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Electromagnetic methods for development and production: State of the art

Description: Electromagnetic (EM) methods, long used for borehole logging as a formation evaluation tool in developed oil fields, are rarely applied in surface or crosshole configurations or applied in cased wells. This is largely due to the high levels of cultural noise and the preponderance of steel well casing. However, recent experimental success with crosshole EM systems for water and steam flood monitoring using fiberglass cased wells has shown promise in applying these techniques to development and production (D & P) problems. This paper describes technological solutions that will allow for successful application of EM techniques in oil fields, despite surface noise and steel casing. First an example sites the application of long offset logging to map resistivity structure away from the borehole. Next, a successful application of crosshole EM where one of the wells is steel cased is described. The potential application of earth`s field nuclear magnetic resonance (NMR) to map fluid saturation at large distances from the boreholes is also discussed.
Date: October 1, 1997
Creator: Wilt, M. & Alumbaugh, D.
Partner: UNT Libraries Government Documents Department

Precision pressure/temperature logging tool

Description: Past memory logging tools have provided excellent pressure/temperature data when used in a geothermal environment, and they are easier to maintain and deploy than tools requiring an electric wireline connection to the surface. However, they are deficient since the tool operator is unaware of downhole conditions that could require changes in the logging program. Tools that make ``decisions`` based on preprogrammed scenarios can partially overcome this difficulty, and a suite of such memory tools has been developed at Sandia National Laboratories. The first tool, which forms the basis for future instruments, measures pressure and temperature. Design considerations include a minimization of cost while insuring quality data, size compatibility with diamond-cored holes, operation in holes to 425 C (800 F), transportability by ordinary passenger air service, and ease of operation. This report documents the development and construction of the pressure/temperature tool. It includes: (1) description of the major components; (2) calibration; (3) typical logging scenario; (4) tool data examples; and (5) conclusions. The mechanical and electrical drawings, along with the tool`s software, will be furnished upon request.
Date: January 1, 1998
Creator: Henfling, J.A. & Normann, R.A.
Partner: UNT Libraries Government Documents Department

North-South Cross Section, Pumpkin Buttes, Wyoming

Description: This map shows geologic formations of sandstone, shale, siltstone, mudstone, and coal, carbonaceous markers, coal seams, creeks and rivers, draws and gulches, mountains, buttes, and numbered locations of uranium test holes.
Date: January 1973
Creator: McKeel, B. K.; Love, J. D. & Crew, M. E.
Partner: UNT Libraries Government Documents Department

Coal Draw Cross Section, Powder River Basin, Wyoming

Description: This map shows geologic formations of sandstone, shale, siltstone, mudstone, and coal, carbonaceous markers, coal seams, creeks and rivers, draws and gulches, mountains, buttes, and numbered locations of uranium test holes.
Date: December 1972
Creator: McKeel, B. K.; Love, J. D. & Crew, M. E.
Partner: UNT Libraries Government Documents Department

Final report. Electro-Seise, Inc., Airborne Survey

Description: The Rocky Mountain Oilfield Testing Center (RMOTC) has recently completed a test of an airborne microgravity and electric field sensing technology developed by Electro-Seise, Inc. of Fort Worth, Texas. The test involved the use of a single engine airplane to gather data over the Teapot Dome oil field along a tight grid spacing and along thirty (30) survey lines. The resultant gravity structure maps, based on the field data, were found to overlay the known structure of Teapot Dome. In addition, fault maps, based on the field data, were consistent with the known fault strike at Teapot Dome. Projected hydrocarbon thickness maps corresponded to some of the known production histories at RMOTC. Exceptions to the hydrocarbon thickness maps were also found to be true.
Date: June 1, 2001
Creator: Schulte, Ralph
Partner: UNT Libraries Government Documents Department

Formation evaluation in liquid-dominated geothermal reservoirs

Description: Studies relative to some formation evaluation aspects of geothermal reservoirs are reported. The particular reservoirs considered were the liquid dominated type with a lithology of the sedimentary nature. Specific problems of interest included the resistivity behavior of brines and rocks at elevated temperatures and studies on the feasibility of using the well log resistivity data to obtain estimates of reservoir permeability. Several papers summarizing the results of these studies were presented at various technical meetings for rapid dissemination of the results to potential users. These papers together with a summary of data most recently generated are included. A brief review of the research findings precedes the technical papers. Separate abstracts were prepared for four papers. Five papers were abstracted previously for EDB.
Date: April 1, 1981
Creator: Ershaghi, I.; Dougherty, E.E. & Handy, L.L.
Partner: UNT Libraries Government Documents Department

FORTRAN algorithm for correcting normal resistivity logs for borehold diameter and mud resistivity

Description: The FORTRAN algorithm described was developed for applying corrections to normal resistivity logs of any electrode spacing for the effects of drilling mud of known resistivity in boreholes of variable diameter. The corrections are based on Schlumberger departure curves that are applicable to normal logs made with a standard Schlumberger electric logging probe with an electrode diameter of 8.5 cm (3.35 in). The FORTRAN algorithm has been generalized to accommodate logs made with other probes with different electrode diameters. Two simplifying assumptions used by Schlumberger in developing the departure curves also apply to the algorithm: (1) bed thickness is assumed to be infinite (at least 10 times larger than the electrode spacing), and (2) invasion of drilling mud into the formation is assumed to be negligible.
Date: unknown
Creator: Scott, J.H.
Partner: UNT Libraries Government Documents Department

Numerical modeling and interpretation of dipole-dipole resistivity and IP profiles Cove Fort-Sulphurdale KGRA, Utah

Description: The Cove Fort-Sulphurdale Known Geothermal Resource Area (KGRA) is located near the junction of the Pavant Range and the Tushar Mountains in south-central Utah. The area has been the site of an intensive geothermal exploration effort since 1975. The electrical resistivity data obtained by Union Oil Company and a subsequent survey conducted for the Earth Science Laboratory and a detailed numerical interpretation of both data sets are presented. The detailed modeling permits a characterization of the intrinsic electrical resistivity to depths exceeding 2000 feet. An area of over two square miles with bulk in-situ resistivities of four-to-five ohm-m is delineated at Sulphurdale near the Union Oil Co. well CFSU No. 42-7. The low-resistivities rocks define the area of extensive hydrothermal alteration in response to the presence of clay minerals and conductive thermal fluids. In contrast the area north and east of Cove Fort is typified by high (100-300 ohm-m) resistivities to depths exceeding 2000 feet. This is an area of Cretaceous and Paleozoic sedimentary rocks where two attempts to drill to reservoir depth failed because of extreme drilling problems. The high resistivities are not considered encouraging for the presence of a deeper reservoir. The electrical resistivity interpretation has defined several areas of probable upward migration of thermal fluids along north-trending normal faults. Some of these areas may have potential for direct heat geothermal utilization.
Date: December 1, 1979
Creator: Ross, H. P.
Partner: UNT Libraries Government Documents Department

Magnetic induction technique for mapping vertical conductive fractures: status report

Description: Fracture mapping plays a vital role in the production of energy from hot dry rock. Many fracture mapping techniques are summarized, and their merits discussed. Of these methods, one based on magnetic induction appears to be well suited for the hot dry rock application. As of August 1977, the status is given here of the development of a fracture mapping instrument using magnetic induction. The basic analysis and electronic design have been completed. Detailed mechanical design and fabrication remain.
Date: December 1, 1977
Creator: Landt, J.A.; Rowley, J.C.; Neudecker, J.W. & Koelle, A.R.
Partner: UNT Libraries Government Documents Department

Geophysical well logging operations and log analysis in Geothermal Well Desert Peak No. B-23-1

Description: Geothermal Well Desert Peak No. B-23-1 was logged by Dresser Atlas during April/May 1979 to a total depth of 2939 m (9642 ft). A temperature of 209/sup 0/C (408/sup 0/F) was observed on the maximum thermometer run with one of the logging tools. Borehole tools rated to a maximum temperature of 204.4/sup 0/C (400/sup 0/F) were utilized for logging except for the Densilog tool, which was from the other set of borehole instruments, rated to a still higher temperature, i.e., 260/sup 0/C (500/sup 0/F). The quality of the logs recorded and the environmental effects on the log response have been considered. The log response in the unusual lithologies of igneous and metamorphic formations encountered in this well could be correlated with the drill cutting data. An empirical, statistical log interpretation approach has made it possible to obtain meaningful information on the rocks penetrated. Various crossplots/histograms of the corrected log data have been generated on the computer. These are found to provide good resolution between the lithological units in the rock sequence. The crossplotting techniques and the statistical approach were combined with the drill cutting descriptions in order to arrive at the lithological characteristics. The results of log analysis and recommendations for logging of future wells have been included.
Date: March 1, 1980
Creator: Sethi, D.K. & Fertl, W.H.
Partner: UNT Libraries Government Documents Department

Cross-borehole and surface-to-borehole electromagnetic induction for reservoir characterization

Description: Audio-frequency cross-borehole and surface-to-borehole electromagnetics (EM) are interesting alternatives to existing techniques for petroleum reservoir characterization and monitoring. With these methods signals may be propagated several hundreds of meters through typical sand/shale reservoirs and data may be collected at high accuracy with a high sensitivity to the subsurface resistivity distribution. Field systems for cross-borehole and surface-to-borehole EM measurements have been designed and built by Lawrence Livermore and Lawrence Berkeley Laboratories for reservoir evaluation and monitoring. The cross-borehole system utilizes vertical axis induction coil antennas for transmission and detection of sinusoidal signals. Data are collected in profiles with the source coil moving continuously while its signal is detected by a stationary receiver coil located in a separate well. Subsequent profiles are collected using a different receiver depth and the same transmitter span until a suite of profiles is obtained that cover the desired interval in the borehole. The surface-to-borehole system uses a large diameter surface loop transmitter and a vertical axis borehole receiver. Due to its high signal strength this system operates using a sweep frequency transmitter waveform so that data may be simultaneously collected over several decades of frequency. Surface-to-borehole profiles are equally repeatable and although this data is less sensitive than cross-borehole EM, it can be fit to a resistivity section consistent with the borehole log. 8 refs., 14 figs.
Date: August 1, 1991
Creator: Wilt, M.J.; Morrison, H.F.; Becker, A. & Lee, K.H.
Partner: UNT Libraries Government Documents Department

New Mexico State University geothermal production well. Technical completion report, January 1, 1978-December 31, 1979

Description: The detailed technical specifications for the production well, the lithologic sample analysis, and a suite of geophysical logs, consisting of electrical resistivity, spontaneous potential, gamma ray and neutron, are presented. (MHR)
Date: January 1, 1981
Creator: Chaturvedi, L.
Partner: UNT Libraries Government Documents Department

Western Gas Sands Project: Northern Great Plains Province review

Description: The synopsis outlines the Upper Cretaceous low permeability natural (biogenic) gas formations of the Northern Great Plains Province (NGPP) of Montana, Wyoming, North and South Dakota. The main objectives are to present a general picture of that stratigraphy, significant structures, and natural gas potential.
Date: August 1, 1979
Creator: Newman, III, H E
Partner: UNT Libraries Government Documents Department

Induced-polarization measurements at Roosevelt Hot Springs Thermal area, Utah

Description: An induced polarization survey was conducted at Roosevelt Hot Springs, using the dipole-dipole array. The survey consisted of two profile lines, one across the southern end of the system (2200N) and another across the northern portion (5950N). A total of 15 line-km of profiles was run, with 100 m and 300 m dipoles out to n spacings of 4 to 6. Apparent resistivity amplitude and phase data were gathered with a phase-sensitive receiver at frequencies between 32 Hz and 1/256 Hz. The data are presented in the form of apparent resistivity of phase pseudosections. Induced polarization effects in geothermal environments can result from clays and pyrite which are associated with hydrothermal alteration. Laboratory measurements on altered material show some induced polarization effects at frequencies below 1 Hz which are thought to be due to pyrite. A higher frequency polarization (> 1 Hz) is attributed to the effects of clays. The primary purpose of this survey was to investigate the feasibility of mapping clay alteration zones, and separating them from other conductive features, by making use of their polarization characteristics. The field data show some small, low frequency phase anomalies which may be the result of pyrite deposition. The higher frequencies show considerable phase effects, which can be the result of clays, but the effects of electromagnetic coupling have not, as yet, been assessed.
Date: June 1, 1979
Creator: Chu, J.J.; Sill, W.R. & Ward, S.H.
Partner: UNT Libraries Government Documents Department

Natural-gas-hydrate deposits: a review of in-situ properties

Description: The Los Alamos hydrate project has concentrated on: evaluating techniques to produce gas from hydrate deposits to determine critical reservoir and production variables; predicting physical properties of hydrate-containing sediments both for their effects on production models and to allow us to develop geophysical exploration and reservoir characterization techniques; and measuring properties of synthetic hydrate cores in the laboratory. Exploration techniques can help assess the size of potential hydrate deposits and determine which production techniques are appropriate for particular deposits. So little is known about the physical properties of hydrate deposits that it is difficult to develop geophysical techniques to locate or characterize them; but, because of the strong similarity between hydrates and ice, empirical relationships between ice composition and seismic velocity, electrical resistivity, density, and heat capacity that have been established for frozen rocks may be used to estimate the physical properties of hydrate deposits. Resistivities of laboratory permafrost samples are shown to follow a variation of Archie's equation. Both the resistivities and seismic velocities are functions of the unfrozen water content (Sw); however, resistivities are more sensitive to changes in Sw, varying by as much as three orders of magnitude, which may allow the use of electrical resistivity measurements to estimte the amount of hydrate in place. We estimated Sw, assuming that the dissolved salt in the pore water is concentrated as a brine phase as the hydrates form, and the brine content as a function of depth, assuming several temperature gradients and pore water salinities. Hydrate-bearing zones are characterized by high seismic velocities and electrical resistivities compared to unfrozen sediments or permafrost zones.
Date: January 1, 1982
Creator: Halleck, P.M.; Pearson, C.; McGuire, P.L.; Hermes, R. & Mathews, M.
Partner: UNT Libraries Government Documents Department