is widely known that the economics of many steamflood enhanced oil recovery (EOR) projects are strongly affected by steam override (gravity segregation) and steam channeling. The economic performance of many steamfloods can be improved if an effective method of plugging the steam override or channeling zones is utilized. Traditionally, foam blocking techniques have been utilized with variable success to achieve these goals.
In this paper, laboratory results from research at the National Institute for Petroleum and Energy Research on the development of an emulsion blocking technique for the correction and control of steam override and channeling are presented. Coreflood experiments were performed to demonstrate the effectiveness of emulsion blocking at temperatures ranging from ambient to 194°C. The permeability reduction of various types of cores using externally produced emulsions and in situ generated emulsions was measured for light and heavy crude oils. Externally produced emulsions injected into oil-free cores reduced the permeability by 86 percent at 110° and 77 percent at 160°C. Injection of externally produced emulsions into cores containing residual oil, where some of the pores are already blocked, resulted in 30 to 91 percent reduction in permeability. Emulsions generated in situ using caustic to emulsify Wilmington crude oil achieved a 43 percent reduction in effective permeability with the absolute permeability of this core being 1,400 md. In both cases of injected and in situ emulsions, the emulsion block was thermally stable, and no degradation of the block was observed after injection of many pore volumes of water.
The strong possibility that foamblocks as heretofore applied may have an emulsion blocking component to the overall plugging mechanism is discussed. Foams created with known foaming agents were contacted with various crude oils, and emulsified droplets within the liquid interfaces were observed.
Work leading to the development of a field pilot test and ultimate commercialization of the process is presented. Laboratory studies for a planned field pilot were performed using sandpacks made from Kern River unconsolidated core and emulsion produced from the oil and water available in that field.
A Semianalytical Model for Hot Water Surfactant Flooding in a Linear Reservoir with Heat Losses
Authors: K’Vella D. E. , Dehghani K. , Ostermann R. D. 
Published: December 2007

ABSTRACT
This study presents a semi-analytical model of combined injection of hot water and chemical in a linear homogeneous medium. The model takes into account lateral heat losses and horizontal heat conduction for two phase flow with surfactant travelling in the water phase only. Using the correlations available in the literature, the model considers the dependence of the chemical adsorption on temperature, and the relative permeabilities variation with temperature and interfacial tension. The physical dispersion of the chemical and the change of heat capacities and densities with temperature were assumed to be negligible.
The reduction in interfacial tension between aqueous and oelic phase, combined with an Increased mobility achieved at high temperatures was shown to enhance the recovery efficiency of a standard hot water flooding process. The sensitivity of the recovery process with different cases of heat transfer was investigated. The results show that neglecting lateral heat losses and horizontal conduction overestimates the recovery, while neglecting horizontal conduction leads to an underestimation of the oil recovery.
Relative Permeability from Centrifuge Data
Authors: Firoozabadi A. , Aziz K. 
Published: December 2007

ABSTRACT
The drainage of a wetting phase (say oil) by a non-wetting phase (say gas) may be simulated in the centrifuge by two liquids. Such experiments were conducted on a number of cores and they are discussed in a companion paper. In this paper we consider two of the cores with available capillary pressure data. Two forms of the relative permeability models are selected and the parameters of these models are obtained by history matching with a numerical simulator developed for this study that properly accounts for the capillary pressure and the boundary conditions in centrifuge experiments. It is shown that; (1) recoveries can be matched with two – and maybe even more – very different sets of relative permeability curves; (2) recoveries are sensitive to the parameters of each relative permeability model; (3) excellent history match is possible with arbitrarily small capillary pressure values, but the resulting relative permeabilities are different from those obtained with experimental values of the capillary pressure; and (4) late time predictions can be improved by using a linear relationship for the wetting phase relative permeability below some arbitrary value of the wetting phase saturation.
It is concluded that the capillary pressure (Pc) term should not be ignored in obtaining relative permeability curves from centrifuge data. Analytical or numerical models that do not properly include Pc or ignore Pc should be used with caution.
Delayed Crosslinked Gels: Their Role in Aqueous Foam Fracturing
Authors: Freeman E. R. , Bilden D. M. , Hossaini M. 
Published: December 2007

ABSTRACT
Foam fracturing with a base fluid of delayed crosslinked gel has expanded the use of foams in fracture stimulation and greatly improved job success rates. Foamed delayed crosslinked gels allow the placement of much higher proppant concentrations in the fracture than foamed linear gels. Also, the fracture fluid efficiency is greatly enhanced allowing better control of downhole fracturing parameters (e.g. leakoff) critical for successful stimulation.
Laboratory results indicate that the foaming of a delayed crosslinking gel increases apparent viscosity, improves proppant transport capabilities, and extends fluid loss properties beyond those of foamed linear gels.
More than 200 treatments have been completed in various formations in California, Texas, and Oklahoma. A review of local formation characteristics and treatment conditions are discussed regarding the application and successful use of a crosslinked versus conventional linear gel foam.
Noteworthy is that crosslinking the gelled phase of a foam system requires limited modification of current foam fracturing procedures or equipment.
Some Parameters Influencing the Formation and Propagation of Foams in Porous Media
Authors: Friedmann F. , Jensen J. A. 
Published: December 2007

ABSTRACT
Experiments were run to investigate the effect of surfactant concentration, injection rate, foam quality, oil saturation, and rock absolute permeability on the formation and propagation of foams in Berea sandstones and Ottawa sandpacks.
First, constant pressure unsteady-state gas-liquid relative permeability experiments were conducted in Berea sandstone for varying residual saturations of synthetic oil. It was found that high oil saturations can hinder the formation of foam (no substantial decrease in the gas phase relative permeability). In such cases, some of the oil must first be displaced from the core before a foam can form.
Other experiments were performed by flowing preformed foams into cores at various conditions. The foams were preformed at high rates representative of tubing or sandface rates. They were injected into the porous medium at lower rates representative of near wellbore conditions (1.5-5 m from the wellbore) but not of in-depth reservoir conditions. Results showed that the foam propagation rate was significantly affected by rock permeability and injected foam texture. In high permeability sandpacks (40-50 darcies), the foam propagated at the same rate as the liquid phase. Foam propagation rates decreased substantially in lower permeability media.
Susceptibility of Petroleum Reservoir Sands to Water Damage, Powder River Basin, Wyoming
Authors: White E.J. , Baptist O.C. , Land C.S. 
Published: December 2007

Abstract
The productivity of some oil sands may be reduced if invaded by fresh water during drilling, completion or workover operations. The most common cause of formation damage is swelling clay minerals in the sand. Damage is also caused by movement of loose particles or increased water saturation.
The susceptibility of water damage of the producing sands in the basin was estimated by using several laboratory tests. The results of the different tests generally indicated about the same degree of sensitivity, suggesting that sensitivity can be determined by using only one or two tests. However, the other tests are also useful because each illuminates a different aspect of capillary behavior.
Zones exhibiting a high degree of sensitivity in wells were usually found to be interbedded with zones having moderate to low sensitivity. Also, the average sensitivity of the more sensitive sands varied significantly from field to field, making it desirable to determine the sensitivity of questionable sands in each field early in the development program.
Of the 10 sands studied, four exhibited either high or moderate sensitivity; of these four, three are of Upper Cretaceous age, and the other one is Jurassic. Except for the Jurassic, all sands older than Upper Cretaceous have low sensitivity.

Introduction

Well Completions and Water Damage
The productive capacity of some oil wells is seriously reduced when filtrate from water-base mud invades the formation during the drilling or completion of the well. Sands that are susceptible to this type of damage are sometimes called water sensitive. Any one or more of several factors may be responsible for water damage; these are swelling clays, particle transportation, low-permeability water block and water block in oil-wet sands. Of these, no doubt the most common type of sensitivity is that caused by clay minerals [either by swelling or transportation], and it is this type with which this study is primarily concerned.
All clay minerals undergo some, though differing, amounts of swelling when wetted with water; therefore, if present in sufficient quantity, they may impart some degree of sensitivity to sands.
ES100PC: A Multiphase Flow/Nodal Analysis Program for IBM Personal Computers
Authors: Stoisits R. F. 
Published: December 2007

ABSTRACT
ES100pc is a multi-phase flow pressure drop/systems analysis program designed to run on the IBM XT or AT. It has the capability to perform pressure loss calculations in wellbores, flowlines and pipelines. Inflow performance curve calculations are also available. Pressure loss in flowing or gas lifted wells may be computed. A number of multiphase flow pressure drop correlations are available. The user may select correlations or enter data for the physical properties. Inflow performance curves may be calculated using a variety of correlations.
An input data preprocessor is available to assist the user in building his dataset. This processor allows the user to either create, edit or execute a dataset through a series of prompting messages.
ES100pc is a scaled down version of a mainframe program. Over the past several years the mainframe program has been used by hundreds of engineers within ARCO with good, results. The PC version yields results comparable to the mainframe program while allowing the engineer the autonomy and economy of a micro-computer.
The Use of Microcomputer Spreadsheets to Perform Scoping Analysis for Engineering Applications: Waterflood Candidate Evaluation
Authors: Engler R. A. 
Published: December 2007

ABSTRACT
Much of Reservoir Engineering work involves relatively simple calculations. High powered reservoir simulators and data manipulation routines are important, but not vital in most cases to be able to make a sound economic decision. The use of spreadsheet programs such as LOTUS 1-2-3* enables any engineer to quickly set up and perform many analyses in a very efficient manner, using equations available in any good text on reservoir engineering. The results of a scoping analysis then form the basis for a decision to use more sophisticated analysis methods. Another very significant advantage of using a spreadsheet for this type of work is that output is formatted as the spreadsheet is built. Conventional BASIC or FORTRAN programs require significant additional effort to present results in a suitable format.
An example application illustrating useful techniques would be the analysis of waterflood potential in a field. Examples are shown of spreadsheet templates used for normalizing relative permeability curves, generating fractional flow information, performing log calculations, estimating fluid properties, and calculating waterflood performance using displacement efficiency methods. Once the project is approved, a unitization formula can also be negotiated using the spreadsheet to determine unit working interest based on various parameters and weighting schemes.
This example is intended as a demonstration of the potential uses of a spreadsheet to quickly perform engineering calculations and present the results in a suitable format without elaborate formatting routines. Using techniques such as these allows an economic decision to be made with a minimal engineering investment.
The Use of Public Domain and Inexpensive Software in Education
Authors: Eskijian M. L. 
Published: December 2007

ABSTRACT
Public domain and inexpensive software can be used as a teaching tool in petroleum engineering to enhance the student's capabilities, as well as prepare him for more advanced and sophisticated applications in the workplace. This paper will describe a "toolbox" of applicable software, totalling less than $75, including the disk media. With this "toolbox" the student can become familiar with software for database management, spreadsheet calculations, word processing, graphics and a compiled Pascal language with a built-in editor.
Well Test Engineering Software With Built-In Expert Advice
Authors: Erdle J. C. , Archer D. A. , Stiff T. J. , Callihan M. C. 
Published: December 2007

ABSTRACT
Well Test engineering is a complex function requiring both technical knowledge (facts) and experience (beliefs and heuristics). A large number of computer programs have been developed by E&P companies, service companies, consultants and software vendors to assist engineers and technicians in performing some of the tasks which are considered essential to successful well test engineering problem-solving. The distinguishing feature of a majority of these programs is their emphasis on technical features, rather than overall problem-solving capabilities. In general, as the level of program technical sophistication increases, the problem-solving efficiency of the users decreases, thus presenting a software selection dilemma to users and their managers. One solution to this dilemma is to combine the desired level of technical sophistication with problem-solving assistance in the form of procedures and constraints recommended by "experts" in the theory and application of well test engineering technology. This approach effectively places an "applications" expert over the shoulder of the program user, who is the real expert in the "behavior" of the wells and reservoirs being tested. The solution described in the paper evolves from the emerging science of artificial intelligence and is referred to as "expert systems" technology. The paper describes expert systems technology and its application to a well test engineering software package being developed through the combined efforts of an experienced well test engineer and a computer programming specialist. The concepts introduced enhance the utility of well testing by making expert well test engineering problem-solving capability available to non-expert engineers and technicians.
North Sea Score Card
Authors: Castle G. R. 
Published: December 2007

ABSTRACT
A number of the North Sea oil and gas fields have been developed and produced to a point where it is now possible to compare their historical performance against their original projections. Furthermore, revised forecasts, (which are based on more reliable data) that have been prepared recently for these fields, can also be compared against the original projections. This type of analysis suggests that none of the fields studied for the purpose of this paper merit high scores for good performance. For example: 87% of the fields studied had cost overruns.87% were late in achieving first production.87% have not produced the quantity of oil and gas through the end of 1983 as was originally expected.52% are not expected to achieve the peak levels of production originally forecast.83% have spent more on operating costs through the end of 1983 than was originally expected.
Technique for Considering Fluid Compressibility and Temperature Changes in Mini-Frac Analysis
Authors: Soliman M. Y. 
Published: December 2007

Abstract
An analytical technique has been developed to consider fluid compressibility and temperature changes when making mini-frac analyses.
Mini-frac tests in which the effects of compressibility and changing temperatures are ignored can produce results that are as much as 75% in error. However, techniques for mini-frac analysis presented in current petroleum engineering literature are based on the assumption that fracturing fluid is incompressible and isothermal in nature.
This paper examines the effects that fluid compressibility and temperature changes have on mini-frac analysis by presenting field cases analyzed by the method developed. The analysis was performed using both PK and CZ models as presented in literature.
An example analysis using the PK model showed that when both temperature and compressibility effects are ignored, errors of 300% in calculated fluid loss coefficient and 75% in calculated fracture length are encountered. The same example using CZ models gave 200% and 33% errors in fluid loss coefficient and fracture length, respectively.
Correcting for temperature and compressibility effects is considered through the use of "effective pressure drop," or pressure drop the mini-frac would have exhibited if ideal conditions had prevailed. Developing this concept allows the use of already developed type curves. The approach is analogous to pseudo pressure in well testing. When only compressibility effect is considered, only the magnitude and not the shape of ΔP versus dimensionless time graph is changed. Correcting for both temperature change and compressibility changed both shape and magnitude of the curve. It has been observed that a better match was obtained after such correction.
Fractal Distributions of Reservoir Heterogeneity and their Influence on Fluid Transport
Authors: Hewett T. A. 
Published: December 2007

ABSTRACT
Theories of fluid flow in heterogeneous porous media show that their transport properties are determined by the structure of spatial correlations in the permeability distribution. When the range of these correlations is comparable to or larger than the fluid flow path, solutions of the convective-dispersion equation with an effective dispersivity augmented to account for the dispersive effects of reservoir heterogeneity do not provide accurate predictions of the transport characteristics of the medium. Measurements of property distributions in sedimentary environments show a fractal character with long range correlations. Evaluation of the influence of fractal distributions of permeability on oil recovery process performance requires simulation on a distributed field of properties with a correlation structure matching that in field measurements. The geometric properties and spatial correlation structure of fractal distributions are discussed and methods for measuring the fractal character of field data and synthesizing fields with a similar correlation structure are reviewed.
Development of a Chemical Process for Sand Control
Authors: Burger J. G. , Gadelle C. P. , Marrast J. R. 
Published: December 2007

ABSTRACT
The paper describes the continuous experience gained from the laboratory evaluation and field testing of an original chemical sand consolidation process.
The process involves the successive injections of (a) a polymerizable organic material and proprietary catalysts, and (b) a limited volume of oxygen-containing gas. In some cases, a preflush sequence is recommended beforehand. The binding agent is formed by a chemical reaction between the organic material and oxygen. The existence of a gas flow in the reacting volume contributes to preserve the rock permeability. The laboratory work which led to the optimization of this process is briefly described. Cores are obtained with very good resistance to compression and with essentially unaffected permeability.
The operating procedure and the results of typical field tests are discussed in this paper. Wells were successfully treated in both oil and gas fields. After the treatment, sand-free production has been demonstrated, for durations from several months for the most recent tests, to several years for the older ones. No decrease in productivity index has been observed.
Well Tests in a Complex Sandstone Reservoir
Authors: Towler B. F. 
Published: December 2007

ABSTRACT
The Mereenie field is a large complex sandstone reservoir and the well tests have some pecularities which, though not fully understood, have considerable bearing on the well test interpretation.
The first of these are diurnal pressure variations caused by gravitational effects which particularly affect interference tests. Secondly, because of the high gas-oil ratio, phase segregation in the well bore causes a hump in the Horner plot on some of the build-ups.
Thirdly, in one of the sands in one area of the field there is a marked discrepancy between drawdown and build-up results which is attributed to stress dependent permeability. Also core permeabilities in general do not agree with build-up permeabilities.
Oil and Gas Relative Permeabilities Determined From Rate-Time Performance Data
Authors: Fetkovich M. D. , Guerrero E. T. , Fetkovich M. J. , Thomas L. K. 
Published: December 2007

SUMMARY
This paper presents a method of determining kg/ko, oil relative permeability, kro, and gas relative permeability krg, using oil and gas rate-time performance data from individual wells and from a total field. Advanced decline curve analysis is used to obtain original oil in place, N, and thus saturation; the Δp2 form of an oil inflow performance equation is used to determine kro below the bubble point pressure.
The procedure was used on production data from several wells in a North Sea naturally fractured limestone volatile oil field. Results indicate the calculated oil and gas relative permeabi1ity curves differ from laboratory and correlation calculated curves. By analyzing the oil and gas relative permeability curves of each of the seven wells in the field, it was found that the degree of natural fracturing of a specific well influences the position of the oil and gas relative permeability curves. The results expressed as kg/ko curves appear to be consistent with the field case history findings of Arps for limestone reservoirs – i.e., as the degree of fracturing increases, the kg/ko curves become more unfavorable with respect to oil recovery.
Initial pressure surveys on-each well determine its degree of fracturing while a later field-wide pressure survey confirms the oil-in-place calculated for each well using rate-time decline curve analysis.
Pressure-time data to make these calculations is seldom available for all wells in a field or, when available, is much less frequent than rate-time data. In contrast, the principal calculation methods shown in this paper use rate-time data, thus taking advantage of the most frequently collected and the most widely available information.