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Analysis Of Injection Backflow Tracer Tests In Fractured Geothermal Reservoirs
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Book Synopsis Analysis of Injection-Backflow Tracer Tests in Fractured Geothermal Reservoirs by :
Download or read book Analysis of Injection-Backflow Tracer Tests in Fractured Geothermal Reservoirs written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Tracer tests have been an important technique for determining the flow and reservoir characteristics in various rock matrix systems. While the interwell tracer tests are aimed at the characterization of the regions between the wells, single-well injection-backflow tracer tests may be useful tools of preliminary evaluation, before implementing long term interwell tracer tests. This work is concerned with the quantitative evaluation of the tracer return profiles obtained from single well injection-backflow tracer tests. First, two mathematical models of tracer transport through fractures, have been reviewed. These two models are based on two different principles: Taylor Dispersion along the fracture and simultaneous diffusion in and out of the adjacent matrix. Then the governing equations for the transport during the injection-backflow tests have been solved. Finally the results were applied to field data obtained from Raft River and East Mesa geothermal fields. In order to determine the values of the parameters of the models that define the transport mechanisms through fractures a non-linear optimization technique was employed. 26 refs., 10 figs.
Book Synopsis Tracer Recovery and Mixing from Two Geothermal Injection-Backflow Studies by :
Download or read book Tracer Recovery and Mixing from Two Geothermal Injection-Backflow Studies written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Injection-backflow tracer testing on a single well is not a commonly used procedure for geothermal reservoir evaluation, and, consequently, there is little published information on the character or interpretation of tracer recovery curves. Two field experiments were conducted to develop chemical tracer procedures for use with injection-backflow testing, one on the fracture-permeability Raft River reservoir and the other on the matrix-permeability East Mesa reservoir. Results from tests conducted with incremental increases in the injection volume at both East Mesa and Raft River suggests that, for both reservoirs, permeability remained uniform with increasing distance from the well bore. Increased mixing during quiescent periods, between injection and backflow, at Raft River suggest an area near the well bore that has a hydrologic character different from the far well bore environment. Increased flow rates for East Mesa testing resulted in a general decrease in mixing. Comparison of recovery curves from the Raft River reservoir with those from the East Mesa reservoir suggests that mixing is greatest, and therefore permeability is greatest, in the fractured reservoir. These test results indicate that injection-backflow testing with tracers can be used successfully to characterize flow in the near-well bore environment.
Book Synopsis Response of East Mesa and Raft River Reservoirs to Injection - Backflow Testing by :
Download or read book Response of East Mesa and Raft River Reservoirs to Injection - Backflow Testing written by and published by . This book was released on 1983 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Analysis of tracer recovery curves from injection-backflow testing at two geothermal reservoirs reveals large differences in responsebetween the two. The east Mesa reservoir is in a layered sandstone matrix, and tracer behavior can be adequately described by porous media theory. As the volume of water injected into the reservoir increases and, consequently, the depth of penetration into the formation, the ratio of dispersive flux to advective flux decreases, indicating the increasing importance of advective transport. This effect can be seen in normalized tracer recovery curves that become more symmetrical with greater injection volume. At the Raft River site, the reservoir is dominated by a single major fracture zone. Injecting larger volumes of water into the fracture does not change the shape of the normalized tracer recovery curves. This indicates that the dispersion coefficient increases proportionally to the distance traveled by the injection front. Differences in the shape of tracer recovery curves are related to fundamental differences in reservoir characteristics. Long tails on the tracer recovery curves at Raft River suggest a dual porosity reservoir with a secondary fracture network connected to the major fracture. Such findings may considerably affect calculations of secondary heat recovery using injection wells.
Book Synopsis Flow and Contaminant Transport in Fractured Rock by : Jacob Bear
Download or read book Flow and Contaminant Transport in Fractured Rock written by Jacob Bear and published by Academic Press. This book was released on 2012-12-02 with total page 575 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past two or three decades, fractured rock domains have received increasing attention not only in reservoir engineering and hydrology, but also in connection with geological isolation of radioactive waste. Locations in both the saturated and unsaturated zones have been under consideration because such repositories are sources of heat and potential sources of groundwater contamination. Thus, in addition to the transport of mass of fluid phases in single and multiphase flow, the issues of heat transport and mass transport of components have to be addressed.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1992-10 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Use of Tracers to Analyze the Effects of Reinjection Into Fractured Geothermal Reservoirs by :
Download or read book The Use of Tracers to Analyze the Effects of Reinjection Into Fractured Geothermal Reservoirs written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper discusses the use of tracers as a reservoir engineering tool in fractured geothermal reservoirs. The principle concern in injecting cooler spent fluids into a fractured reservoir is that the fluids may move through high permeability channels and return to the production wells after contacting a relatively small volume of rock. As a consequence of this rapid transport, the fluids will be only partially reheated and after a short period time will effectively mine the heat from the limited volume of rock. The production wells will then experience a rapid and premature reduction in thermal output. Tracers can be used to infer the existence of high mobility conduits between injection and production wells and to monitor chemical changes of an injected fluid. Since tracer arrival precedes thermal breakthrough, tracer tests are a very useful forecasting tool.
Book Synopsis Analysis of Tracer and Thermal Transients During Reinjection by :
Download or read book Analysis of Tracer and Thermal Transients During Reinjection written by and published by . This book was released on 1989 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work studied tracer and thermal transients during reinjection in geothermal reserviors and developed a new technique which combines the results from interwell tracer tests and thermal injection-backflow tests to estimate the thermal breakthrough times. Tracer tests are essential to determine the degree of connectivity between the injection wells and the producing wells. To analyze the tracer return profiles quantitatively, we employed three mathematical models namely, the convection-dispersion (CD) model, matrix diffusion (MD) model, and the Avodnin (AD) model, which were developed to study tracer and heat transport in a single vertical fracture. We considered three types of tracer tests namely, interwell tracer tests without recirculation, interwell tracer tests with recirculation, and injection-backflow tracer tests. To estimate the model parameters, we used a nonlinear regression program to match tracer return profiles to the solutions.
Download or read book Injection Through Fractures written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Tracer tests are conducted in geothermal reservoirs as an aid in forecasting thermal breakthrough of reinjection water. To interpret tracer tests, mathematical models have been developed based on the various transport mechanisms in these highly fractured reservoirs. These tracer flow models have been applied to interpret field tests. The resulting matches between the model and field data were excellent and the model parameters were used to estimate reservoir properties. However, model fitting is an indirect process and the model's ability to estimate reservoir properties cannot be judged solely on the quality of the match between field data and model predictions. The model's accuracy in determining reservoir characteristics must be independently verified in a closely controlled environment. In this study, the closely controlled laboratory environment was chosen to test the validity and accuracy of tracer flow models developed specifically for flow in fractured rocks. The laboratory tracer tests were performed by flowing potassium iodide (KI) through artificially fractured core samples. The tracer test results were then analyzed with several models to determine which best fit the measured data. A Matrix Diffusion model was found to provide the best match of the tracer experiments. The core properties, as estimated by the Matrix Diffusion model parameters generated from the indirect matching process, were then determined. These calculated core parameters were compared to the measured core properties and were found to be in agreement. This verifies the use of the Matrix Diffusion flow model in estimating fracture widths from tracer tests.
Download or read book Workshop Report written by and published by . This book was released on with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Effects of Water Injection Into Fractured Geothermal Reservoirs by :
Download or read book Effects of Water Injection Into Fractured Geothermal Reservoirs written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Reinjection of water into fractured geothermal reservoirs holds potential both for improvement and degradation of total energy recovery. The replacement of reservoir fluid can mean support of placement of reservoir pressures and also more efficient thermal energy recovery, but at the same time the premature invasion of reinjected water back into production wells through high permeability fractures can reduce discharge enthalpy and hence deliverability and useful energy output. Increases in reservoir pressure and maintenance of field output have been observed in operating fields, but unfortunately so too have premature thermal breakthroughs. The design of reinjection schemes, therefore, requires careful investigation into the likely effects, using field experimentation. This paper summarizes field experience with reinjection around the world, with the intention of elucidating characteristics of possible problems. The results summarized in this paper fall into three categories of interest: permeability changes dye to injection (both increases and decreases); the path followed by injected water (as indicated by tracer tests); and the thermal and hydraulic influences of injection on the reinjection well itself and on surrounding producers. [DJE-2005].
Book Synopsis Tracer Flow in a Fractured Geothermal Reservoir Model by :
Download or read book Tracer Flow in a Fractured Geothermal Reservoir Model written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Tracer injection for identifying reservoir and transport parameters in geothermal sources has become an important procedure for designing an optimum reinjection program. Field tests have been analyzed using convection-diffusion equation to predict fracture size, width and probable thermal breakthrough times. The present study was conducted in a laboratory fractured reservoir model whose physical properties were known. The tracer, KI, breakthrough profiles were analyzed for different injection-production depth schemes. For different patterns different preferential flow paths existed which were then affected by flow through auxiliary paths. A correlation between heat and mass transport was used to define an apparent heat transfer coefficient for the flow. 3 tabs., 5 figs., 7 refs.
Book Synopsis Doublet Tracer Testing in Klamath Falls, Oregon by :
Download or read book Doublet Tracer Testing in Klamath Falls, Oregon written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A tracer test was carried out in a geothermal doublet system to study the injection behavior of a developed reservoir known to be fractured. The doublet produces about 320 gpm of 160 F water that is used for space heating and then injected; the wells are spaced 250 ft apart. Tracer breakthrough was observed in 2 hours and 45 minutes in the production well, indicating fracture flow. However, the tracer concentrations were low and indicated porous media flow; the tracers mixed with a reservoir volume much larger than a fracture.
Book Synopsis Groundwater Flow and Quality Modelling by : E. Custodio
Download or read book Groundwater Flow and Quality Modelling written by E. Custodio and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 834 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the NATO Advanced Research Workshop on Advances in Analytical and Numerical Groundwater Flow and Quality Modelling, Lisbon, Portugal, June 2-6, 1987
Book Synopsis Physical Model of a Fractured Reservoir by :
Download or read book Physical Model of a Fractured Reservoir written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of the physical modeling effort are to: (1) evaluate injection-backflow testing for fractured reservoirs under conditions of known reservoir parameters (porosity, fracture width, etc.); (2) study the mechanisms controlling solute transport in fracture systems; and (3) provide data for validation of numerical models that explicitly simulate solute migration in fracture systems. The fracture network is 0.57-m wide, 1.7-m long, and consists of two sets of fractures at right angles to one another with a fracture spacing of 10.2 cm. A series of injection-backflow tests, similar to those performed at the Raft River Geothermal field, was conducted. These included variable volume injection and injection-backflow tests with varying quiescent periods between injection and backflow. This latter series of tests was conducted with a range of flow fields passing through the model. recovery is related to the flow field in the physical model and model parameters. Longer quiescent times and greater flow fields result in a lower tracer recovery. A plot of the fractional tracer recovery against quiescent time results in a straight line. This relationship, combined with classical reservoir engineering data, can be used to predict aquifer flow rate and porosity from known injection volumes and tracer recovery.
Book Synopsis Tracer Test Analysis of the Klamath Falls Geothermal Resource by :
Download or read book Tracer Test Analysis of the Klamath Falls Geothermal Resource written by and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Two tracer tests on doublet systems in a fractured geothermal system were carried out in Klamath Falls, Oregon. The purpose of the tests were to obtain data which would lead to information about the reservoir and to test the applicability of current tracer flow models. The results show rapid breakthrough times and indicate fracture flow with vigorous mixing of injector fluid before production of same. This leads to the idea that thermal breakthrough is not directly related to tracer breakthrough in the Klamath Union doublet system. There has been no long-term enthalpy loss from exploiting the resource for 40 years. In order to reduce the data, models were developed to analyze the results. Along with a porous media flow model two mathematical models developed to analyze fractured geothermal systems are used to help decipher the various tracer return curves. The flow of tracers in doublet systems was investigated. A mathematical description is used for tracer flow through fractures as a function of time and various nonlinear parameters which can be found using a curve fitting technique. This allows the reservoir to be qualitatively defined. These models fit the data well, but point to the fact that future improvement needs to be considered for a clearer and more quantitative understanding of fractured geothermal systems. 22 refs., 32 figs., 11 tabs.
Book Synopsis Final Report of Geothermal Energy and High-Performance Drilling Collaborative Research Program (gebo) by : Cuvillier Verlag
Download or read book Final Report of Geothermal Energy and High-Performance Drilling Collaborative Research Program (gebo) written by Cuvillier Verlag and published by Cuvillier Verlag. This book was released on 2015-08-19 with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt: The superior goal of the gebo research association was making important contributions for the future reliable drilling under the existing “hot-hard-rock” conditions in Niedersachsen and their development to the geothermal drillings with sustainable geological subsurface heat exchangers. This goal should be achieved due to the solid research and innovative technology approaches in their combination within one concept for pioneering methods in deep geothermal drillings in hard rock, to be more exact - in interdisciplinary cooperation on engineers and scientists - in cooperation between industry and University, researchers and users Gebo research association comprised scientists and technicians of different research institutions and universities who are working in 33 projects. The individual projects were assigned to one of the 4 main research fields or focus areas. Gebo research association started its activities with 7 project partners participating: - Technische Universität Braunschweig (TUBS) - Technische Universität Clausthal (TUC) - Gottfried Wilhelm Leibniz Universität Hannover (LUH) - Georg-August-Universität Göttingen (UGOE) - Leibniz-Institut für Angewandte Geophysik (LIAG) - Bundesanstalt für Geowissenschaften und Rohstoffe (BGR) - Energie-Forschungszentrum Niedersachsen (EFZN) Baker Hughes, an industrial partner, participated in the association and supplies it with its experience and additional funds.
Download or read book JPT written by and published by . This book was released on 1987 with total page 1150 pages. Available in PDF, EPUB and Kindle. Book excerpt:
