bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dependence of Residual Nonwetting Liquid on Pore Topology
Authors: Pathak Prabodh , Davis H. Ted , Scriven L. E. 
Published: December 2007

ABSTRACT
Fluid distributions and flow through the pore-space of reservoir rock depend not only on pore sizes and shapes but also local pore connectivity. This can be characterized in terms of the network concept of coordination but is more appropriately described by the topological invariant called genus, which is the basic measure of the multiplicity of paths through the pore network. The larger the genus per unit volume, the larger the number of alternative paths available for fluid connection and flow. Genus is the number of distinct holes in a holey structure such as porous rock.
Model rocks of a series of pore structures were prepared by controlled sintering of model sediments of three different grain shapes and two grain sizes. The morphology of each core was found by serial sectioning and recording all the relevant dimensions and connections. From features on representative two-dimensional sections the statistics of genus and other relevant properties of the three-dimensional structures were calculated by means of mathematical relations known for random structures.
Resxdual saturat ions when oil was displaced by water, and vice versa, were measured in each core before it was sectioned. The experiments were made at low capillary numbers, and by the Penn State method.
The measured residual saturations of nonwetting liquid in model rocks synthesized from grains of the same size but different shapes correlate re-markably well with genus per unit volume. Pore topology, heretofore unstudied, is as crucial as pore geometry in determining residual nonwetting saturations* The higher the genus, the more alternate routes are available for oil drainage, the larger the average number of choke-off and break-off events it takes to isolate blobs of oil, and so the lower the residual saturation.
Interpretation of Interference Tests in Reservoirs With Double Porosity Behavior—Theory and Field Examples
Authors: Deruyck Bruno G. , Bourdet Dominique P. , DaPrat Giovanni , Ramey Henry J. 
Published: December 2007

ABSTRACT
A systematic approach for analyzing interference tests in reservoirs with double porosity behavior is presented; it applies to both naturally fractured reservoirs and multilayered reservoirs with sufficiently high permeability contrast between layers.
Type curves are presented for the pressure response at an observation well, the active well being produced at either constant flow rate or constant pressure.
They are derived from two models with the assumptions of pseudo-steady state or transient interporosity flow regime. The distinctive specific features they exhibit are clearly identified and quantitatively related to the model parameters.
An interpretation method, based on type curve matching, is proposed: after selection of the most appropriate model, and identification of the successive flow regimes, the double porosity behavior of the reservoir is characterized and pertinent parameters are evaluated: flow conductivity kh, interporosity flow parameter λ, and storativity (ϕVct)h segregation throughout the reservoir.
Actual field examples are discussed to illustrate the method.
Clay Models and Acoustic Velocities
Authors: Minear John W. 
Published: December 2007

ABSTRACT
Acoustic velocity, or porosity derived from the velocity, are often corrected for shale or clay effects. These corrections are largely empirical. Two-phase porous media models are applicable to sedimentary formations and provide a new approach to estimating the effects of shale and clay on clean formations. One particular model is used to calculate the effects of laminated and structural shale and dispersed clay on compressional and shear wave slowness. The calculations suggest that laminated and structural shale have about the same effect. Dispersed clay may have negligible effect. Shale and clay increase shear wave slowness more than compressional wave slowness.
Causes and Prevention of Vibration Induced Failures in Submergible Oilwell Pumping Equipment
Authors: Brinner T. R. , Traylor F. T. , Stewart R. E. 
Published: December 2007

ABSTRACT
Vibration phenomena in Electric Submergible Pumping Systems is rarely identified as the cause of premature system failure. This is the result of a number of factors. The first is a lack of sensed and recorded downhole operational parameters pertinent to the mechanical condition of the machine. The second arises from the practice of attempting restart several times before pulling a failed unit; this procedure has the effect of causing additional damage and thus masking any evidence of vibration. Finally, a vibration induced failure can eventually be manifested in other, more common failure modes which are ultimately credited with causing the event. The point is that failure, regardless of cause, cannot be addressed unless the mode of initiation is understood. This paper suggests that vibration initiated failures, while not frequent, are more prevalent than previously believed. It is also suggested that improvements in reliability will be observed when the phenomena is fully understood and addressed from the equipment design, application, and operation viewpoint. This work describes the vibration problem and the conditions which increase its probability of occurrence. It will also suggest measures to avoid the phenomena, and illustrate this with known field case studies that have been confirmed by experimental laboratory work.
The Geology of the Yellowhouse Unit, Hockley County, Texas
Authors: Long Gregory P. 
Published: December 2007

ABSTRACT
A detailed description of the porosity and permeability trends within the Yellowhouse (San Andres) Unit reservoir was prepared for the Amoco Production Company (USA) Producing Department to aid present and future engineering studies. The waterflood pattern in the western half of the Unit is under consideration for conversion to a 44.25 acre, 5-spot pattern from an 88.5 acre, 5-spot pattern. The geologic study examined the San Andres Formation Zones VIII, IX, and X.
Production within the Unit is from Zone IX. Zones VIII and X were found to be nonproductive. Zones VIII and IX are interpreted to be two shallowing-upward carbonate sequences consisting of (1) subtidal wackestones and burrowed mudstones, (2) intertidal mudstones and algal-1aminated mudstones, and (3) supratidal dolomites and anhydrites. Each of these facies exhibits characteristic porosities and permeabilities. Porosity and permeability data, core descriptions and log response from six cored wells were merged to determine pay quality, zonation and lateral and vertical continuity.
A shelfward decrease in permeability forms the trap in Zone IX. As the subtidal wackestones, in which the porosity and permeability are best developed, grade into the shallower intertidal mudstones, a change in pore type from intercrystalline to moldic is observed. This pore-type change reduces permeability and forms the trap. Additional development potential exists west and south of the Yellowhouse Unit. The data suggests that Zone VIII is tight and nonproductive within the Unit. More core and log data is needed to delineate porosity and permeability trends in Zone X.
Temperature Effects on Relative Permeabilities of Oil-Water Systems
Authors: Sufi Arshad H. , Ramey Henry J. , Brigham William E. 
Published: December 2007

ABSTRACT
Relative permeability is perhaps the most important parameter in describing underground flow behavior of immiscible fluids. In recent years, thermal recovery methods have gained in importance. This requires an understanding of temperature effects on flow characteristics of reservoir fluids.
This paper presents an experimental study dealing with temperature effects on relative permeabilities of oil-water systems. Results indicate that the curves are independent of temperature as are the end point saturations. There is a decrease in "practical" residual oil with temperature saturation due to a change in the shape of the fractional flow curve.
Geothermal Reservoir Testing by Piezometric Surface Drawdown/Buildup
Authors: Bodvarsson Gunnar , Zais Elliot J. 
Published: December 2007

ABSTRACT
The monitoring of a piezometric surface drawdown or buildup provides data that can be interpreted in terms of estimates of reservoir porosity and permeability. In the case of heterogeneous/anisotropic reservoirs such estimates will generally deviate from conventional well testing results. The Laugarnes geothermal field in Southwestern Iceland presents an interesting case where results of both types of test procedures can be compared. Processing and interpreting the piezometric surface data, we find that they lead to estimates of the reservoir permeability of 10 to 50 millidarcy that is orders of magnitude lower than results of conventional well interference testing. The porosity of the reservoir is estimated at 3 × 10-3. This is a plausible value for flood basalts of the rift zone type.
Combined Natural Gamma Ray Spectral/Litho-Density Measurements Applied to Complex Lithologies
Authors: Quirein John A. , Gardner John S. , Watson John T. 
Published: December 2007

ABSTRACT
Well log data has long been used to provide litho-logical descriptions of complex formations. Historically, most of the approaches used have been restrictive because they assumed fixed, known, and distinct lithologies for specified zones. The approach described in this paper attempts to alleviate this restriction by estimating the "probability of a model" for the models suggested as most likely by the reservoir geology. Lithological variables are simultaneously estimated from response equations for each model and combined in accordance with the probability of each respective model.
The initial application of this approach has been the estimation of calcite, quartz, and dolomite in the presence of clays, feldspars, anhydrite, or salt. Estimations were made by using natural gamma ray spectra, photoelectric effect, bulk density, and neutron porosity information.
For each model, response equations and parameter selections are obtained from the thorium vs potassium crossplot and the apparent matrix density vs apparent volumetric photoelectric cross section crossplot. The thorium and potassium response equations are used to estimate the volumes of clay and feldspar. The apparent matrix density and volumetric cross section response equations can then be corrected for the presence of clay and feldspar. A test ensures that the clay correction lies within the limits for the assumed lithology model. If it is not within limits, either the estimate of clay volume or the lithology model, or both, are changed.
Results are presented for varying lithologies. For one test well, 6,000 feet were processed in a single pass, without zoning and without adjusting more than one parameter pick. The program recognized sand, limestone, dolomite, clay, feldspar, anhydrite, and salt without analyst intervention.
Economic Considerations in the Acquisition of Oil and Gas Reserves for Oil Income Programs
Authors: Isaacs V. A. , Doubek R. J. 
Published: December 2007

ABSTRACT
Petro-Lewis has designed a financing format for the acquisition of producing properties. Through this format, individuals can acquire an interest in a Limited Partnership that directly owns the producing properties. For this ownership in the Limited Partnership, the investor receives income derived from the cash flow stream of the producing properties, and liquidity through the General Partner's willingness to buy back this interest on an engineered basis.
This paper will outline the structure which has proved successful in acquiring these properties, as well as describe the evaluation techniques employed, with an analysis of the results which have been achieved during the last ten years.
Expected Returns on Investment in the Giddings, Austin Chalk (Gas) Field
Authors: Reeve Richard P. , Peters Ekwere J. 
Published: December 2007

ABSTRACT
An economic evaluation has been performed to determine the expected returns on investment for a drilling program in the Giddings, Austin Chalk Gas Field. Using projected production schedules of selected well types from the encountered reserve distribution, computer based cashflow analyses were performed under six hypothesized future scenarios of varying hydrocarbon pricing, demand, taxation, and inflation. For the six future scenarios studied, the Giddings Gas Field drilling program was found to produce a positive, after tax net present value, using 15% as a discount factor. Furthermore, the returns on investment were higher for an independent than for a major producer. Our results suggest a drilling program initiated in the near future will prove to be an attractive economic venture.
Experimental Investigation of the Steam Drive Process for the Asphalt Ridge Tar Sands Deposit, Utah
Authors: Watts K. G. , Hutchinson H. L. , Johnson L. A. , Barbour R. V. , Thomas K. P. 
Published: December 2007

ABSTRACT
A series of laboratory experiments was conducted at the University of Wyoming to determine the steamflood recovery mechanisms for the Asphalt Ridge Tar Sands deposit located near Vernal, Utah. Steam at various temperatures and qualities, hot water and also nitrogen were injected into an adiabatic tube containing the tar sands, and the recovery curves were measured. From the results of the experiments, it was concluded that the Asphalt Ridge steamflood mechanisms consist of viscosity reduction, solvent extraction-enrichment, liquid displacement, and steam distillation. In addition to determining the steamflood mechanisms, it was also shown that, for the Asphalt Ridge Tar Sands (1) steam injection recovered more oil than did a hot waterflood at the same temperature (2) thick, viscous oil was produced during low quality steam runs, whereas a lighter oil was produced at higher qualities, and (3) intermediate quality steam will recover more of the original oil in place than will either high quality steam or hot water.
An Analysis of Rate-Sensitive Skin in Oil Wells
Authors: Blacker Laura K. 
Published: December 2007

ABSTRACT
This paper documents the results of the perforating program for the first forty wells in the Kuparuk River Field in Alaska. Several different types of perforating guns were used to perforate the wells at varying shot densities. Pressure transient tests were conducted on each well to measure skin damage and flow efficiency. A correlation of average flow efficiency with perforating gun type and shot density is presented. This shows that shot densities above 4 shots/ft result in less skin damage, and wells completed with 12 shots/ft have little or no damage. The effect of perforation penetration is also shown to be a factor in reducing damage, but with all other factors being equal, 12 shots/ft is shown to result in the least amount of damage.
The above results are explained by a detailed analysis of multiple buildup tests at varying rates which were performed on some of the highly damaged wells completed during the early development of the field. These tests indicated skin damage to be rate sensitive with some true formation damage also present. Non-Darcy flow and gas saturation near the wellbore are shown to contribute to the rate-sensitive skin factors. A method of analysis is presented which allows non-Darcy flow skin factors to be calculated when gas saturation is also causing a skin effect. This can be accomplished without fluid property and relative permeability data, which is necessary to calculate saturation effects using standard analysis methods.
The Development of a General Phase Envelope Construction Algorithm for Reservoir Fluid Studies
Authors: Li Yau-Kun , Nghiem Long X. 
Published: December 2007

ABSTRACT
This paper deals with the development of a general algorithm for phase envelope construction. It extends the pressure-temperature diagram construction method of Michelse1 to the generation of phase envelopes on pressure-composition, temperature-composition and composition-composition diagrams. The bubble point and dew point curves are traced in one pass, and an estimate of the critical point is also given. The loci of mixtures having a constant vapor-liquid split (e.g. 25% vapor mole fraction or volume fraction) can also be generated. The algorithm selects internally the primary variables and the points on the diagram to enhance the convergence.
Results are presented for simple mixtures, typical reservoir oil-CO2 mixtures and a gas condensate. Problems associated with a discontinuity in the phase envelope because of a three-phase region are also presented, and it is shown how an analysis of the Gibbs energy surface can help in discarding unrealistic results.
Financial and Engineering Considerations in Petroleum Property Acquisitions
Authors: Chan S. A. 
Published: December 2007

Abstract
One of the popular methods for a new or growing oil company to quickly build up a reserve base has been to acquire properties through an exchange of the purchaser's stock. While there are definite advantages to both the buyer and seller; in regards to tax treatment of the exchange, in market liquidity for the seller, and in conserving cash of the buyer, there are major considerations that the purchaser should consider, especially from the standpoint of synergistic value added to the purchaser with respect to additional reserves, cash flow, and market value of the purchaser's stock. Numerous companies have attempted to roll oil and gas properties into their reserve asset base through exchanges of stock. In some of these cases, the end result of the exchange has left the purchaser with a larger debt burden, and greater unanticipated capital commitments which end up adversely affecting the purchaser's stock price on the open market.1 There are a number of factors that need to be considered before a petroleum company pursues such a course of action. While the following ideas presented do not represent an all inclusive checklist, sufficient thought and preparation will help to lessen the dangers of the venture.
Norway—The Dilemma of a Small Country Torn Between National and International Energy Interests
Authors: Frognes Gunnar 
Published: December 2007

SUMMARY
The objective of this paper is to show how petroleum discoveries and an increasingly important continental shelf may conceivably influence the standing of a small nation in the international community.
Norway is a small and remotely located country, traditionally endowed with few natural resources. For years she has enjoyed the privileges of a small state, being of moderate international prominence, inoffensive to neighbouring states and having a sheltered existence within the framework of a military alliance, all factors giving her "freedom from error" and a fair amount of flexibility in foreign affairs.
In 1968 oil was discovered in the Norwegian part of the North Sea, and since then oil and gas fields have been developed and petroleum reserves gradually built up. To-day, Norway produces petroleum from the North Sea at a rate seven times her own consumption, which is rather unique for an industrialized country. The introduction of economic zones in the seventies, giving coastal states exclusive economic rights in an area extending 200 nautical miles off their shores, has further enhanced the resources potentially available to Norway. Depending on developments in the international energy markets, she may now become an important supplier of energy, especially of natural gas to Western Europe.
Considering the foreign policy and military dimensions of energy security, Norway may, more or less against her will, find herself at the focus of critical energy issues. The situaton is not made easier by the fact that the maritime areas under Norwegian jurisdiction seem to become increasingly important from a military point of view. The stronger this international dimension becomes, the more difficult it will be for Norway to have an influence on developments and defend her interests. Norway may have to take a stand on controversial issues which most small countries can keep at a comfortable distance.
Review of the Completion Practices in the Morrow Formation in Eddy, Chaves and Lea Counties of Southeast New Mexico
Authors: Pai Vithal J. , Garbis Sam J. 
Published: December 2007

ABSTRACT
The Morrow formation is one of the main targets of the drilling activity in Southeast, New Mexico. This paper presents background information including formation lithology derived from X-Ray diffraction data and scanning electron micrographs. Formation rock characteristics such as frac gradients, permeability, porosity and formation water properties are also presented. Completion techniques such as cementing practices, casing programs and perforating programs are reviewed. The stimulation fluids, volumes, injection rates, and types of proppant used are presented to provide an optimum completion program.
Completion Practices and Reserve Estimates for Pecos Slope Abo Gas Field
Authors: Boneau David F. , Braswell Joe , Stall Albert R. , Tisdale Robert E. 
Published: December 2007

ABSTRACT
Yates Petroleum has developed successful drilling and completion practices through experience with 200 wells in the Pecos Slope Abo gas field. Several methods have been used for estimating ultimate reserves from the wells in this low permeability reservoir. The most promising is a drawdown analysis that matches computerized type curves with data on daily flow rates and tubing pressure.
Formation Damage Potential from Carbon Dioxide—Crude Oil Interaction
Authors: Smith Gerald H. , Patton John T. 
Published: December 2007

ABSTRACT
The rapidly expanding use of carbon dioxide, CO2, to enhance the production of crude oil has given rise to reports of apparent formation damage covering a wide range of oil and reservoir properties from different parts of the United States. In 1979 research was initiated at New Mexico State University to define the causes and re-commend solutions to the CO2 formation damage problems. One plausible damage mechanism concerns the precipitation of organic particulates as CO2 dissolves in the reservoir crude.
Three crude oils from pilot CO2 tests were studied to determine their tendency to form precipitates at their respective reservoir pressure and temperature. The three crudes selected for study were a Wilmington crude (California), a Maljamar crude (New Mexico) and a Hilly Upland crude (West Virginia).
To estimate formation damage potential for individual crude oils, volumetric flow versus time through an 8 micron absolute filter has been recorded for the crude saturated with CO2 at temperatures in the range of 77°–123°F (25°–50.5°C) and at pressures in the range of 300–1800 psig (3–18 MPa). The results, surprisingly, show no correlation with the asphaltic content of the crude, previously determined by inducing precipitation by the addition of either pentane or hexane to the crude.
Maljamar crude oil was the only crude that produced CO2 precipitated organic type particules. This crude was subjected to tests in an unconsolidated sand-pack to quantify its damage potential. Under tertiary recovery conditions a permeability reduction of 25% was observed even after 29% of the residual oil had been displaced. Under conditions simulating CO2 secondary recovery (no previous waterflood) some permeability reduction was observed. The relative permeability to water at residual oil saturation was 34% lower using CO2 as a secondary recovery phase as compared to a conventional waterflood.
Considerations For Designing Workover Operations With Continuous Coiled Tubing
Authors: McReynolds A. S. 
Published: December 2007

ABSTRACT
The use of continuous coiled tubing to perform various types of remedial treatments or workovers has been well documented.1,2,3,4 Numerous successful treatments have been obtained with this device in oil, gas, injection and geothermal wells. However, the occurrence of and, more importantly, the causes of failures in operations involving coiled tubing have not been addressed by the industry. An examination of causes of failure should lead to a higher success ratio.