bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Energy Balance Concept of Hydraulic Fracturing
Authors: Perkins T.K. , Krech W.W. 
Published: December 2007

Abstract
This paper explains the concept of a damaged region arising from high stress concentration at the leading edge of a hydraulically created fracture. Approximate stresses near the tip of the crack are calculated, and it is shown that a stable crack shape is possible for which all stresses are finite. A new energy balance is derived incorporating these thoughts, and it is shown that predicted fracturing pressures (using surface energies determined by cleavage) agree with experimental fracturing pressures determined in models. All calculations apply to the case of a nonpenetrating fluid. It is concluded from these studies that in some cases, particularly in small laboratory models, these phenomena significantly affect extension pressures and crack widths.

Introduction
One of the perplexing questions about hydraulic fracturing that has not been satisfactorily answered is, what pressure is necessary to extend a fracture? For many engineering problems involving failure, it is sufficient to calculate those loading conditions which would bring a stress or elastic strain within the material to a level that could not be tolerated. However, this approach is not useful when considering a sharp-edged crack; calculated stresses and elastic strains always reach infinitely large values near the tip of the crack if fluid pressure is applied all the way to the crack extremity. This difficulty has led to the concept of cohesiveness or absorption of surface energy, implying that behavior near the tip of the crack is not purely elastic.
Additional note of the nonideal behavior of rocks will be made in this paper. Then, by simplifying and dealing with an average stress in an inelastic region, the approximate stress distribution around a hydraulic fracture will be calculated and the conditions under which a stable fracture can exist will be shown. A new energy balance equation is then derived incorporating the modified stress picture. Finally, predicted fracture extension pressures are compared with breakdown pressures obtained in laboratory models. This comparison shows that surface energies measured by the cleavage technique are consistent with those values manifested during fracture extension.

PROBLEMS OF INDUCED STRESS
It will be revealing to consider first the calculated stresses around a penny-shaped line crack, assuming that the rock behaves as a linear, elastic material. Fig. 1 shows the stress distribution in the plane of the crack as calculated with Sneddon's equation. If pressure p is applied uniformly within the crack, then infinitely large tensile stresses would be induced in the rock near the crack tip. Such stresses could not be sustained in a real material. Two approaches have been proposed to explain this dilemma.
SPEJ
P. 1ˆ
Pseudolimited Entry: A Sand Fracturing Technique for Simultaneous Treatment of Multiple Pays
Authors: Stipp Louis C. 
Published: December 2007

Abstract
Tenneco Oil Co. has used the pseudolimited entry technique to simultaneously and effectively sand-water fracture the multiple, hard, tight Dakota gas pays in the San Juan basin. Application of this technique involves
the use of ball sealers to insure that a satisfactory number of perforations are open prior to fracturing, employment of a low (approximately 300 psi) perforation differential to insure simultaneous, effective stimulation of all perforated pays of approximately equal fracturing pressure and the use of bridge plugs when necessary to insure stimulation of zones having significantly different fracturing pressures.
The use of the pseudolimited entry technique essentially has eliminated sand-outs, poor treatment coverage and other problems associated with other fracturing techniques. As of March, 1966, the absolute open flow potentials (AOFP) of the nine wells completed by this method averaged over 4,000 Mcf/D or 78 percent above those AOFP's of conventionally treated offset wells. Constantrate pressure drawdown testing' also has supported the results attained.
The results and continued use of this technique have proved it to be an effective method for stimulating the Dakota pays of Northwest New Mexico.
Introduction
Fracturing multiple pays with conventional techniques (densely perforated zones, treatment control through the use of bridge plugs or ball sealers) can result in expensive or marginal completions. Fracturing the Dakota formation in the San Juan basin with conventional methods offers few exceptions to this.
The Dakota formation in the San Juan basin is approximately 200 to 300 ft thick. As shown by Fig. 1, it often is composed of multiple, hard, low-porosity, gas- bearing sands separated by shale. At a given location, the lower Dakota usually is composed of a series of sands of approximately equal fracturing pressures. These pressures often vary markedly between locations. The middle and upper Dakota sands are less numerous. They have approximately equal fracturing pressures significantly different from those of the lower sands; those of the middle and upper sands also can vary over a short distance. Fracturing pressures of all the Dakota sands are difficult to predict quantitatively.
The Dakota frequently is sand-water fractured with conventional multistage treatments, employing bridge plugs or ball sealers for treatment control and diversion. Normally, the amount of propping agent used is between 50,000 and 100,000 lb of sand. Treating rates usually are between 35 and 50 bbl/minute. In many cases individual sands will be perforated with so many holes that the treatment will be accepted into the sand that has the lowest fracturing pressure.
JPT
P. 457ˆ
Infill Drilling in the Rotherwood Field, Harris County, Texas
Authors: Hurst William 
Published: December 2007

Summary
More than 600 billion bbl of oil are estimated to be left behind in abandoned and producing fields. The average field produces only one-third of the oil originally in place. This paper describes a method to determine where this oil exists in odd-shaped fields like the Rotherwood field in Harris County, TX. Conformai mapping is used. The field's configuration is changed to a conformai rectangle where Basset's formula for fluid flow between parallel planes applies. By this means, streamlines are developed showing the directions of oil movement to the producing wells in the reservoir. Where large gaps appear between streamlines, or where any abnormalities are evidenced, an area of unproduced oil exists.
Gas-Lift Allocation From Workstation Data Base
Authors: Woodyard A. H. 
Published: December 2007

Summary
Since installation of Conoco’s artificial-lift allocation program (COALA) in mid-1988, engineer productivity has increased significantly over traditional gas-lift techniques. COALA is a series of gas-lift engineering programs integrated on a PC. The programs use a companion relational data base for troubleshooting, production maintenance (through review of flowing survey analysis), and performing system analysis. Optimum gas-lift allocation rates are identified by well and field. Reports on well data can be generated as the engineer sees fit.
Cyclic Steam Injection Project Performance Analysis and Some Results of a Continuous Steam Displacement Pilot
Authors: Adams R.H. , Khan A.M. 
Published: December 2007

Introduction
The Huntington Beach oil field is on the Pacific Coast, southeast of the City of Los Angeles (Fig. 1). It lies both onshore and offshore. Most of the onshore section is operated by Standard Oil Co. of California, WOI. The Tar reservoir is of upper Pliocene age, about 200 ft thick, and consists principally of fine-grained, unconsolidated, somewhat shaly sand, with thin interbedded shale stringers throughout (Fig. 2). The reservoir is a broad, highly faulted, elongated anticline, with an areal extent of about 370 acres. Most of the faults bisecting the structure are normal, trend north-south, and are the main cause of reservoir discontinuity (Figs. 3 and 4). From 1964 to Dec., 1967, 259 steam stimulations were performed on a total of 125 Tar sand wells. Eighty-six new wells were drilled and steam stimulated. Of the total, 96 have been stimulated twice, 34 three times and 3 four times. During this same period, a two-injector steam drive pilot has been in progress. The response obtained from this project has been compared with the response to cyclic stimulation. This paper presents an analysis of the field observations for the two methods of thermal recovery.

History of Development
Drilling to the Tar pool commenced in 1924 with an initial well production of 40 to 50 B/D of 12 degrees API gravity oil. Complete primary development of the pool has been spread over several years. Approximately 40 wells were drilled during the first phase of development, which was completed in 1945. The subsequent primary development started in 1960 with initial well productions of 30 to 40 B/D oil. Thirtyseven wells were completed in the Tar pool during this phase. For the most part, slotted, gavel flow packed liners have been used in the wells in this pool. A cyclic steam stimulation pilot was initiated in March, 1964. Based on the very successful stimulation in the pilot area, the cyclic stimulation project was expanded to include all of the Tar pool wells producing at the end of 1965 (Fig. 5). Also, a development drilling program was begun at this time. To date, 86 new wells have been drilled under this program. The number of wells drilled each year in this secondary phase of development is also shown in Fig. 5.

New Well Completion Practices
Most of the new wells have been completed to produce from both the Upper and Lower Tar zones. Generally, a casing stub is cemented from the top of Lower Tar to the base of clean Upper Tar sands to exclude intermediate water-bearing sands. The water string is then cemented from the top of Upper Tar to about 1,500 ft with neat cement and 30 percent silica flour. The annulus from 1,500 ft to surface is then filled with a petroleum-based gel through a hightemperature port collar. Once again, a history of sand-free production dictated the use of 60-mesh gravel flow packed liners.
JPT
P. 95ˆ
Accuracy of Offshore Subsidence Measurements With Seabed Pressure Gauges
Authors: Mes M. J. 
Published: December 2007

Summary
Phillips Petroleum Co. Norway pioneered the application of pressure gauges to measure offshore platform subsidence histories. Four pressure-gauge systems were installed in the Greater Ekofisk area. Prototype data prove that the progression of subsi dence can be measured with pressure gauges with a relative uncertainty of ±9 mm.
A Lease Consolidation, Telemetering and Supervisory Control Project
Authors: Abel W.L. , Pace F.A. 
Published: December 2007

Abstract
Pan American Petroleum Corp. has applied the latest techniques of tank battery consolidation and automation to control oil production from the East Texas field. A major part of this project was the consolidation of 93 leases comprising 913 wells under a central automatic custody transfer (ACT) system. This consolidation makes maximum use of the pipeline company's crude-gathering system that also handles and commingles the production from 45 outside-operated leases run by conventional tank-gauging methods. The second part of the project is a data acquisition, telemetering and computer-interfaced supervisory control system. The central control for this system is located in Tyler about 40 miles west of the East Texas field. Lease production is scheduled, controlled, accumulated and formally reported from the central control, which also monitors equipment operations and relays malfunctions to pumper patrols.

Introduction
The East Texas automation project includes 974 wells on 101 leases covering a 55 sq mile area in the north half of the East Texas field. About 95 percent of the wells are flowing and produce pipeline oil. The remainder are produced by electrically operated pumping units. Oil production in the field is obtained from the Woodbine sand at a depth of approximately 3,300 ft. It has been producing for 30 to 35 years and has a remaining estimated life of 70 years. Average well density is less than 5 acres/well. Because of this density and because of the depth of the sand, the top allowable is 20 B/D, subject to market demand factors. The average well produces its allowable when flowing on a schedule of approximately 30 minutes/ day, 3 days a week.
Development and Application of a Microcomputer Monte Carlo Simulation Model With Lotus 1-2-3
Authors: Yu John P. , Zhuang Ziqing , Watts Royal J. 
Published: December 2007

Summary
A microcomputer Monte Carlo simulation model to perform economic evaluation of CO2 miscible flooding projects has been developed with Lotus 1-2-3. This study includes risk simulation using the Latin hypercube sampling technique. The risk-simulation model is completed on the spreadsheet, with keyboard macro enhancing the feasibility and application of this model. A risk-weighted discount cash flow (DCF) rate of return, profit/investment ratio, net present value, and payback periods were obtained.
The risk-simulation model is very user-friendly. It can perform statistical analysis and generate tables and graphs for result presentations with Lotus 1-2-3 macro enhancements. In addition, the model can be modified to suit any other specific field case applications—e.g., exploration and drilling.
A Microcomputer-Based Log-Analysis Program in a Windows Environment
Authors: Rubenstein Jeff D. , Harder Steven M. , Barba Robert E. 
Published: December 2007

Summary
In the past few years a number of software programs have been developed to process openhole wireline data on PC’s, but most require extensive computer experience or training to operate. At the same time, PC operating systems have evolved to incorporate graphical user interfaces. The QLA* program integrates a loganalysis package with one of these new operating systems using the Microsoft Windows™ operating environment for IBM- compatible computers. Programs run under Windows use a "visual interface" and can be executed with a minimum of keystrokes by use of a mouse and pull-down menus. All options are readily displayed to the user, and a minimum of program knowledge is required to integrate log graphics, crossplots, reports, and text into a single document.
Quantitative Use of Calibration Data to Correct Miscalibrated Well Logs
Authors: Maciula E.A. , Cochrane J.E. 
Published: December 2007

Abstract
A method of mathematically correcting miscalibrated well logs on the basis of calibration data is presented. The model is a logging system with a linear-response function calibrated to two standards. The model assumes that interaction between calibration error functions is negligible, and that these error functions remain essentially constant during the log recording.
The general model and the resulting correction equation were adapted to induction logging systems, and field Trials were performed to test the validity of the model. A computer program permitted induction log data to be generated continuously through the correction equation. Results indicate the assumptions are reasonable, and that adequate correction is accomplished for the range of conductivity values investigated.
The correction technique was applied to induction logs run by four service companies in the same wellbore in the Wilmington field, Calif. The corrected logs essentially are identical.

Introduction
Well logs formerly were used primarily for qualitative formation evaluation and correlation. Log accuracy has become of prime importance as logging has begun to provide quantitative parameters for the determination of formation characteristics. Measurement accuracy is dependent upon precise logging-system calibration. However, little attention has been paid by oil companies to these calibration data, and use of these data has been confined to intercompany accuracy control by the logging companies. Recently oil companies have come to realize the dependence of competent formation evaluation on accurate logging system calibration. With the nascence of this interest in highly accurate logs, we foresee advantages to be gained from a method through which a miscalibrated log can be corrected adequately on the basis of calibration information. Such a method would enable the company witness to accept such a log if he were provided with a complete calibration record. This latitude would prove especially profitable where hole conditions are severe or when rig time is a critical consideration.
A mathematical technique is proposed for correcting erroneous logs that are produced by logging systems having a linear response characteristic and calibrated to two standards. To simplify the model, assumptions were made concerning interaction of high- and low-error components. The ideal model has been adapted to fit the induction logging system. Field tests, utilizing purposely miscalibrated induction logs, were conducted to test the validity of the revised model. Results of these tests indicate the equation is correct for usual conductivity ranges observed in California formations. A computer program has been written to generate a corrected induction log using error inputs calculated from the calibration records.
Determination of Steam Quality Using an Orifice Meter
Authors: Palm J.W. , Kirkpatrick J.W. , Anderson W.H. 
Published: December 2007

Abstract
Steam generators used to inject steam into petroleum reservoirs are designed to produce wet steam, usually about 80 percent quality. For economical operation the steam quality should be continuously monitored, which can be done using an orifice meter. In addition to using data for flow of the generator effluent through an orifice, the method uses the flow rate of water to the generator as measured independently, such as by a positive displacement meter.
An improved calculation method has been demonstrated at pressures of 129 psig and 300 psig with qualities, of 32 to 100 percent. The calculation method is based on a literature correlation that includes data at pressure up to 929 psia. The method is expected to be useful at higher pressures as long as the volumetric gas-liquid flow ratio and the ratio of mass flow rate to pressure are above specified minimum values.

Introduction
Many references have mentioned or discussed the problem of two-phase flow through an orifice. However, most of the literature has been inaccurate or has not considered all of the important variables in this operation. Calculation methods for wet steam shown in two well known orifice meter handbooks are not accurate. For example, Diehl and Beck use the steam coefficient factor F. and state that the orifice differential is approximately linear with quality at a given pressure and constant total mass flow rate of wet steam. This is incorrect. The square root of the differential is approximately linear with quality.
An accurate and detailed treatment of measuring two-phase flow with an orifice was made by Murdock. He published experimental data that both he and W. H. Osborne had obtained, as well as a correlation of the data, which has a standard deviation of only 0.75 percent. The data included two-phase systems of steam-water, air-water. natural gas-water, natural gas-salt water and natural gas-distillate at pressures of 15 to 929 psia.
Two other recent references give data that are reasonably consistent with Murdock's correlation. However, the data in these references are not complete enough to permit exact comparisons.
This paper illustrates the application of Murdock's correlation to measuring steam quality in thermal recovery operations, and further defines the limitations of the method.
Calculation of Parachors for Compositional Simulation: An Update
Authors: Fanchi John R. 
Published: December 2007

Summary
Published parachor-correlation predictions diverge for high-molecular-weight (MW) components. This divergence stems from a lack of data. This paper incorporates parachor measurements for high-MW mixtures that have not been used in the preparation of previously published parachor correlations into new parachor correlations.
1D Simulation of Polymer Flooding Including the Viscoelastic Effect of Polymer Solution
Authors: Masuda Yoshihiro , Tang Ke-Chin , Miyazawa Masashi , Tanaka Shoichi 
Published: December 2007

SummarySimple simulation models are constructed to predict the performance of 1D polymer flooding. In the models, two phases of oil and polymer solution were assumed to be immiscible with each other. Because the displacing fluid was non-Newtonian, the BucldeyLeverett equation could be modified and a new approach developed to calculate fractional-flow curves. The rheological behavior of polymer solution was modeled with an Ellis type model and a viscoelastic model. To verify the models, two 1D flooding experiments were carried out on 2.8-cm-diameter, 47-cm-long, unconsolidated cores packed with glass beads (70/100 mesh). Porosities of the cores are about 37% and permeabilities are around 26 μm2. Two white mineral oils of viscosities 25 and 60 mPa·s and a 200-ppm polyacrylamide solution were used. In each experiment, polymer flooding was done after waterflooding. Initial water saturation was controlled to be almost the same at the start of each flood. The calculated polymer-flooding performances were compared with experimental data. The Ellis model predicted earlier breakthrough of polymer solution and lower oil recoveries than the experimental data. On the other hand, the viscoelastic model predicted fractional-flow curves, oil recovery performances, and breakthrough times of the experiments very well. The viscoelastic effect of polymer solution is thought to play an important role in the improvement of oil recovery.
The Steam-Foam Process
Authors: Hirasaki George J. 
Published: December 2007

Summary
The steam-foam process was developed to improve the sweep efficiency of the steamdrive and steam-soak processes. Steamdrives that are not stabilized by gravity can have a poor vertical sweep efficiency as a result of (1) gravity overlay in a thick sand with vertical communication and/or (2) channeling in a layered formation with poor vertical communication between sand members. The reduced mobility of steam foam increases the pressure, and gradient in the steam-swept region to displace the heated oil better and to divert steam to the unheated interval. Surfactants reduce the steam mobility by stabilizing the liquid lamellae that cause some or all of the steam to exist as a discontinuous phase. The propagation of surfactant is retarded by ad sorption. In the phase. The propagation of surfactant is retarded by ad sorption. In the case of ion exchange of divalent ions from the clays, the surfactant is also retarded by precipitation and/or partitioning into the oil. The rate of propagation of foam is also determined by the mechanisms that generate and destroy foam. The generation mechanisms include leave-behind, snap-off, and division. The destruction mechanisms include condensation and evaporation, coalescence by a limiting capillary pressure, and coalescence resulting from the presence ofoil. The foam texture can be predicted from a population balance that includes these mechanisms. predicted from a population balance that includes these mechanisms.

Introduction
Scope. This paper reviews the steam-foam process. It is not an exhaustive survey of the literature, and I apologize to the many contributions that had to be omitted because of length limitations.
The types of field application of steam foam are discussed first. Examples are taken from reported pilot results. The remainder of the paper focuses on process mechanisms. Understanding of the mechanisms for foam flow in porous media is still in the formative stage, and many advances can be expected. It is hoped that this paper will help the practicing engineer apply the process more efficiently and will challenge the researcher to advance the knowledge of the process and to develop more efficient formulations.