bluuebunny/crossref_metadata_2025_split huggingface dataset:
Response-Time Testing for Subsea Controls in the Cadlao Field
Authors: Manuel W. S. , Hall J. E. 
Published: December 2007

ABSTRACT
This paper describes the response time properties of the direct hydraulic control system for the subsea Christmas trees installed in the Cadlao Field, offshore Philippines. Experimental testing simulated 29 different operating conditions to verify analytical predictions, to demonstrate the effectiveness of applying a common boost pressure to the spring chambers of the gate valve actuators, and to collect data for future applications. Actual data are presented and various relationships defined. With the use of boost, direct, closed hydraulic circuits with ganged functions offer a viable control method for distances up to 3 miles.
Pressure Buildup Analysis for a Well Produced at a Constant Pressure in a Naturally Fractured Reservoir
Authors: Ohaeri C. U. 
Published: December 2007

ABSTRACT
The objective of this study is to present the pressure build-up behavior of a well located in a naturally fractured reservoir and produced at a constant well bore pressure. The flow period response is presented to preserve continuity. By a fractured reservoir we mean a reservoir con-sisting of two systems of porosity and perme-ability: a primary system which is the rock matrix, and whose properties were determined by the depositional environment, and a secondary system of fissures of induced properties. The latter is usually assumed to be the result of post depositional geologic events. Furthermore, the properties of a naturally fractured reservoir are such that the storage properties are associated with the matrix while the conducting properties are due largely to the fracture network. In this study, we consider the model with unsteady state fluid transfer from matrix to fracture. The matrix elements are assumed to be cylindrical in shape. We present analytical solutions for the flowing period and also for the build-up period. It is shown that a plot of the wellbore shut-in pressure divided by the flowing rate at the time of shut-in versus the shut in time on semi-log paper may have up to three straight line segments with character-istic slopes. However, all three straight line segments will be evident only for certain combi-nations of reservoir properties and flowing time. These slopes can be used to obtain reservoir (matrix and fracture) properties.
Impact of Rapidly Changing Economic Environment on Petroleum Exploration and Acquisition
Authors: Schaefer G. T. , Powers L. W. 
Published: December 2007

ABSTRACT
In the last decade, the petroleum industry has experienced the most strenuous growth cycle in recent memory. Beginning in 1973, it enjoyed a period of unprecedented growth until late 1981 when a precipitous decline was initiated. This downturn, which was unforeseen by most organizations and individuals, has adversely affected many including investors, operators, equipment suppliers, and the financial community.
This paper will put this rapidly changing environment into perspective by illustrating the historical relationships between price changes in actual and real terms, activity levels, energy supply/demand and petroleum reserves in U.S.A., all of which have had significant impact on the investment outlook of the petroleum industry. It will demonstrate that rapidly rising prices in last decade elevated expectations of return on investments in the oil and gas industry. For the investor, this became a seller's market where the investor generally took what the operator offered with marginal room for negotiations. High activity levels often resulted in higher than anticipated costs and when complemented with sudden downturn in prices, caused many programs to generate less than desired results. By relating average 1980–81 industry finding and acquisition costs to after-tax rate of return on investment based on actual exploration and acquisition programs, this paper will illustrate why many investors became disappointed with these programs. This explanation will take into account economic factors such as federal income tax changes, excise tax (windfall profits tax), price and market changes as well as exploration and development costs.
Based on this actual data and information, the relationships between after-tax return on investment and both finding and development costs and acquisition costs will be graphically illustrated for several future oil and gas pricing scenarios. Comparisons are provided to illustrate the tax benefits associated with exploration and development vis-a-vis acquisition. In addition, examples will be given to demonstrate the various factors which result in different rates of return for similar acquisition costs. In effect, using this information, analysts will be able to do a better job of screening future programs without doing a tedious, detailed analysis. This information should be useful to anyone involved in economic decisions within the petroleum business, especially management, consultants, bankers and investors.
Acquisition and Enhancement of Mature Producing Properties: A Case History
Authors: Artus D. S. , Solmonson D. W. 
Published: December 2007

ABSTRACT
This paper describes the three year history of an independent oil company formed to purchase and enhance producing properties. The application of detailed field studies and conventional enhancement techniques has resulted in increased proven reserves and substantially increased cash flow from the properties in spite of the decline in oil prices.
Total investment in the properties to through 1982 was $41.3 million with an additional $16 million remaining to be spent if all identified enhancement projects are implemented. Pre-tax rates of return for the total acquisition program are expected to be in the 24 to 28 percent range.
Foam Fracturing Laboratory
Authors: Wendorff C. L. , Earl R. B. 
Published: December 2007

ABSTRACT
A new laboratory has been constructed with test equipment designed to expose foam fracturing fluids to test conditions simulating treatment conditions of shear, time, temperature and pressure during the tests. The goal for designing this laboratory was to simulate treating and downhole conditions as closely as possible and to determine fracturing foam properties under these conditions. This paper describes the design parameters and equipment in this unique laboratory.
A New Crosslinked Foamed Fracturing Fluid
Authors: Watkins E. K. , Wendorff C. L. , Ainley B. R. 
Published: December 2007

ABSTRACT
The technology of stabilizing foamed fracturing fluids has been extended to include the use of cross-linked gels as foam stabilizers. Gasified treating fluids prepared from these gels have unique properties which differentiate them from both traditional foams and gels. Traditional foams require that the gas/volume ratio be greater than 0.52 in order to obtain a stable foam structure. Such high gas ratios produce foams with low fluid densities and low proppant concentrations. Using crosslinked gelled fluid as the stabilizer for foams, very stable dispersions of gas in liquid can be prepared with almost any gas content. Stable foams having a gas/volume ratio (GVR) greater than 0.52 as well as stable energized fluids having a GVR of less than 0.52 can be prepared. Stable energized fluids containing less gas can have appreciably higher fluid densities and proppant concentrations. This paper describes the properties of foams stabilized with crosslinked gels, their broadened uses in stimulating wells and the results of treatments.
Optimizing Surfactant Molecular Weight Distribution I. Sulfonate Phase Behavior and Physical Properties
Authors: Salter Stephen J. 
Published: December 2007

ABSTRACT
In this paper experimental results are presented in an investigation of surfactant-oil-brine phase behavior and physical properties. The question of whether single-component surfactants are preferable to diverse mixtures is addressed both from the stand-point of oil and brine solubilization, as well as surfactant component fractionation. This investigation includes a detailed study of the phase behavior of a monoisomerically pure sulfonate, a pure hydrocarbon, water, and sodium chloride. Conclusions are reached regarding both the complexity of the global phase behavior of this system and the number of components necessary to describe this phase behavior.
The phase behavior for mixtures of nonoisomerically pure surfactants is then compared to the single-component results. The degree of sensitivity to the composition of these mixtures is shown to be very high. An hypothesis is presented, and supported by experimental data, in which the mechanism that controls surfactant component fractionation is proposed. This mechanism relates the importance of structure formation to surfactant fractionation. Results are presented for five component systems (oil, brine, and two surfactants) that illustrate the shape of the three-phase region in phase-space, and the movement and alteration of this region with changes in salinity.
Observation, Prediction, and Analysis of a Laboratory Two-Well Chemical Flood
Authors: Haskin H. K. 
Published: December 2007

ABSTRACT
The concept of volumetric linear scaling was developed to provide a simple oil recovery prediction procedure that adequately described the important aspects of chemical flooding for single and multiple slug systems. This approach has been used successfully to model several chemical flood systems in both field cores and synthetic rock.1,2 When coupled with a flow description, linear flood oil saturation data have also been used to predict oil recovery performance of laboratory pattern floods.3,4
This simple scaling approach will be used here to describe chemical flood performance in a novel unconfined laboratory flood monitored by a microwave saturation scanner. An unconfined two-well geometry was chosen for study because it provided a severe test of the simple streamtube flow description employed. A two-well pattern also represents the simplest of the class of small isolated patterns sometimes employed in field pilot tests. Interpretation and modeling of these isolated patterns has historically been difficult. Extension of the scaling theory to a two-well pattern would provide the engineer with another tool for analysis of such floods.
Ten curvilinear unit mobility streamtubes were employed to describe flow in the laboratory experiment. Predictions of 2-propanol saturations measured during miscible injections in the two-well model were compared to observations to check the validity of the streamtube net. Expected effects of the two-well geometry on oil recovery from the laboratory model are discussed in light of the large variation in size of the individual streamtubes in the flow description.
Oil saturation profiles were measured during a linear chemical flood involving injection of a small surfactant slug followed by a small polymer slug and continuous drive brine. These So profiles were then scaled along the unit mobility streamtube net. Oil saturation contours, endpoint conditions, oil breakthrough time, and oil production history predictions were made. Comparison of these predictions to the observed performance of the eight day chemical flood carried out in the large two-well model indicate that the scaling concept can be used to model this type of flood. The fixed streamtube description served as a useful first approximation for the unconfined pattern geometry even in the presence of observable crossflow between stream-tubes.
The Flow Of Foam: I. Rheology And Streaming Potential
Authors: Raza S.H. , Marsden S.S. 
Published: December 2007

Abstract
This, paper presents an experimental study of the flow behavior of foam through capillary tubes as well as a theoretical and experimental study of the streaming potentials generated during the flow. Important parameters such as the pressure differential, the quality of foam, the electrochemical nature of the surface active agent and the dimensions of the capillary tube have been investigated and a physical model describing the experimental results is presented. Foams were produced from aqueous solutions of various surface active agents in a foam generator of novel design. The flow media studied were:
capillary tubes of several diameters, a capillary tube packed with glass beads slightly smaller in diameter than the capillary tube, and a capillary tube filled with crushed pyrex glass.
The quantities measured were foam flow rate, foam quality (ratio of gas volume to total volume of foam), streaming potential and streaming current. As indicated by the general overall shape of the pressure differential versus flow rate plots, the flow of foam in capillary tubes is quite similar to that of pseudo-plastic substances.
The Real-Time Calculation of Accurate Bottomhole Fracturing Pressure From Surface Measurements Using Measured Pressures as a Base
Authors: Hannah R. R. , Harrington L. J. , Lance L. C. 
Published: December 2007

ABSTRACT
Several papers written since 1978 have addressed the inportance of an accurate knowledge of bottom hole fracturing pressure. Nolte and Smith1 in 1979 focused industry attention on the value of this information in predicting fracturing conditions. By the proper interpretation of the slope of log net fracture pressure versus log time, they showed that normal extension with confined height, fracture height growth with extension, loss of fluid loss control due to hairline fracture openings, and runaway growth of fracture height could be interpreted for fractures conforming to the fracture geometry of Perkins and Kern2 and Nordgren3. Nolte4, in another paper, demonstrated that post-fracturing pressure decline data could be used to predict certain other fracturing parameters such as fracture height, leak-off coefficient, length, width, and closure time. Papers dealing with this technique include those of Veatch and Crowell5, Schlottman, et al6, Dobkins7, Smith8 and Smith9. Nolte, in 1982, wrote an excellent paper summarizing these techniques in SPE paper 10911, "Fracture Design Considerations Based on Pressure Analysis."10 Novotny11 also proposed a fracture closure model based on fracture geometry and leak off. Erdle12, et al, discussed the results of an experimental program conducted in Peru that addressed the same topics.
The authors here will not attempt to review or expand on the interpretive techniques given in the literature cited above. This approach has been generally accepted by the industry and dealt with in an excellent manner by the authors listed.
In the cited literature a reference string, either the tubing or the tubing casing annulus, was available to act as a monitor for bottom hole pressure behavior, that is the sum of the indicated surface pressure plus the pressure exerted by the hydrostatic head in the reference string is an accurate reflection of the true bottom hole fracturing pressure. The reference string, while desirable in terms of pressure measurement, presents some problems from both an operational and economic standpoint. In many cases the strength of the tubular goods is insufficient to allow the well to be fractured at meaningful rates with a reference string in the well. For higher pressured wells, treatment down tubing without a packer is many times impossible without casing rupture. In addition, unless the well can be placed in its final production configuration, the expense of tubing trips must also be borne. Where annular treatments are performed there is concern that the presence of the tubing may contribute significantly to shear degradation of the crosslinked gels and that injection rates using this configuration may be limited.10
A Computer Database System Designed for Drilling Information Analysis
Authors: Lacy K. D. , Gill B. B. , Buras K. F. 
Published: December 2007

ABSTRACT
This paper describes a data base system used by Chevron USA's Eastern Region which allows in depth analysis and comparisons of any of the recently drilled Chevron Wells. Compared to previous methods of record keeping, the new system is much more timely and accurate and has reduced the time spent in gathering information when more than one well is reviewed.
Drilling information is input into the data base for each well as the well is drilled. This information is used on a daily basis to produce a drilling morning report for management. Once the well is finished the daily information is compiled and used to prepare a final well report. This report is designed to provide a brief summary of all the highlights and problems encountered along with final costs and performance curves for each new well. Not all of the information entered into the data base is used in the final well report. This information however remains in the data base where it can be accessed to help in planning offset wells, evaluating drilling problems, and making special studies.
This paper covers the development of the data base and gives information useful to those who may want to set up a similar system. The format of the daily drilling report and the final well report is given along with examples of the reports that can be generated using information from the data base. A system similar to the one developed by Chevron should be very useful to anyone involved in drilling operations. The system need not be limited to drilling information and can easily be changed to include information others feel is relevant to the well file.
New Methods for Locating the Moving Gas/Water Boundary in Underground Storage Reservoirs
Authors: Udegbunam E. O. , Tek M. R. 
Published: December 2007

ABSTRACT
Methods have been developed which permit the calculation of the approximate position of the moving gas-water boundary in underground gas storage reservoirs from data on storage pressures and distant observation well liquid levels.
Locating the gas-water boundary in underground storage is important in control of gas bubble growth and in monitoring against possible migration away from storage horizon. The mathematical procedures developed permit calculation of gas-water interface location as a function of time as it moves laterally in response to storage operations. Reasonable results and agreement with observations were obtained from the model using reservoir data from a large storage field. The sensitivity of results to possible errors in the reservoir data and the effect of location of the available key storage well are shown to provide practical guidelines defining limitations of the mathematical technique.
A Study of Caustic Consumption in a High-Temperature Reservoir
Authors: Simlote V. M. , Zapata V. J. , Belveal L. A. 
Published: December 2007

ABSTRACT
This paper describes a procedure used for evaluating a high temperature reservoir for caustic flooding. A comprehensive feasibility study included reservoir rock and fluid characterization, laboratory measurements of parameters controlling caustic consumption and a process evaluation by simulation with a finite difference chemical model. A two phase, six component finite difference chemical model was modified to include the long term caustic consumption based on first order reaction kinetics. The model produced a satisfactory match of a laboratory experiment conducted for determining caustic consumption. The influence of ion exchange, slug size and flow rates on the propogation of an effective caustic concentration through the reservoir was also investigated.
The study indicated that caustic flooding of a high temperature reservoir can be successful only if the reservoir has sufficient flow capacity. To overcome the large caustic consumption due to high temperature, a high velocity must be maintained. Concentration of the caustic is also critical. However, if the fluid cannot be propogated fast enough, the concentration becomes insignificant.
Recent Changes in the Natural Gas Industry and the Potential Shape of its Future: A Regulatory Perspective
Authors: Essley P. L. 
Published: December 2007

ABSTRACT
From 1954 through 1981 the retail price of most natural gas in the interstate market was equal to the sum of a regulated wellhead price, a regulated transportation cost, and a regulated distribution cost. The profits of each segment of the natural gas industry were controlled by regulators and were essentially independent of the profits of the other two segments. Currently, the sum of the prices allowed by regulators exceeds the price the marketplace will allow. The various sectors of industry must now compete against each other for a share of the consumer's dollar. The industry practices that developed during the past regulated environment are proving to be inefficient in the new competitive environment of the 1980s. As a consequence, the industry structure and practices will change.
Multiphase Flow in Porous Media: III. Oil Mobilization, Transverse Dispersion, and Wettability
Authors: Mohanty Kishore K. , Salter Stephen J. 
Published: December 2007

ABSTRACT
A pore-level, three-dimensional network model is presented in this paper to calculate transverse dispersion and residual oil saturation at high capillary number floods in strongly wet media and many transport properties in mixed wet media. These transport properties are capillary pressure, relative permeability, and mixing parameters. A technique has been developed to generate well controlled mixed wettability in sandstones. Model predictions are compared with experimentally obtained values of transport coefficients. Our results illustrate the effect of wettability on transport properties of a rock.
Multiphase Relative Permeability Measurements Using an Automated Centrifuge
Authors: O'Meara D. J. , Lease W. O. 
Published: December 2007

ABSTRACT
The automated centrifuge uses a linear photodiode array in conjunction with a microcomputer to image and identify liquids recovered from centrifuged rock samples. Compared to previous centrifuge measuring techniques this new system Obtains and analyzes production data electronically, thus requiring little human intervention.reduces inaccuracies in measurementsallows for collecting initial data when liquid levels are changing rapidlyprovides for easy corrective action if problems occur during an experiment.
Typical raw data along with calculated realtive permeabilities are shown for both two-phase and three-phase experiments.
Enhanced Load Water-Recovery Technique Improves Stimulation Results
Authors: Penny G. S. , Soliman M. Y. , Conway M. W. , Briscoe J. E. 
Published: December 2007

Abstract
The roles of capillary pressure, wettability and relative permeability in controlling load water recovery following hydraulic fracturing treatments have been examined. It has been found in laboratory studies that the judicious alteration of wettability to control capillary pressure and/or relative permeability can promote a rapid thorough cleanup of injected water. Field applications employing these concepts have resulted in enhanced load water recoveries and higher production due to longer effective frac lengths and/or higher fracture conductivities following cleanup.
The Simulation of Water-Injection Performance for a Well with a Propagating Fracture
Authors: Cottrell C. W. , Al Baker S. A. 
Published: December 2007

SUMMARY
A method of numerically simulating the water injection performance of a well with a propagating fracture has been developed. The fracture propagation is modelled by adjusting the well completion to include grid blocks laterally displaced from the centre of the well. For a multilayered system any required fracture shape and development with time can be accommodated.