bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamics of Moving Interfaces in Porous Media: III. Extension of Buckley-Leverett Theory
Authors: Kale Dilip M. 
Published: December 2007

ABSTRACT
In this paper Buckley-Leverett frontal advance theory is extended to two dimensional flows. Two dimensional analog of the front is a closed curve c across which the water saturation changes abruptly. Behind the front water saturation increases monotonically towards the injection well. Equisaturation contours behind the front are also closed curves. The continuous change in water saturation is approximated by several small steps. Then we get several equisaturation zones behind the front separated by contours across which water saturation changes abruptly in small steps. We shall refer to these contours as fronts. This approximation corresponds to linearizing the fractional flow curve beyond the frontal saturation by several linear segments.
The progress of the fronts with time depends upon the well configuration and the fractional flow curve. The total mobility changes across each front giving rise to a vortex sheet. A complex velocity potential for the instantaneous velocity field is constructed by the method developed in the earlier papers and the efflux vector is found out everywhere in the flow region. The velocity with which the fronts advance is in the same direction as the efflux vector, but the magnitude of the former differs from the latter by a factor Fw' = dFw/dSw evaluated at the corresponding water saturation. Knowing the velocity of the front it can be traced in time. In other words, after finding the efflux vector in the flow region, in an infinitesimal portion of the flow region we can apply the theory of frontal advance by assuming the flow to be linear there. The procedure of calculations is demonstrated for a typical fractional flow curve with some simple well patterns.
An Engine Concept for a Viable Transition Into the Future
Authors: Eng K. D. 
Published: December 2007

Abstract
Syncrudes and synfuels will be introduced in the future to supplement or replace petroleum based transportation fuels. Initial synfuels may have qualitites considerably different from present fuels and may cause operational problems in engines. Instead of further treating the synfuels to meet current fuel specifications, thus increasing the production costs, it is entirely viable to introduce an engine which has the capability of operating on a broad range of fuels. This type of engine, with its ability to run on petroleum based fuels and synfuels, could provide a smooth transition into the future.
The Texaco Controlled-Combustion System (TCCS) is a direct-injection, stratified-charge, engine concept. It has demonstrated the ability to run on a broad range of fuels including gasoline, diesel, broadcut fuels, low octane shale derived gasoline and alcohols. Performance of an engine modified to employ the TCCS concept, operating on different fuels, is discussed in this paper.
Exploration for Natural Gas in Northern Germany and in the Alpine Area
Authors: Hedemann Hans-Adolf 
Published: December 2007

Abstract
During the sixties, natural gas fields in carbonate reservoirs of the Sechstein formation (Upper Permian), in particular, were developed in the North German basin at depths of 2 000 - 4 000 m (about 6 500′ - 13 0001). Current exploration is focussed on Rotliegendes sandstones (Lower Permian) at about 5 000 m (16 400′). Successful discoveries are being developed. In some places natural gas has been discovered below the Permian in sandstones of the Upper Carboniferous (Pennsylvanian), the coalbearing source formation for the gas. With the development of gasbearing Paleozoic and deeply buried sandstones, the problems of tight reservoir rocks became evident. Stimulation of these rocks requires super-frac operations.
Throughout the present phase of active development, exploration geologists have in mind that exploration in future decades will be looking out for potential natural gas prospects in Devonian and/or Lower Carboniferous (Mississippian) of the North German basin. This has already happened in the eastern part of Germany. Such targets occur at depths of about 7-8 000 m (23 000′ - 27 000′). Geophysical surveys and some wildcat drilling, partly supported by governmental funds, have been carried out, some of which by major joint ventures.
Similar subsidies are given for exploration of deep targets (6 - 8 000 m, 20 - 27 000′) in the area of the Northern Alpine thrust zone in Bavaria. In the Northern Alpine Foreland, however, only small to medium natural gas fields at depths of between 1 000 and 3 000 m (About 3 000 - 10 000′) have so far been developed. Below the intermountane Alpine basins (Austria) and in the Southern Alpine Foreland (Italy) discoveries have been made at depths of up to 7 000 m (23 000′).
Project Financing for the Small Independent Company
Authors: Ramsay H. J. 
Published: December 2007

Abstract
This paper is written for the independent operator considering project financing in his operations. What the operator can expect in making these financial arrangements and how project financing compares to other financing methods is discussed.
Within the past decade, large amounts of capital have been needed by the petroleum industry to finance projects worldwide, especially in the North Sea area. In this area project financing has been used by companies having different objectives which include at least one of the following: raising capital, reducing financial exposure, or reducing capital costs1. In project financing the source of repayment is limited to the cash flow stream provided by a particular project. It can be used alone or in conjunction with other types of financing to provide a desired result relative to the corporate balance sheet and to the relative assumption of risks in the project between the borrower and the lender2,3.
Historically, financing for the small, independent company active in exploration and production involves oil production loans from commercial banks when the company has proved producing reserves to provide collateral for these loans. When such reserves are not available or the capital requirements outstrip the collateral value for conventional bank financing, the operator will resort to equity financing. Equity financing for the independent operator can include public and private limited partnerships, farmouts, and/or sale of a portion of the independent's interest at a promoted price. These types of equity financing are used by both public and private independent companies. Equity financing provides for spreading the risk and sharing the available capital within the industry, and also provides an important source of capital from outside the industry.
New Thoughts on an Old Topic: Reservoir Integration (Volumetrics)
Authors: Banks R. B. 
Published: December 2007

ABSTRACT
Although planimetering of contour maps to determine reservoir volumes is widely-accepted, it can be shown mathematically that planimetering always is less rigorous than numerical integration when integrating net volume, net porous volume or hydrocarbon pore volume. This is true whether a) individual variables (such as porosity and thickness) are contoured, planimetered and multiplied, or b) combined variables (such as porosity * thickness) are contoured and planimetered. Numerical integration is shown to be the most mathematically rigorous method of determining reservoir volumes.
The Log Analysis 8K ROM Module
Authors: Bateman R. M. , Hall F. D. , Beers T. W. 
Published: December 2007

ABSTRACT
Recent advances in computer technology have allowed ever larger computer circuits to occupy ever smaller physical dimensions. As a result, it is now possible to include a large body of detailed log analysis logic on a small Read-Only-Memory chip (ROM). The Log Analysis ROM, which weighs 7 grams and occupies less than 7 ccs, plugs into a widely used programmable pocket calculator. The Log Analyst is thus afforded easy access to a library of complex interpretation routines equivalent to those found heretofore only on mainframe computers.
This paper describes the evolution of the log analysis ROM from a technical viewpoint including the general procedure for building a ROM and then details the architecture of the log analysis routines available. Methods used to make the system "user friendly" are described including the plain english prompting for input, computation options, and formatting of outputs together with audible cues.
Suggestions are offered to the practical log analyst for both wellsite and office formation evaluation using the log analysis ROM and related calculator and peripherals. These include shaly sand analysis, complex lithology solutions, dip and bore hole geometry related transforms, cased hole evaluation, and many utilities such as solution resistivity and concentration conversions.
The paper is illustrated with examples of the application of the Log Analysis ROM to practical formation evaluation problems.
Why Rig Efficiencies have Decreased—Solutions
Authors: Kortlang W. F. 
Published: December 2007

Abstract
For the past five or six years, the drilling industry has experienced growth at a dramatic rate, beginning with the 1974–75 lease sales. During this period, contractors have increased the mobile rig fleet in the Gulf of Mexico by 116 percent, and have enjoyed 100 percent utilization. Although the rig population has exhibited this drastic rate of growth, an unexpected decline in the number of wells drilled has become evident, with the average number of wells decreasing from 8.23 wells per mobile rig to 3.8 wells per mobile rig. This behavior can be directly related to rig and/or drilling inefficiency. This paper will outline this phenomena, and will analyze it on the basis of the following criteria:
Relationship between rig production/operator expenditure/drilling efficiency. Causative factors attributable to decreasing rig efficiencies. Prospectus for the future concerning operator requirements with regard to contractor operations. Possible solutions to increase contractor and drilling efficiency.
Field Experience with PDC Bits in Northeast Texas
Authors: Arceneaux M. A. , Fielder J. L. 
Published: December 2007

Abstract
In an effort to improve penetration rates of infill drilling in northeast Texas, Sun Gas Division, Sun Exploration and Production initiated a program to evaluate the performance of polycrystalline diamond cutter (PDC) bits. Numerous bit runs were made in a selected interval in an attempt to determine which style PDC bit to use. Steel body and tungsten matrix body bits with various cutter configurations were evaluated. These bits were run under different parameters, i.e. weight on bit, rotary speed (RPM), hydraulics and mud type. Each bit run was reviewed, problems identified and corrective measures recommended for future runs. Results varied with the style PDC bit used. A cost per foot savings of 15% to 30% and a penetration rate increase of 45% to 75% were realized with the style PDC bit eventually selected when compared to rock bit drilling.
This paper will describe the style PDC bit, the geologic interval and the operating parameters under which the best performance was obtained. It is concluded that the use of these bits may be beneficial to other operators in this area and other areas of similar lithology.
Riser Collapse—A Unique Problem in Deep-Water Drilling
Authors: Erb P. R. , Ma Tien-Chi , Stockinger M. P. 
Published: December 2007

Abstract
While drilling an exploratory well in 1750 feet of water, a large kick emptied the marine riser. The two lowest joints collapsed due to the external pressure. A diverter failure also occurred. The equipment damage caused by this incident is described, and collapse calculations for the riser are presented. It is concluded that, if a kick is taken in deepwater after the subsea blowout preventers (BOPs) have been run, the subsea BOPs should be closed instead of activating the diverter, even if only shallow conductor casing is set. Diverter systems remain a must for shallow water operations, but their strength should be reevaluated and perhaps upgraded.
Cementing—Simultaneous Rotation—Reciprocating Technique (ROTO-TEK System)
Authors: Lee W. T. , Dorge W. D. 
Published: December 2007

Abstract
This paper presents an improved cementing technique which is called ROTO-TEK. This is a method of combining rotation and reciprocation of the casing string or liner during the cementing operation to give the best possible cement job. The design and application of the equipment is discussed giving the basic features of this equipment. The results of actual cementing jobs are discussed, showing the great improvement in cementing even in very difficult fields.
Development of Heavy Oil Reserves in South Oman
Authors: Nandyal Madhava , Thurber S. S. , Al-Hinai K. M. , Jaffer N. A. 
Published: December 2007

ABSTRACT
Significant discoveries of heavy oil accumulations (7+ billion barrels STOIIP) in South Oman have led to a greater emphasis on their development in the last 3-4 years. These fields are now being developed in a systematic manner keeping in mind the potential production problems and the practical use of enhanced oil recovery (EOR) techniques.
Most of the reserves occur in glacial to periglacial sandstones of Permo-carboniferous age which exhibit rapid facies variations. Geologic models developed from core data, drilling, seismic and petrophysical reviews, require continuous revision. Extensive appraisal drilling campaigns are in progress in the larger fields to define the reservoir limits and to delineate the observed rapid lateral variations in reservoir thickness, petrophysical characteristics and accumulation of oil. An integrated approach is followed in production planning and development. The high viscosity of the crude and unconsolidated nature of the formations create a typical sand production-problem environment. The occurrence of H2S in some fields and anticipation of early water production from both edge and bottom aquifers has necessitated cautious planning of facilities. Low solution-GOR and high crude viscosity preclude flowing production. Consequently, beam pumping is being installed in all fields. Most fields are planned for development on a square-grid pattern with varied well spacing which considers crude characteristics, reservoir properties and future EOR possibilities.
Since primary recoveries are expected to be low (5 to 15 percent), steps are being taken to initiate a pilot polymer flood and, at least, one pilot steam flood. Steam soak is also considered possible for the more viscous (&gt;1000 cP) reservoirs. Necessary basic reservoir data are being gathered for these projects and reservoir simulation process design studies are in progress. Facilities design and installation is also underway.
Considering the huge investments required for large-volume heavy oil production, phased development is planned in order to avoid a high production spike followed by a long period of declining production. Phased development will also allow a plateau production level as Oman's presently known lighter oil fields slowly decline.
Wellsite Gas Detection Helps in Controlling Abnormal Pressure and Picking Perforations on Development Wells
Authors: Struckel J. C. , Mercer R. F. 
Published: December 2007

ABSTRACT
Data obtainable with a low cost wellsite total gas detector can provide valuable assistance in production drilling. Gas liberated by the drill bit into the drilling mud is an effective tool for accurate perforation selection even if wireline log interpretation proves inconclusive. Gas produced into the mud system by the formation provides valuable assistance in detecting and monitoring abnormal pressure. Optimum mud weight can also be determined from produced gas data.
A Simplified Approach to Design of Fracturing Treatments Using High Viscosity Cross-Linked Fluids
Authors: McLeod H. O. 
Published: December 2007

ABSTRACT
Simple models are presented to evaluate or design hydraulic fracturing treatments using perfect transport fluids. The fracture geometry program calculates dimensions of a vertically contained fracture and the expected productivity ratio for the fractured well. A sand concentration program helps schedule sand to prevent sandouts and to ensure sufficient proppant at the wellbore.
High Efficiency Fracturing Fluids for High-Temperature, Low-Permeability Reservoirs
Authors: Baumgartner S. A. , Parker C. D. , Williams D. A. , Woodroof R. A. 
Published: December 2007

ABSTRACT
Reservoirs with permeabilities of less than 1 md and bottomhole temperatures in excess of 250°F are commonly encountered in the continuing search for hydrocarbons. Successful completion of these wells often requires the use of Massive Hydraulic Fracturing (MHF) treatments.
The fracturing fluids used in MHF treatments are frequently subjected to excessive shear and prolonged exposure at high bottomhole temperatures. Early fracturing fluids proved unsuitable for these MHF treatments due to a rapid loss of viscosity at high temperatures. As a result, narrow fracture widths, excessive fluid loss and poor proppant transport occurred. Cool-down pads, increased polymer concentrations and delayed polymer hydration systems were employed in an attempt to improve the MHF treatment success ratio.
A laboratory study was undertaken to develop a more efficient high temperature fracturing fluid. Rotational and pipe viscometers were used to evaluate thermal and shear stabilities under reservoir conditions. Fluid loss testing measured the effectiveness of fluid leakoff control. Fluid breakout testing ensured a controlled loss of viscosity and minimal proppant pack gel residue. As a result of this study, a more efficient high temperature fracturing fluid was developed.
This paper presents laboratory data comparing the thermal stability, shear stability and fluid loss control of the High Temperature Gel (HTG) with those of a conventional titanate crosslinked gel. Field case histories axe presented to demonstrate the efficiency with which the HTG system has been used to successfully stimulate low permeability gas wells with bottomhole temperatures in excess of 250°F.
Laboratory Simulations of Hydraulic Fracturing
Authors: Papadopoulos J. M. , Narendran V. M. , Cleary M. P. 
Published: December 2007

ABSTRACT
Two novel distinctly different laboratory apparatus have been developed to allow controlled, precise, repeatable and observable experimental simulations of hydraulic fracturing over a broad range of well-determined dominant parameters and practical geometries. One system avoids specimen preparation (by using predetermined interface separation), while the other most efficiently employs castable blocks with proper scaling of fracture toughness to correctly capture crack turning. These are based on a rigorous analysis of the physics and equations governing the hydrafrac process, which allow the extraction of the role played by each physical variable - so that these can be incorporated correctly in the scaling, e.g. from field operations to lab conditions. The experiments have already verified most of the primary features and results of the analysis: principal achievements include vindication of a characteristic time for the process, containing excess crack-opening pressure, material modulus and fluid rheology; general agreement with numerical results for actual growth rates of various fracture geometries; and verification of even more detailed predictions for evolution of cracks with mutual/tectonic interaction in various structural geometries and stress fields. Being perhaps the first stable, quasi-static and observable simulators, these apparatus promise to have a very broad range of applications in geophysics, resource extraction, structural analysis and geotechnical engineering.
Effect Of Stress Distribution On Hydraulic Fracture Geometry: A Laboratory Simulation Study In One Meter Cubic Blocks
Authors: Ahmed Usman , Strawn Jon , Wilson Michael , Schatz John 
Published: December 2007

ABSTRACT
The success of a hydraulic fracture treatment is greatly enhanced by control of the created fracture geometry. Of particular importance is the migration of the fracture into the boundary lithologies, which is largely determined by in- situ stress. Most of the presently used hydraulic fracturing models assume a constant fracture height confined to the pay zone, which predicts unrealistically large fracture lengths. Currently, a joint research program (involving The Gas Research Institute of Chicago, Chandler and Associates of Denver, and Terra Tek, Inc. of Salt Lake City) is underway that is evaluating, in the laboratory and in the field, several techniques to place (in conjunction with hydraulic fracturing) deeply penetrating fractures into pay formations not boundedby high stress barriers. Field work is taking place in the Douglas Creek Arch area of Colorado.
This paper presents a part of that program, the laboratory model study of hydraulic fracture propagation in one meter cubic blocks. The test block is loaded in a large frame which allows the independent application of minimum and maximum horizontal stressesto the simulated pay zone and two boundary lithologies, anda vertical stress to the entire block. The test block is internally strain gaged to allow the inference of the actual stress distribution both prior to, during, and after the fracture.Following hydraulic fracturing with a dyed fluid, the block is broken andthe created fracture surface area is examined. Through the use of this test set-up, the effect of in-situ stress on fracture geometry has been demonstrated, and a method of fracture geometry control basedon perforation placement has been established.
Use of Foaming Agents To Alleviate Liquid Loading in Greater Green River TFG Wells
Authors: Vosika J. L. 
Published: December 2007

ABSTRACT
Downtime and decreased production due to liquid accumulation in the wellbore are common problems among low volume tight formation gas wells. Recently, foaming agent injection was initiated in several Greater Green River Basin area wells as a low cost method to combat liquid loading problems.
This paper illustrates that the use of foaming agents has proven to be an inexpensive yet effective solution to liquid loading problems in area gas wells.