bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reducing Reservoir Prediction Uncertainty Using Seismic History Matching
Authors: Stephen K. D. , MacBeth C. 
Published: December 2007

Abstract
We have developed a method where the spatial and dynamic information offered by Time-Lapse (4D) seismic has been used in history matching of reservoir simulations. Improved predictions of both recovery and areal sweep are then obtained by reducing uncertainty. Flow simulations are converted to predictions of seismic impedance attributes using a petro-elastic transform and suitable re-scaling. The resulting misfit between the model and observed data is combined with an equivalent measure for well data and these are used to constrain simulations by iteratively updating the model. Updated model probabilities can then be used to analyse uncertainty.
The method has been applied to a UKCS reservoir. Previously we described our success in obtaining a good match to both seismic and production data in the field. From the updated probability distribution of the parameters, we now take the best models from the history matching process and make predictions to determine the most likely outcomes.
We have found that the Time-lapse data reduces uncertainty in predictions of the areal sweep and the pressure distribution. The seismic response is strongest at the injector wells but also helps in the inter-well regions. Conventional history matching often struggles to constrain parameters in these regions due to the inherent non-uniqueness of the problem. The uncertainty of permeability and fault transmissibility multipliers was also determined in those areas.
Simulation of Tectonic Deformation and Large-Area Casing Shear Mechanisms—Part A: Operations
Authors: Han H. , Dusseault M. B. , Xu B. , Peng B. 
Published: December 2007

Abstract
We present an analysis of casing deformation mechanisms in one area of extensive casing shear in the Daqing Oilfield, China. Instead of qualitatively stating the cause of large areas of casing shear, as in most previous work, we developed a mathematical model to quantitatively compute the coupled effect between the tectonic stress field and the induced stresses from high-pressure water injection.
Numerical simulation carried out in the area indicated that variation of injection pressure induced a substantial perturbation on the local stress field. Furthermore, the induced stress fields associated with each injection well overlap with each other. Once the maximum compressive stress parallels or nearly parallels the differential pressure, the stability of strata with respect to shear is compromised, and when the thrust stress imposed exceeds the shearing resistance, the strata will slip in a direction coaxial with the vector from high to low-pressure areas. Simulation results of various schemes show that as long as the injection pressure and pressure differential between blocks are controlled to be less than 12.7 MPa and 0.86 MPa respectively, formation shear slip along a horizontal surface will no longer occur.
The study in this article is somewhat different from previous studies in that a full coupling of the in situ and the induced stress fields was performed quantitatively and based on field experiments, and also in that the results were used to explicitly determine pressure limits on individual wells and differential pressures for the entire region of casing shear. The method and the results can serve as reference for other similar oilfield circumstances.
A Method for Designing A Complex Directional Drilling Program Applied in Cook Inlet, Alaska
Authors: McKayf Thomas Wilson 
Published: December 2007

ABSTRACT
This paper describes a method for designing a complex directional drilling program which was applied offshore in the Cook Inlet of Alaska. Utilizing modern computer and directional drilling technology, Amoco Production Company was able to drill a very complex directional well successfully. Because of this, other wells in the Cook Inlet are also being designed and drilled by Amoco in the same manner.
A Theoretical Model For Determination of Pore Volume Compressibilities of Consolidated Sandstones
Authors: Greenwald Roy F. , Somerton Wilbur H. 
Published: December 2007

ABSTRACT
In another paper (Greenwald and Somerton (1981)) the authors have described experiments which were conducted to determine pore volume compressibilities of Bandera, Berea, and Boise sandstones. The pore volume compressibility is defined as the incremental change in pore volume of a rock with respect to a change in the pore or internal fluid pressure. This work presents a model which allows the pore volume compressibilities of the aforementioned sandstones, and their changes with stress, to be calculated when certain of the samples' physical parameters are specified. The model is semi-empirical in that some of these parameters must be determined experimentally; this is done by actually measuring one or two values of the rock's compressibility. Alternatively, one can make reasonable assumptions for these values when the lithology of the sample is known. Variables required for the implementation of the computational scheme are initial porosity, clay content, a pore shape factor, a length and aspect ratio of representative cracks in the matrix grains, the volumetric density of these cracks, and the mineralogical composition of the sample along with the elastic moduli fo the minerals present. When these data are supplied, the pore volume compressibility can be estimated as a function of any specified stress state of the rock.
A Model of Oil Ganglion Movement in Porous Media
Authors: Egbogah Emmanuel O. , Wright Robert J. , Dawe Richard A. 
Published: December 2007

ABSTRACT
This paper presents a simple theory of the movement of a discontinuous oil droplet (ganglion) through a model porous medium. A quantitative description of the ganglion flow in the system was obtained through a tractable solution to the balance of forces controlling ganglion stability during flow of two immiscible fluids within a well-defined geometry. Calculations were based on a constricted conical (divergent-convergent) pore model. Experimental data from a tetragonally packed sphere model were used interactively with a theoretical static analysis to synthesize the relevant features of the ganglion mechanics into a coherent theory of oil mobilization.
A Method to Determine K-Values From Laboratory Data and Its Applications
Authors: Bashbush Jose L. 
Published: December 2007

ABSTRACT
Retrograde condensate reservoirs and volatile oil reservoirs are not amenable to be studied using traditional material balance methods and simulation techniques. To analize these "variable composition reservoirs", it is necessary to obtain a consistent and reliable set of K-values which might be capable of reproducing the phase behavior of the fluids within the reservoir.
This paper presents a simple and practical material balance method by which liquid compositions, K-values and molecular weights of the heavy fraction in the liquid at different pressures are calculated, based on the data available in a constant volume depletion lab analysis. Results of the analyses of three PVT studies are discussed along with guidelines to evaluate the goodness of reported experimental data and ways to correct inconsistencies commonly found in the reports.
The corrected K-value table generated with the method can be directly used in a compositional study to predict the reservoir behavior. Another use involves the application of the method as a necessary preamble to the adjustment of the parameters of an equation of state. This practice will avoid the great deal of time spent in unsuccessful attempts to match inconsistent information
The Comparative Effectiveness of Propping Agents in the Red Fork Formation of the Anadarko Basin
Authors: Hickey Joe W. , Brown William E. , Crittenden Stephen J. 
Published: December 2007

ABSTRACT
This paper presents the results of an investigation of the comparative effectiveness of various fracture propping agents and their relationship to production performance based on actual field results of twenty-five wells producing from the same formation at approximately the same depth and similar downhole reservoir conditions. All are located in thirteen fields of the Anadarko Basin in Roger Mills and Beckham Counties, Oklahoma (Fig. 1). Every Red Fork well listed in the records of the Oklahoma Corporation Commission for these counties which had been fractured and treated with a propping agent was examined. All wells for which valid production information was available are included. Three of a total of 28 wells were eliminated because of ambiguous data. Fig. 1Location of 25 Red Fork sandstone wells, Beckham & Roger Mills Co., OK
A comparison is made of the actual production of wells measured before and after hydraulic fracture stimulation treatments that employed one or more of the various propping agents; sand, glass beads, resin coated sand, or sintered bauxite. The size and type of treatment varied from well to well.
The relation between actual field results and laboratory tests under simulated field conditions is reviewed for the several types of proppants.
A Useful Technique to Study Particle Invasion in Porous Media by Backscattered Electron Imaging
Authors: Kandarpa Viv , Sparrow John T. 
Published: December 2007

ABSTRACT
The flow mechanism of aqueous fluids containing particles is important for an understanding of the invasion and impairment of petroleum and geothermal formations by particulate matter. This paper describes a relatively new technique that is successfully being used in flow studies of particle suspensions through Berea sandstone cores. The technique is based upon backscattered electron imaging in the scanning electron microscope (SEM). The visual observation by SEM of the particles inside the cores is made possible by using particles made up of elements which are known to have a higher backscattering coefficient than the silicon matrix of the sandstone.
The present paper is part of a major study on Berea sandstone cores in which the effects of fluid flow rate, the particle size, the chemical nature of the particles and the particle concentrations have been studied. The backscattered electron imaging technique has been utilized to determine the distribution and depth of penetration of particles in cores. Other related applications of the technique to determine BaS04 and CaS04 precipitations in cores due to incompatible mixing of waters are also briefly mentioned.
Mechanisms of Formation Damage in Matrix Permeability Geothermal Wells
Authors: Bergosh Gerald L. , Enniss Dan O. 
Published: December 2007

ABSTRACT
A laboratory study was conducted at simulated in-situ geothermal conditions to identify the mechanisms responsible for significant declines in permeability. Testing was conducted on core material retrieved from Well 78-30 in the East Mesa KGRA, Imperial Valley, California. In this paper, apparatus, procedures and results are described. Damage in this formation, which was not originally thought to be water sensitive, is attributed to cation exchange and the removal processes which alter the stability of the clay structures. Fluid shearing dislodges particles, which clog pore throats and irreversibly reduce permeability. The implications of these findings on operating procedures and production of the well can be significant and are discussed.
Petrologic Evaluation of the Silurian Interlake Formation, Vida Field, North-Eastern Montana—The Key to Revitalized Exploration in an Oil Field
Authors: Powell Thomas G. , Stevenson G. M. 
Published: December 2007

ABSTRACT
Potentially productive zones in carbonate reservoirs are often missed because log suites fail to identify the extent and nature of effective porosity. The Silurian Interlake Formation produces at the Vida Field in McCone County, Montana. In 1963, eighty-seven feet of the Silurian Interlake Formation were cored in the Phillips Sievers #1 Well, Sec. 30, T.24N., R.50E., McCone County, Montana. The cored interval was evaluated using core description, thin section petrology, scanning electron microscopy, and log analysis. Data obtained through these methods were integrated to evaluate the nature of the porosity in the Interlake Formation producing from the Sievers #1 Well. As of 1980, its cumulative production was 253,979 barrels of oil and 14,560 barrels of water. Deposition of carbonate mud and bioclastic debris is interpreted to have taken place on a laterally extensive, extremely shallow, slowly subsiding, carbonate shelf. The productive interval is a dolomitized wackestone, packstone, and mudstone. The main porosity types are intercrystalline, moldic, and fracture. This observed porosity is the direct result of diagenetic alterations imposed upon the original sediment. The major diagenetic alteration has been dolomitization. Based on analytical work performed on the Interlake Formation in the Sievers #1 Well, the Staman 2-25 Berreth Well (Sec. 25, T.24N., R.49E.) was drilled and cored in November-December, 1980, to test the possibility that additional reserves remain in the Vida Field. Comparison of the two cored intervals confirms the existence of additional porosity developed in the same lithofacies described in both wells. It is concluded that carbonate log response should be correlated to porosity and lithology to insure maximum exploitation of a reservoir.
The Positive Effects of Side Rake in Oilfield Bits Using Polycrystalline Diamond Compact Cutters
Authors: Huang Hsin I. , Iversen Robert E. 
Published: December 2007

ABSTRACT
What used to be considered a novel drilling technique, the use of synthetic diamond cutters in a drag bit configuration, has now emerged in the drilling industry as a time and cost efficient drilling tool. These bits, utilizing polycrystalline diamond compact cutters for drilling soft or plastic formations have been proven successful through a systematic development. First, the main problem associated with drilling soft or plastic formations was identified as bit cleaning. Second, laboratory tests of a single compact cutting plastic shale under confining pressure with a load dynamometer and high speed photography were studied. The results demonstrated that a compact incorporating side rake angle and ample chip clearance space can provide efficient mechanical cleaning action. Finally, new style drill and core bits, built with side rake orientation along with previous style drill and core bits without side rake features, were field tested and observed in the same drill hole or in the same formation. The drill or core bits with side rake features always drilled or cored faster in the soft or plastic formations than those bits without side rake under the same operating parameters (hydraulic, bit weight and rpm). It was concluded that bits with side rake features can enhance the bit cleaning by mechanical cleaning action and, therefore, improve the bit performance in soft or plastic formations.
The Effect of Temperature on Drainage Capillary Pressure in Rocks Using a Modified Centrifuge
Authors: Samaroo Brian Henry , Guerrero E. T. 
Published: December 2007

ABSTRACT
A commercially available centrifuge was modified to measure drainage capillary pressures of various core samples at temperatures up to 400°F. The modifications provided good control over the following core parameters that needed to be accurately measured: maximum capillary pressure, average wetting phase saturation, and temperature. Measurements were made on twelve core samples of various lithologies, with 5% sodium chloride brine as the wetting phase fluid and either nitrogen or McKittrick crude oil as the non-wetting phase fluid, in the following increasing temperature sequence: 105°F, 200°F, 300°F, and 400°F. The lithologies investigated were as follows: clean sandstones, shaly sandstones, and limestone.
The results of this study showed that for the McKittrick crude oil-brine system, the irreducible brine saturation increased with increase in temperature for all lithologies confirming the results of previous investigators. However, for the nitrogen-brine system, irreducible brine saturation was found to decrease with increase in temperature for all lithologies.
The interplay of the effects of capillary and viscous forces as temperature increases is given as a possible explanation for the observed phenomena. Also the implications of these results as applied to formation evaluation and reservoir engineering are discussed.
Simulation of Relative Permeability Hysteresis to the Nonwetting Phase
Authors: Carlson Francis M. 
Published: December 2007

ABSTRACT
In reservoir fluid flow, the situation described by an increase in nonwetting phase saturation followed by an increase in wetting phase saturation causes a relative permeability hysteresis effect that is well known. The imbibition relative permeability is a function of the historical maximum nonwetting phase saturation, hence there is no single imbibition curve applicable for use in reservoir modeling. This paper presents a method which allows the calculation of imbibition relative permeability starting at any saturation. The data required are the drainage curve, the historical maximum nonwetting phase saturation, and a minimum of one additional point on some corresponding experimental imbibition curve. In this development, all imbibition curves are shown to be parallel. Also significant is the fact that the residual nonwetting phase saturation can be calculated without a complete experimental specification of the imbibition curve.
Review Of Secondary Recovery Operations In The Greater Aneth Area, San Juan County, Utah
Authors: Burchell Paul W. , Coonts Harvey L. 
Published: December 2007

Abstract
Secondary recovery operations presently being conducted in the Greater Aneth Area, San Juan County, Utah, are reviewed. Early in the development of the reservoir it became apparent that initial primary recovery would be a small percentage of the total oil in place. It was concluded by the operators that waterflooding would be the most satisfactory method of secondary recovery. Although it is too early in the life of the flood to substantiate, present estimates indicate that the ultimate recovery of oil will probably be twice the recovery anticipated from the original solution gas drive mechanism. Primary recovery has almost been completed and future production will be the result of waterflooding. In addition to the increase of oil recovery, over-all economics will be enhanced by the 80-acre well spacing now in effect.
Introduction
In April 1956, Texaco, Inc. completed the Navajo "D-1" which was the discovery well in what was to become one of the largest fields in the Rocky Mountain Area, the Aneth Field. During the next four years over 600 wells were drilled which delineated a productive area in excess of 55,000 acres with an estimated reserve around one billion barrels of stock tank oil in place. Primary recovery was calculated to be approximately 14.3 to 18.5 percent, and secondary recovery resulting from waterflooding was estimated to increase the initial recovery an additional 12 to 14 percent. It is the purpose of this report to review both the background considerations relating to secondary recovery and its' progress to date.
GEOLOGY
The Aneth Field, later called the Greater Aneth Area, is located in the Utah portion of the Four Corners Area, see Fig. 1. Geologically the field is located on the Southwestern flank of the Paradox basin. The basin covers parts of Utah, Arizona, Colorado and New MEXICO.
Production is from carbonates at a depth between 5,300 ft. to 6,200 ft. in the Paradox Formation which is middle Pennsylvanian in age, specifically, the Desert Creek and Ismay zones of the Paradox. The Desert Creek zone is better developed and more continuous over the area and contributes around 90 percent of the hydrocarbons. This zone is further divided into three subzones of which only the upper two are significant.
The field can be described as a reef complex with structure playing a minor role in accumulation. Reservoir development and porosity are due to fossiliferous deposition with some mineral solution activity and a highly varying fracture system. The productive area is surrounded by shales and reworked, non-porous, clastic carbonates in a somewhat circular area about 10 miles in diameter.
RESERVOIR CHARACTERISTICS
The primary producing mechanism for the reservoir is solution gas expansion. Original bottom hole pressure was 2200 psi at 900 ft. subsea. General core and fluid analysis are shown in the following tabulations:
Approximate height of oil column.............250 ft. Average permeability......................... 20 ft.
Minimum Gas Flow Rate for Continuous Liquid Removal in Gas Wells
Authors: Ilobi Meshack Ike , Ikoku Chi U. 
Published: December 2007

ABSTRACT
Several publications on the prediction of minimum gas flow rates for continuous liquid removal in gas wells are indicative of the interest the industry has in this subject. Some of the noteworthy studies are those of Duggan (1961) and Turner, et al, (1969). One limitation of Turner's work is the treatment of entrained liquid drops in the gas core independent of the continuous film region, even though it is acknowledged that interactions between the two regions exist and are continuous in the entrainment process. Other treatments of the subject have been mainly empirical, based on observation in particular gas fields, with no claims to general application.
A large bank of available experimental data by several investigators for upward annular dispersed flow was used to develop correlations for the prediction of entrainment, film thickness and pressure drops by Hughmark (1973). These correlations have been applied, with some modifications to the gas well situation. Duns and Ros pressure drop correlation has been incorporated in this model because of its better accuracy in the annular-mist flow region.
Comparison of results from this model with field results show marked improvement in minimum gas flow rate prediction accuracy that should be beneficial to the industry.
Pressure Behavior in Vertically Fractured Wells Subject to Limited Entry and Bottom Water Drive
Authors: Ichara Mark J. 
Published: December 2007

ABSTRACT
This paper presents an analytical study of the wellbore pressure behavior for a vertically fractured well subject to limited entry and bottom water drive. The well is producing at a constant rate from (1) an infinitely large reservoir and (2) the center of a rectangular drainage region. The upper boundary of the formation is impermeable but the lower boundary is maintained at constant pressure equal to the initial pressure of the reservoir. Two fracture locations (top and center) within the producing interval are considered. Both infinite-conductivity and uniform-flux fractures are examined. Analysis of drawdown and buildup pressure data by conventional semi-logarithmic techniques are conducted to determine the combined effect of limited entry and bottom water drive on well test analysis.
The study indicates that the use of conventional Horner and Miller-Dyes-Hutchinson semilog methods would give inaccurate results. Consequently, the type curves presented in this paper may be used to estimate reservoir and fracture characteristics in oil, gas and geothermal reservoirs.