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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

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

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

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

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

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

Study effects of geopressured-geothermal subsurface environment on elastic properties of Texas Gulf Coast sandstones and shales using well logs, core data, and velocity surveys. Final report

Description: Relations between porosity and permeability for the Pleasant Bayou wells were determined from conventional core data. Porosities from the time average equations required compaction correction factors of 1.9 in hydropressured sandstones and 1.0 in geopressured sandstones. Best average prmeabilities in the geopressured zone were found in the primary production interval 14,687 to 14,716 ft (4477 to 4485 m). Average density gradients were 2.106 x 10/sup -3/ and 2.688 x 10/sup -3/ (gm/cm/sup 3/)/100 ft in sandstones and shales respectively. Compressional (P-wave) and shear (S-wave) velocities from the long-spaced sonic log and bulk densities from the formation density log were used to compute in-situ elastic moduli, Poisson's ratio, V/sub p//V/sub s/, and bulk compressibility in two intervals of deep geopressured sandstone and shale in No. 2 Pleasant Bayou. Most computed values of these parameters seem reasonable. Improved accuracy of travel times from the long-spaced sonic log should permit more accurate depth-to-time correlation with seismic data.
Date: May 1, 1980
Creator: Gregory, A.R.
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

Resistivity, induced polarization, and self-potential methods in geothermal exploration

Description: An overview of the literature is presented. This is followed by a statement of some elementary electromagnetic theory necessary to establish the MKS system of units and the fundamental physics governing electrical methods of exploration. Next there is presented a reasonably detailed discussion of the electrical properties of earth materials including normal mode of conduction, surface conduction, electrode polarization, membrane polarization, semiconduction, melt conduction, real and complex resistivity, and the origin of self-potentials in geothermal systems. To illustrate how electrical methods are used within the framework of integrated geological, geochemical, and geophysical exploration, the case history of the Monroe-Red Hill hot springs system is presented.
Date: January 1, 1982
Creator: Ward, S.H. & Sill, W.R.
Partner: UNT Libraries Government Documents Department

Magnetic induction technique for mapping vertical conductive fractures: electronic design

Description: This report is the last in a series that describes the preliminary design of an instrument capable of mapping conductive fractures deep below the surface of the earth. Earlier reports dealt with theoretical analysis, the general status of the instrument development, and materials vendor searches. Here, attention is focused on the electronics design and prototype hardware to perform the mapping task. A phase-sensitive detector is described that has a sensitivity in the tens of nanovolts. Coil-switching circuitry is also described, as well as a downhole data link tailor-made for this particular instrument's needs.
Date: September 1, 1978
Creator: Landt, J.A.; Koelle, A.R.; Trump, M.A. & Nickell, J.D. Jr.
Partner: UNT Libraries Government Documents Department

Assessment of the geothermal resources of Kansas

Description: This volume contains BHT correction factor analysis, repeatability study of control well, and an analysis of thermal logging method, including thermal data for some deep wells in Kansas. (MHR)
Date: June 1, 1982
Partner: UNT Libraries Government Documents Department

Magnetic induction technique for mapping vertical conductive fractures: theory of operation

Description: Utilization of a hot dry rock geothermal resource requires circulation of a fluid (water) through fractures in the rock. The Los Alamos Scientific Laboratory is presently investigating the feasibility and economics of tapping this energy resource. Presently, the fractures in the rock are created by conventional hydraulic fracturing techniques. Accurate determination of the geometry of the fracture system is required so that boreholes may be drilled to complete the circulation system. The theory of a technique designed to map vertical conductive fractures located in resistive rock is presented. The technique is based on magnetic induction. Fracture thickness and strike can be determined from measurements made in a single borehole.
Date: July 1, 1978
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

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

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

Thin films for geothermal sensing: Final report

Description: The report discusses progress in three components of the geothermal measurement problem: (1) developing appropriate chemically sensitive thin films; (2) discovering suitably rugged and effective encapsulation schemes; and (3) conducting high temperature, in-situ electrochemical measurements. (ACR)
Date: September 1, 1987
Partner: UNT Libraries Government Documents Department