Download or read book Reservoir Modeling and Prediction at Pleasant Bayou Geopressured Geothermal Reservoir written by and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Modeling and prediction of geopressured-geothermal reservoirs is an excellent example of an engineering problem that can be solved through many different means. The problem may be approached from a purely numerical viewpoint, where a successful history match ''demonstrates'' the validity of the reservoir model, or from an analytical point of view. Each method has its own inherent limitations and weaknesses. Such limitations can be minimized by using some combination of both numerical and analytical methods, taking advantage of the strengths of each without the attendant weaknesses. This paper describes a combined numerical/analytical approach to reservoir engineering at the Pleasant Bayou geopressured-geothermal reservoir. A reservoir description had previously been developed, through which a successful history match was performed. Certain details of the reservoir can also be obtained through analysis of pressure and flow transients; these can then be used to constrain the numerical model. Methods for extracting such reservoir data are discussed, and the manner in which they can be used as constraints in the numerical models are presented.
Download or read book Session written by and published by . This book was released on 1992 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: ''Overview of Geopressured-Geothermal'' by Allan J. Jelacic; ''Geothermal Well Operations and Automation in a Competitive Market'' by Ben A. Eaton; ''Reservoir Modeling and Prediction at Pleasant Bayou Geopressured-Geothermal Reservoir'' by G. Michael Shook; ''Survey of California Geopressured-Geothermal'' by Kelly Birkinshaw; and ''Technology Transfer, Reaching the Market for Geopressured-Geothermal Resources'' by Jane Negus-de Wys.
Download or read book An Integrated Approach to Reservoir Engineering at Pleasant Bayou Geopressured Geothermal Reservoir written by and published by . This book was released on 1992 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: A numerical model has been developed for the Pleasant Bayou Geothermal-Geopressured reservoir. This reservoir description is the result of integration of a variety of data, including geological and geophysical interpretations, pressure transient test analyses, and well operations. Transient test analyses suggested several enhancements to the geologic description provided by University of Texas Bureau of Economic Geology (BEG), including the presence of an internal fault not previously identified. The transient tests also suggested water influx from an adjacent aquifer during the long-term testing of Pleasant Bayou; comparisons between transient test analyses and the reservoir description from BEG suggests that this fault exhibits pressure-dependent behavior. Below some pressure difference across the fault, it remains a no-flow barrier; above this threshold pressure drop the barrier fails, and fluid moves across the fault. A history match exercise is presented, using the hypothesized {open_quotes}leaky fault.{close_quotes} Successful match of 4 years of production rates and estimates of average reservoir pressure supports the reservoir description developed herein. Sensitivity studies indicate that the degree of communication between the perforated interval and the upper and lower sands in the reservoir (termed {open_quotes}distal volume{close_quotes} by BEG) impact simulation results very little, whereas results are quite sensitive to storage and transport properties of this distal volume. The prediction phase of the study indicates that Pleasant Bayou is capable of producing 20,000 STB/d through 1997, with the final bottomhole pressure approximately 1600 psi above abandonment pressure.
Download or read book Well Test Analysis and Reservoir Modeling of Geopressured geothermal Systems includes Topical Reports on Analyses for written by and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Automated inversion of pressure transient data from the Pleasant Bayou and Gladys McCall geopressured test wells has allowed the resolution of several outstanding questions concerning the two reservoirs. The added accuracy of the interpretation of the various data sets from each well provides convincing evidence that the formation response of each of the reservoirs behaved in an essentially linear fashion throughout its multi-year depletion/recovery test history. The only exception was in the immediate vicinity of the sandface; the skin factor in each of the wells varies during the course of its test history (see Appendices for detailed discussions of the variations and the likely causes of the variations for each well). (a) The six bottomhole pressure transient tests of Pleasant Bayou Well No. 2 over a twelve year period (1980-1992) yield estimates for the permeability-thickness product that are in excellent agreement (kh = 3.665 D-m). Inversion of the 45-day buildup portion of the 1980 RLT yields an estimate of X{sub a} = 869 m as the distance from the well to the nearest boundary. The inversion of the data from the other five tests, of much shorter duration, yield estimates in the range X{sub a} = 427-503 m. The RLT estimate would normally be given much more credence. The failure, repair and resetting of the gauge after the first ten days of the start of the buildup test, however, may have affected the RLT data. Calculations are employed to estimate bottomhole pressures from surface recordings subsequent to removal of the bottomhole gauge following the 1992 70-hr buildup test. These estimated values were combined with the 70-hr data to form the 111-day (from September 12, 1992 through January 1, 1993) LTT buildup test data set. The LTT data were inverted to yield an estimate of X{sub a} = 452 m. Since this is in agreement with the range of estimates from the five short-term bottomhole test, we believe the range X{sub a} = 427-503 m to represent the best estimate for the distance from the well to the nearest boundary. The simulation model presented in Appendix B used L1 = 990 m (Figure 3 in Appendix B) as the distance from the test well to the nearest boundary. The simulation model could probably be improved using a smaller value for L1. The actual location of the boundary to the south of the well is not known from the available geological information. (b) The five bottomhole pressure transient tests of Gladys McCall Well No. 2 over an eight-year period (1983-1991) yield estimates for the permeability-thickness product that differ significantly from each other. The differences, however, can be explained by the partial plugging of the near-well formation during an aborted attempt to inject a scale-inhibitor pill in May 1985, followed by subsequent scouring out the pill precipitates by the flowing fluid during the May 1985-August 1987 production testing. The partial plugging of the near-well formation in conjunction with a known shale stringer that prevents vertical communication in sand 8 (Figure 2 in Appendix A) would reduce the apparent value of kh to about sixty percent of the original RLT value of 13.44 D-m. Inversion of the 79-hr (1985) and 92-hr (1986) buildup tests yield kh estimates of 7.69 and 8.86 D-m, respectively. Inversions of the valid MRT (1987) and FDT (1991) pressure transient data yield estimates very near the original RLT value. The reinterpretation of the MRT data represents a correction of our earlier conclusion (in Appendix A); we now believe that the data from the first and second gauges employed during the MRT are incompatible. Data from the first (''old'') gauge during the drawdown portion of the MRT could not be adequately corrected for the observed drift in the recorded data. Only the second (''new'') gauge data are considered reliable and inversion of the buildup data it recorded yields the estimate for kh that is in agreement with estimates obtained from inversion of the RLT and FDT pressure transient data.
Download or read book Pleasant Bayou Geopressured Geothermal Reservoir Analysis January 1991 written by and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Many sedimentary basins contain formations with pore fluids at pressures higher than hydrostatic value; these formations are called geopressured. The pore pressure is generally well in excess of hydrostatic and the fluids vary in scalinity, temperature, and dissolved methane. As part of its program to define the magnitude and recoverability of the geopressured-geothermal energy resource, the US Department of Energy has drilled and tested deep wells in geopressured formations in the Texas-Louisiana Gulf Coast region. Geological information for the Pleasant Bayou geopressured geothermal resource is most extensive among the reservoirs tested. Earlier testing of the DOE well (Pleasant Bayou Well No. 2) was conducted in several phases during 1979-1983. Long-term testing was resumed in May 1988 and is currently in progress. This report summarizes the pertinent field and laboratory test data available through December 31, 1990. A numerical reservoir simulator is employed as a tool for synthesizing and integrating the reservoir information, formation rock and fluid properties data from laboratory tests, well data from the earlier testing (1979-1983), and the ongoing long-term production testing (1988-1990) of Pleasant Bayou Well No. 2. A reservoir simulation model has been constructed which provides a detailed match to the well test history to date. This model is constructed within a geologic framework described by the Texas Bureau of Economic Geology and relies heavily on the pressure transient data from the 1980 Reservoir Limits Test in conjunction with the 1988-1990 production testing.
Download or read book Gulf Coast Geopressured geothermal Reservoir Simulation written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The results of the short-term production tests run on the Pleasant Bayou No. 2 well are summarized. These tests were analyzed using conventional pressure test analysis methods. The effects of reservoir heterogeneties onm production behavior and, in particular, permeability distribution and faulting of reservoir sand were studied to determine the sensitivity of recovery to these parameters. A study on the effect of gas buildup around a producing well is reported. (MHR).
Download or read book The interrelationships and variations of the resistivity porosity and permeability as functions of pressure in a geopressured reservoir written by Thomas Robert Ashman and published by . This book was released on 1981 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluid production from both normally and abnormally pressured reservoirs has long been recognized as a function of the formation fluid properties and the reservoir rock parameters. Fluid production itself, however, changes the stress state of the reservoir resulting in rock deformation which affects total fluid and, therefore, energy recovery. This study was undertaken as part of a project to determine and predict the effects of fluid production on the Pleasant Bayou geopressured, geothermal reservoir in Brazoria County, Texas. Data was collected from triaxial loading tests conducted on sandstone samples cored from the potential producing horizons of the reservoir. All tests were conducted at overburden and pore pressures which simulated insitu conditions. Empirical relations were developed which reflected changes in the resistivity, porosity, and permeability as functions of the effective stress. Relationships among the parameters were found to be of practical use in predicting formation changes as the reservoir stress state changed due to fluid withdrawal. Results showed that the resistivity, porosity, and permeability were dependent on the effective stresses in the reservoir. The cementation factor in Archie's equation was also found to be a pressure function.
Download or read book Research to Understand and Predict Geopressured Reservoir Characteristics with Confidence written by and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Department of Energy's Geopressured Geothermal Program has sponsored a series of geoscience studies to resolve key uncertainties in the performance of geopressured reservoirs. The priority areas for research include improving the ability to predict reservoir size and flow capabilities, understanding the role of oil and gas in reservoir depletion and evaluating mechanisms for reservoir pressure maintenance. Long-term production from the Gladys McCall well has provided the basis for most of the current research efforts. The well was shut-in on October 29, 1987, for pressure recovery after producing over 27 million barrels of brine with associated gas. Geologic investigations are evaluating various mechanisms for pressure maintenance in this reservoir, including recharge from adjacent reservoirs or along growth faults, shale dewatering, and laterally overlapping and connected sandstone layers. Compaction studies using shale and sandstone core samples have provided data on the relationship between rock compression and reservoir pressure decline and the correlation to changes in porosity and permeability. The studies support the use of a porosity-coupled reservoir simulation model which has provided an excellent match to the well's production history. 10 refs., 3 figs.
Download or read book Preliminary Reservoir and Subsidence Simulations for the Austin Bayou Geopressured Geothermal Prospect written by and published by . This book was released on 1978 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the last several years, the University of Texas at Austin (UTA) has analyzed the geopressured tertiary sandstones along the Texas Gulf Coast with the objective of locating prospective reservoirs from which geothermal energy could be recovered. Of the ''geothermal fairways'' (areas with thick sandstone bodies and estimated temperatures in excess of 300 F), the Brazoria fairway appears most promising and the Austin Bayou Prospect has been developed within this fairway. A test well (DOE 1 Martin Ranch) is currently being drilled in this area. Pending the availability of actual well test data, estimated reservoir properties have been employed in numerical simulations to study the effects of variations in reservoir properties on the projected long-term behavior of the Austin Bayou Prospect. The simulations assess the sensitivity of the reservoir behavior to variations is estimated sandstone/shale distribution, shale compressibility, and vertical shale permeability. Further, hypothetical properties for the stress-deformation behavior of the rock formations were employed in a very preliminary study of the potential ground surface displacements that might accompany fluid production.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1994 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book U S Gulf Coast Geopressured Geothermal Reservoir Simulation written by and published by . This book was released on 1979 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book U S Gulf Coast Geopressured geothermal Reservoir Simulation written by R. C. MacDonald and published by . This book was released on 1982 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book U S Gulf Coast Geopressured Geothermal Reservoir Simulation written by S. K. Garg and published by . This book was released on 1977 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book U S Gulf Coast Geopressured Geothermal Reservoir Simulation written by R. M. Knapp and published by . This book was released on 1985 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book U S Gulf Coast geopressured geothermal reservoir simulation written by R. M. Knapp and published by . This book was released on 198? with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book U S Gulf Coast Geopressured geothermal Reservoir Simulation written by University of Texas at Austin and published by . This book was released on 1979 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geopressured Geothermal Reservoir and Wellbore Simulation written by S. K. Garg and published by . This book was released on 1978 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt:
