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Geoscience/Engineering Characterization of the Interwell Environment in Carbonate Reservoirs Based on Outcrop Analogs, Permian Basin, West Texas and New Mexico.

Description: The objective of this project is to investigate styles of reservoir heterogeneity found in low permeability pelleted wackestone/packstone facies and mixed carbonate/clastic facies found in Permian Basin reservoirs by studying similar facies exposed in the Guadalupe Mountains. Specific objectives for the outcrop study include construction of a stratigraphic framework, petrophysical quantification of the framework, and testing the outcrop reservoir model for effects of reservoir heterogeneity on production performance. Specific objectives for the subsurface study parallel objectives for the outcrop study.
Date: December 31, 1996
Creator: Lucia, F.J. & Kerans, C.
Partner: UNT Libraries Government Documents Department

Geobotanical Remote Sensing Applied to Targeting New Geothermal Resource Locations in the U.S. Basin and Range with a Focus on Dixie Meadows, NV

Description: This paper presents an overview of the work our collaboration is doing to increase the detailed mapped resource base for geothermal exploration in the Western US. We are imaging several large areas in the western US with high resolution airborne hyperspectral and satellite multispectral sensors. We have now entered the phase where the remote sensing techniques and tools we are developing are mature enough to be combined with other geothermal exploration techniques such as aeromagnetic, seismic, well logging and coring data. The imaging sensors and analysis techniques we have developed have the ability to map visible faults, surface effluents, altered minerals, subtle hidden faults. Large regions are being imaged at reasonable costs. The technique of geobotanical remote sensing for geothermal signatures is based on recent successes in mapping hidden faults, high temperature altered mineralization, clays, hot and cold springs and CO2 effluents the Long Valley Caldera and Mammoth Mountain in California. The areas that have been imaged include Mammoth Mountain and the Long Valley Caldera, Dixie Meadows NV, Fish Lake Valley NV, and Brady Hot Springs. Areas that are being imaged in the summer of 2003 are the south moat of the Long Valley Caldera, Mammoth Mountain western Pickles, Nash, Kasameyer, Foxall, Martini, Cocks, Kennedy-Bowdoin, McKnight, Silver, Potts, flanks, Mono Inyo chain north of Mammoth Mountain in CA, and the Humboldt Block in NV. This paper focuses on presenting the overview of the high-resolution airborne hyperspectral image acquisition that was done at Dixie Meadows NV in August 2002. This new imagery is currently being analyzed and combined with other field data by all of the authors on this paper. Results of their work up until the time of the conference will be presented in papers in the remote sensing session.
Date: January 1, 2003
Creator: Pickles, W. L.; Nash, G. D.; Calvin, W. M.; Martini, B. A.; Cocks, P. A.; Kenedy-Bowdoin, T. et al.
Partner: UNT Libraries Government Documents Department

Changes of Well Characteristics in the Hatchobaru Geothermal Field (Japan) by Exploitation of Unit No. 2

Description: The reservoir exploitation for Unit No.2 of the Hatchobaru Power Station accelerated the decline of power output of Unit No.1. For the purpose of understanding the mechanism of this output decline, review of existing data, additional well characteristics tests, well loggings and tracer tests were carried out. The results showed that several production wells for Unit No. 1 significantly reduced their productivity due to the inflow of reinjected waste water and due to pressure interference with production wells for Unit No. 2.
Date: January 1, 1995
Creator: Mimura, T.; Oishi, K.; Ogata, Y.; Tokita, H.; Tsuru, Y. & Matsuda, K.
Partner: UNT Libraries Government Documents Department

Calibration of a neutron log in partially saturated media IV: effects of sonde-wall gap

Description: A gap between a neutron sonde and the wall of a borehole can have a significant effect on the observed count rate. This effect was determined experimentally to be linear with gaps as large as 2.5 cm. The count rate is given by N/sub N/ = K/sub 0/ + K/sub 1/g where K/sub 0/ is the count rate that would be observed at zero gap, and g is the gap. The parameters K/sub 0/ and K/sub 1/ are dependent on both water (ie. hydrogen) content and bulk density. In many situations failure to correct the count rate for this gap effect can result in a significant degradation in the accuracy of the water content calculated from the count rate. In a dry borehole, K/sub 1/ is small at zero formation water content, and increases with formation water content. In a water-filled borehole, K/sub 1/ is large at zero formation water content, and tends to decrease with increasing formation water content, becoming zero, as of course it must, if the formation is pure water. The absolute value of K/sub 1/ increases with increasing density. A representation was determined for K/sub 0/ and K/sub 1/ from experimental data. This representation can be used to adjust the count rate at a given gap to equal its zero-gap value. The accuracy of the zero gap equation can then be recovered.
Date: March 8, 1984
Creator: Axelrod, M.C. & Hearst, J.R.
Partner: UNT Libraries Government Documents Department

Geothermal resources Frio Formation, South Texas

Description: A preliminary study of the Frio sand distribution and formation temperatures and pressures was undertaken in order to define prospective areas in which a more detailed reservoir analysis is necessary prior to the selection of a site for a geothermal well. As a result two potential geothermal fairways were identified--one in the south part of the area in Hidalgo, Willacy, and Cameron Counties, and the other in the north part in north-central Nueces County.
Date: January 1, 1975
Creator: Bebout, D.G.; Dorfman, M.H. & Agagu, O.K.
Partner: UNT Libraries Government Documents Department

Heat flow and sub-surface temperatures in the Great Valley, California

Description: The Great Valley of California is located between the Coastal Ranges and the Sierra Nevada and geologically is a structural trough with a thick sequence of sediments. Preliminary investigations of heat flow indicates that this region is characterized by a low-to-normal heat flow of 0.6 to 1.3 HFU. A number of shallow holes for water supply and deep holes for oil and gas exploration have been drilled. Temperature measurements were made in most of these holes. Unfortunately, core and drill cuttings were available from only a few holes for thermal conductivity measurements. Here, three new heat-flow values, a gradient map, and an isotherm map of temperatures at 200 meters are presented.
Date: January 1, 1982
Creator: Wang, J. & Munroe, R.J.
Partner: UNT Libraries Government Documents Department

Hot dry rock heat mining: An advanced geothermal energy technology

Description: The conventional geothermal industry relies on naturally occurring fluids, either liquids or gases to transport the internal heat of the earth to the surface where it is applied to useful purposes, but there are only a relatively few places where these hydrothermal resources exist at temperatures high enough to generate electric power. Over most of the world, the hot rock beneath the surface is relatively dry. Geothermal energy in the form of hot dry rock (HDR) is abundant, widely distributed, and accessible. Energy extraction from HDR promises to be economically competitive and can be accomplished with essentially no adverse environmental effects. The purpose of this paper is to describe the technology which is being developed to gain access to, mine, and utilize the thermal energy existing in HDR. For the last two decades, the Los Alamos National Laboratory has been working to develop techniques for mining HDR energy. Early worked proved that it is feasible to extract thermal energy using drilling and fracturing techniques adapted from the petroleum and geothermal industries. Recently, results have demonstrated that it should be possible to operate HDR plants in a closed-loop mode with minimal water use. Long-term testing is about to begin at the HDR facility operated by Los Alamos at Fenton Hill in the Mountains of northern New Mexico. The goal of this test will be to demonstrate that useful amounts of energy can be produced from HDR on a sustainable basis. Results of this work will form the basis for design, construction, and operation of economic HDR plants in the future. Significant HDR programs are now underway in a number of countries. As the technology matures, HDR should take its place as a clean, economically competitive energy source for the world. 11 refs., 7 figs., 2 tabs.
Date: January 1, 1991
Creator: Duchane, D.V.
Partner: UNT Libraries Government Documents Department

Downhole electrical detection of hydraulic fractures in GT-2 and EE-1

Description: Electrical geophysical methods including mise a la masse and self-potential (SP) for determination of hydraulic fracture characteristics were used at the hot dry rock geothermal project. Electrical and induction logs indicated that the resistivity contrast between the granite and 200/sup 0/C water at the 2926-m (9600-ft) depth is a factor of 1000 or more. Thus the water in a hydraulic fracture, formed to connect two adjacent deep holes, is a good conductor compared to the confining granite. Mise a la masse-type measurements were made to help determine the characteristics for hydraulic fractures formed in each of the two geothermal holes GT-2 and EE-1. Once a hydraulic fracture has been formed, mise a la masse effects are obtained both with the fracture pressurized above hydrostatic and when depressurized to hydrostatic. This indicates that once the fracture has been created, enough natural propping exists that a conductive zone persists even when the fracture is deflated. A fracture was formed in a 18-m (60-ft) zone immediately below 1957 m (6420 ft) in EE-1. Later a set of SP logs was run in this zone with no pressure, with pressure building, with pressure decreasing, and again with the fracture depressurized. Results show that during times of change of parameters in hydraulically fractured regions in the hole, natural SP logging helps to determine the position of the fracture. However, after a fracture has come to equilibrium with fluid parameters such as temperature, pressure, salinity, and pH, an effect of the fracture may not be evident. Self-potential logs provide an excellent method for locating the bottom of steel casing that has been set in the hole.
Date: July 1, 1977
Creator: Kintzinger, P.R.; West, F.G. & Aamodt, R.L.
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

Heat-flow reconnaissance of the Gulf Coastal Plain

Description: Most of the 46 new values of heat flow determined for the Gulf Coastal Plain are in the low to normal range, but heat-flow values averaging 1.8 heat-flow unit (HFU) were obtained in Claiborne, Ouachita, and Union parishes, Louisiana. Moreover, a zone of relatively high heat-flow values and steep thermal gradients (35 to 46/sup 0/C/km) extends from northern Louisiana into southwestern Mississippi. Also near Pensacola, Florida, temperatures of 50/sup 0/C at 1-km depth have been extrapolated from thermal gradients. Future development of low-grade geothermal resources may be warranted in these areas.
Date: April 1, 1982
Creator: Smith, D.L. & Shannon, S.S. Jr.
Partner: UNT Libraries Government Documents Department

Geothermal down-well instrumentation (during drilling). Final report

Description: The object of the work was to investigate acoustic and electromagnetic telemetry methods which could be used as a basis for geothermal MWD systems. The emphasis has been on methods which employ the drill string and/or the formation surrounding the borehole as a signalling media. The investigations have been confined to the transmission characteristics of these media and have excluded the area of downwell measurements. Work performed includes: laboratory measurement of acoustic attenuation in drill pipe; field measurement of acoustic attenuation in drill pipe; measurements of drill string vibrations (drilling noise) during drilling; evaluation of drill string vibration dampers; modeling of electromagnetic propagation in the borehole region; and field measurements of attenuation of a downwell electromagnetic signal source. (MHR)
Date: June 1, 1979
Creator: Kent, W.H.; Mitchell, P.G. & Row, R.V.
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

Fabrication of a 275/sup 0/C geothermal temperature tool

Description: The fabrication of a Prototype 275/sup 0/C Geothermal Temperature Tool is reviewed. This tool fabrication uses hybrid circuits that were developed at Sandia National Laboratories and are now being built at Teledyne Philbrick. To achieve high-temperature operation, the standard military specification hybrid technology was modified in fabrication processes and materials.
Date: January 1, 1981
Creator: Bonn, P.A.
Partner: UNT Libraries Government Documents Department

The US Hot Dry Rock Geothermal Energy Development Program

Description: Recent accomplishments of the program are highlighted by a successful limited term flow test of the Phase 2 reservoir at the Fenton Hill site near Los Alamos. This reservoir connection was established by sidetracking one of the deep wells into hydraulically fractured areas, identified by microseismic data after original fracture attempts failed to connect the two wells. Hydraulic communication was improved by supplemental fracturing. Preliminary testing indicated a reservoir with fracture volume and heat production area surpassing the values from the earlier Phase 1 reservoir. Following completion of the downhole reservoir system, preparations were made for a reservoir-energy-extraction test. This Initial Closed Loop Flow Test (ICFT) was needed to obtain operating characteristics for planning a much longer test for thorough reservoir evaluation. The 30-day ICFT succeeded with final production of about 10 MWt at 192/sup 0/C, while injecting 285 gpm at 4600 psi and producing 206 gpm at 500 psi. The water loss rate and flow impedance were high, 27% and 18 psi/gpm respectively, but were declining. Radioactive tracer tests indicated reservoir volume growth during the experiment which was continuously monitored for acoustic or microseismic activity. Following the flow test, experiments were continued for several months during the venting process. Preparations are now underway for the Long Term Flow Test (LTFT). To understand as much as possible about the Phase 2 reservoir and to demonstrate the commercial feasibility of energy from HDR reservoirs, a flow test of approximately one year's duration is deemed necessary. Part of the preparation for the LTFT is the workover and repair of the production well and the installation of a competent overall flow loop and energy exchange system. 7 refs., 5 figs.
Date: January 1, 1987
Creator: Franke, P.R.
Partner: UNT Libraries Government Documents Department

Structural and sedimentological study of the Cerro Prieto geothermal field, Baja California, Mexico

Description: Geophysical and lithologic well logs from over fifty wells have been qualitatively and quantitatively analyzed using both manual and computer interpretation techniques. These logs were studied to make stratigraphic correlations throughout the Cerro Prieto field and to interpret the deltaic depositional environment of the field's lithologic units. Dipmeter and seismic data were of great value in making stratigraphic interpretations and extrapolations. Cross sections were constructed to illustrate lithofacies variations throughout the geothermal field. In turn, these sections were used to construct a three-dimensional model of the Cerro Prieto geothermal reservoir. Petrographic microscopy, scanning electron microscopy, and x-ray diffraction analyses of well-bore cuttings and cores were utilized to determine the degree and distribution of hydrothermal alteration by fluids at temperatures up to 350{sup 0}C, the origins of dissolution porosity, and the relative degree of fracture versus dissolution porosity. The results of these analyses were confirmed by log-derived determinations of formation fluid properties, porosity, and petrophysical properties and by studies of Cerro Prieto cores conducted under in-situ conditions. The results of this research were integrated into the Cerro Prieto reservoir model.
Date: June 1, 1981
Creator: Vonder Haar, S.
Partner: UNT Libraries Government Documents Department

Shallow subsurface temperatures and some estimates of heat flow from the Colorado Plateau of northeastern Arizona

Description: Temperature data to depths of a few hundred meters were obtained from 29 wells in northeastern Arizona; 12 in the region surrounding the San Francisco Volcanic Field, 8 in the Black Mesa area, and 9 in the south-central Colorado Plateau which includes the White Mountains. Although there was evidence for local hydrologic disturbances in many temperature profiles, most wells provided an estimate of the conductive thermal gradient at the site. A few thermal conductivities were measured and were combined with published regional averages for the north-central part of the Colorado Plateau to produce crude estimates of regional heat flux. None of the wells was accessible below the regional aquifers. To these depths, heat flow in the area of the San Francisco Volcanic Field appears to be controlled primarily by regional lateral water movement having a significant downward vertical component of velocity. The mean heat flow of 27 +- 5 mWm/sup -2/ is only a third to a quarter of what we would expect in this tectonic setting. The heat that is being carried laterally and downward probably is being discharged at low enthalpy and low elevation in springs and streams of the Colorado Plateau and Mogollon Rim. In the vicinity of Black Mesa, heat-flow averages about 60 mWm/sup -2/, characteristics of the coal interior of the Colorado Plateau. North of the White Mountain Volcanic Field, the average heat flow is about 95 mWm/sup -2/.
Date: January 1, 1982
Creator: Sass, J.H.; Stone, C. & Bills, D.J.
Partner: UNT Libraries Government Documents Department

Borehole survey instrumentation development for geothermal applications

Description: The creation and subsequent study of hot dry rock geothermal reservoirs requires sophisticated tools and instruments that can function for relatively long periods of time in the hostile downhole environment. Detection of fracture dimensions and orientation of the geothermal reservoir is critical for the successful completion of the hot dry rock energy extraction system. The development of downhole instrumentation capable of characterizing the hydraulic-fracture systems must emphasize reliability of measuring devices and electro-mechanical components to function properly at borehole temperature exceeding 275/sup 0/C and pressures of 69 MPa (10,000 psi).
Date: January 1, 1980
Creator: Dennis, B.R.
Partner: UNT Libraries Government Documents Department

High temperature testing of the EDCON borehole gravity housing system conducted at Los Alamos National Laboratories, January 12-18, 1986

Description: A series of tests were conducted on the EDCON borehole gravity meter (BHGM) high temperature sonde. The tests were conducted to determine the suitability of this sonde for logging operations in the Department of Energy Salton Trough test well. 1 ref., 3 figs., 4 tabs.
Date: January 1, 1986
Partner: UNT Libraries Government Documents Department

FY 79 Lava Lake Drilling Program: results of drilling experiments

Description: A drilling program was conducted in December 1978 and January and February 1979 to continue the characterization of the solid and liquid rock components of the Kilauea Iki lava lake. Six holes were drilled from the surface and two previously drilled holes were reentered and deepened for the purposes of measuring downhole temperature profiles, recovering samples of solid, plastic, and molten rock, measuring crust permeability, and determining the performance of conventional and special drilling techniques. Conventional HQ-size (3.78 inches diameter) core drilling equipment using water for cooling and cuttings removal was used to successfully drill during initial entry into 1052/sup 0/C formations. Conventional drilling in reentering flow-back rock was less reliable. The specially designed water jet-augmented drag bit or water jet-augmented core bit was needed to drill reliably into the plastic flow-back rock and through liquid rock veins. This document contains the drill performance data which were recorded during drilling in the crust and the plastic and molten rock zones using both conventional and special drilling procedures and equipment.
Date: December 1, 1979
Creator: Neel, R.R.; Striker, R.P. & Curlee, R.M.
Partner: UNT Libraries Government Documents Department

Sandstone consolidation analysis to delineate areas of high-quality reservoirs suitable for production of geopressured geothermal energy along the Texas Gulf Coast

Description: Analysis of reservoir quality of lower Tertiary sandstones along the Texas Gulf Coast delineates areas most favorable for geopressured geothermal exploration. Reservoir quality is determined by whole core, acoustic log, and petrographic analyses. The Wilcox Group has good reservoir potential for geopressured geothermal energy in the Middle Texas Gulf Coast and possibly in adjacent areas, but other Wilcox areas are marginal. The Vicksburg Formation in the Lower Texas Gulf Coast is not prospective. Reservoir quality in the Frio Formation increases from very poor in lowermost Texas, to marginal into the Middle Texas Gulf Coast and to good through the Upper Texas Gulf Coast. The Frio Formation in the Upper Texas Gulf Coast has the best deep-reservoir quality of any unit along the Texas Gulf Coast. (MHR)
Date: January 1, 1979
Creator: Loucks, R.G.; Dodge, M.M. & Galloway, W.E.
Partner: UNT Libraries Government Documents Department

United States Gulf Coast geopressured-geothermal program. Annual report, 1 November 1980-31 October 1981

Description: The following are included: objectives, overview, coordination assistance, compaction measurements on Texas Gulf Coast Sandstones and Shales; US Gulf Coast Geopressured-Geothermal Aquifer simulation, Preliminary Review of Subsidence Insurance Issues, Geopressured-Geothermal Information System, and Study of Log Derived Water Resistivity Values in Geopressured Geothermal Formations. (MHR)
Date: July 1, 1982
Creator: Dorfman, M.H.; Morton, R.A.; Dunlap, H.F.; Frederick, D.O.; Gray, K.E.; Peters, E.J. et al.
Partner: UNT Libraries Government Documents Department

Depositional setting, structural style, and sandstone distribution in three geopressured geothermal areas, Texas Gulf Coast

Description: Three areas in the Texas Gulf Coastal Plain were studied using electric logs and seismic-reflection data to interpret their depositional and structural history and to compare their potential as geopressured-geothermal reservoirs. The Cuero study area, on the lower Wilcox (upper Paleocene) growth-fault trend, is characterized by closely and evenly spaced, subparallel, down-to-the-basin growth faults, relatively small expansion ratios, and minor block rotation. Distributary-channel sandstones in the geopressured lower Wilcox Group of the South Cook fault block appear to be the best geothermal aquifers in the Cuero area. The Blessing study area, on the lower Frio (Oligocene) growth-fault trend, shows wider and more variable fault spacing and much greater expansion ratios and block rotation, particularly during early Frio time. Thick geopressured sandstone aquifers are laterally more extensive in the Blessing area than in the Cuero area. The Pleasant Bayou study area, like the Blessing area, is on the Frio growth-fault trand, and its early structural development was similar rapid movement of widely spaced faults resulted in large expansion ratios and major block rotation. However, a late-stage pattern of salt uplift and withdrawal complicated the structural style. Thick geopressured lower Frio sandstone aquifers are highly permeable and laterally extensive, as in the Blessing area. In all three areas, geopressured aquifers were created where early, rapid movement along down-to-the-basin growth faults juxtaposed shallow-water sands against older shales, probably deposited in slope environments. Major transgressions followed the deposition of reservoir sands and probably also influenced the hydraulic isolation that allowed the build up of abnormal pressures. 26 refs., 49 figs., 8 tabs.
Date: January 1, 1983
Creator: Winker, C.D.; Morton, R.A.; Ewing, T.E. & Garcia, D.D.
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

Radioactive tracers used to characterize geothermal reservoirs

Description: Data obtained from Br/sup 82/ tracer injections with downhole gamma ray monitoring were used to quantify flow fractions entering and leaving the GT-2B and EE-1 reservoirs at various depths. The Br/sup 82/ tracer method also provided data needed to characterize changes in the reservoir volume and flow distribution within fracture system during the recent 281 day sustained heat extraction experiment at the Hot Dry Rock Fenton Hill Site.
Date: January 1, 1981
Creator: Dennis, B.R.; Potter, R. & Kolar, J.
Partner: UNT Libraries Government Documents Department