Download or read book Analysis of Reservoir Fracture Sealing in an Active Geothermal System Kawerau Geothermal Field New Zealand written by Aaron J. Lister and published by . This book was released on 2018 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fractures in Geothermal Reservoirs written by Geothermal Resources Council and published by . This book was released on 1982 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Tracer Analysis in a Fractured Geothermal Reservoir Field Results from Wairakei New Zealand written by Martin Peter Fossum and published by . This book was released on 1982 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the New Zealand Geothermal Workshop written by and published by . This book was released on 1990 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the 14th New Zealand Geothermal Workshop 1992 written by Stuart Frank Simmons and published by . This book was released on 1992 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fracture Characterization in Geothermal Reservoirs Using Time lapse Electric Potential Data written by Lilja Magnúsdóttir and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The configuration of fractures in a geothermal reservoir is central to the performance of the system. The interconnected fractures control the heat and mass transport in the reservoir and if the fluid reaches production wells before it is fully heated, unfavorable effects on energy production may result due to decreasing fluid enthalpies. Consequently, inappropriate placing of injection or production wells can lead to premature thermal breakthrough. Thus, fracture characterization in geothermal reservoirs is an important task in order to design the recovery strategy appropriately and increase the overall efficiency of the power production. This is true both in naturally fractured geothermal systems as well as in Enhanced Geothermal Systems (EGS) with man-made fractures produced by hydraulic stimulation. In this study, the aim was to estimate fracture connectivity in geothermal reservoirs using a conductive fluid injection and an inversion of time-lapse electric potential data. Discrete fracture networks were modeled and a flow simulator was used first to simulate the flow of a conductive tracer through the reservoirs. Then, the simulator was applied to solve the electric fields at each time step by utilizing the analogy between Ohm's law and Darcy's law. The electric potential difference between well-pairs drops as a conductive fluid fills fracture paths from the injector towards the producer. Therefore, the time-lapse electric potential data can be representative of the connectivity of the fracture network. Flow and electric simulations were performed on models of various fracture networks and inverse modeling was used to match reservoir models to other fracture networks in a library of networks by comparing the time-histories of the electric potential. Two fracture characterization indices were investigated for describing the character of the fractured reservoirs; the fractional connected area and the spatial fractal dimension. In most cases, the electrical potential approach was used successfully to estimate both the fractional connected area of the reservoirs and the spatial fractal dimension. The locations of the linked fracture sets were also predicted correctly. Next, the electric method was compared to using only the simple tracer return curves at the producers in the inverse analysis. The study showed that the fracture characterization indices were estimated somewhat better using the electric approach. The locations of connected areas in the predicted network were also in many cases incorrect when only the tracer return curves were used. The use of the electric approach to predict thermal return was investigated and compared to using just the simple tracer return curves. The electric approach predicted the thermal return curves relatively accurately. However, in some cases the tracer return gave a better estimation of the thermal behavior. The electric measurements are affected by both the time it takes for the conductive tracer to reach the production well, as well as the overall location of the connected areas. When only the tracer return curves are used in the inverse analysis, only the concentration of tracer at the producer is measured but there is a good correlation between the tracer breakthrough time and the thermal breakthrough times. Thus, the tracer return curves can predict the thermal return accurately but the overall location of fractures might not be predicted correctly. The electric data and the tracer return data were also used together in an inverse analysis to predict the thermal returns. The results were in some cases somewhat better than using only the tracer return curves or only the electric data. A different injection scheme was also tested for both approaches. The electric data characterized the overall fracture network better than the tracer return curves so when the well pattern was changed from what was used during the tracer and electric measurements, the electric approach predicted the new thermal return better. In addition, the thermal return was predicted considerably better using the electric approach when measurements over a shorter period of time were used in the inverse analysis. In addition to characterizing the fracture distribution better, the electric approach can give information about the conductive fluid flowing through the fracture network even before it has reached the production wells.
Download or read book Geothermal Reservoir Engineering in Perspective written by UNU Geothermal Training Programme (Iceland). and published by . This book was released on 1985 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geothermal Reservoir Engineering Research in New Zealand written by and published by . This book was released on 1978 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although nowadays much of the New Zealand geothermal reservoir research effort is still being concentrated on the older fields of Wairakei and Broadlands there has been a definite advance over recent years in our approach to the studies. On the practical side, long term reinjection trials are now in progress at Broadlands, and drilling, for field evaluation, is well underway at Ngawha, a field characterized by a steam discharge coupled with a hydrostatic pressure gradient. On the theoretical side, well pressure transient analysis and reservoir behavior modeling are probably the primary interests. For the former both multi-element computer modeling programs and two-phase pressure diffusion analysis (Grant, 1978, Grant and Sorey, 1979) are being used by M.A. Grant, E. Bradford and F. Sutton (AMD*) and M.L. Sorey (PEL). Geometry and boundary influences are dominant and estimated steam flows are higher than are consistent with the Corey (1954) expressions for relative permeability. Both of these effects are probably due to the fracture permeability of the reservoirs. A. McNabb (AMD) is currently taking this into account by determining the response to discharge in a fracture-block medium. He is working with 100 meter blocks, consistent with data from lumped parameter models and from well records, with a block permeability of 10−15 m2. Reservoir behavior modeling is probably the research area of greatest current interest with most research groups here involved to some extent. The models range over a wide spectrum, from extreme simplification to sophisticated detail. At the simpler extreme is the model of J. Elder (AU). This consists of two resistors and a condenser in electrical analog form but is coupled with models of the well system and the above surface plant to enable overall system effects and interactions to be assessed.
Download or read book Reservoir scale Fracture Permeability in the Dixie Valley Nevada Geothermal Field written by and published by . This book was released on 1998 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wellbore image data recorded in six wells penetrating a geothermal reservoir associated with an active normal fault at Dixie Valley, Nevada, were used in conjunction with hydrologic tests and in situ stress measurements to investigate the relationship between reservoir productivity and the contemporary in situ stress field. The analysis of data from wells drilled into productive and non-productive segments of the Stillwater fault zone indicates that fractures must be both optimally oriented and critically stressed to have high measured permeabilities. Fracture permeability in all wells is dominated by a relatively small number of fractures oriented parallel to the local trend of the Stillwater Fault. Fracture geometry may also play a significant role in reservoir productivity. The well-developed populations of low angle fractures present in wells drilled into the producing segment of the fault are not present in the zone where production is not commercially viable.
Download or read book Kawerau Geothermal Field written by Gregory Bignall and published by . This book was released on 2012 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterization of Fractured Geothermal Reservoirs Based on Production Data written by Egill Júlíusson and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Reservoir characterization is one of the most important and challenging parts of running a successful geothermal operation. Characterization requires thorough understanding of the physics that govern the flow of mass and energy through the reservoir. As for most subsurface modeling endeavors, the inability to measure the actual value of properties in the geothermal system make it necessary to strike a balance between what is included in the reservoir model and what is known about the physical processes that might take place in the subsurface. This balance should reflect the decisions that need to be made based on the model, and the data available for model calibration. In this work, a number of methods were developed for characterizing well-to-well connections in fractured geothermal reservoirs. These methods were based on production data that are commonly recorded in geothermal fields, i.e. pressure, flow rate, tracer and temperature. A key aspect in the developing this work, for multiwell applications, was to find the link between the various types of models, and understand how they could be combined to estimate well-to-well properties. The estimation of these properties relied on regression analysis, where an effort was made to balance the complexity of the regression model with the information required from the given data source. The combined characterization defined a work flow that would be well-suited to characterize fractured geothermal systems, with low compressibility characteristics. An effort was made to illustrate the usefulness of the characterization method to tackle important reservoir engineering problems. This was done by formulating and solving a flow rate scheduling problem for a geothermal field. The results showed that considerable gains in efficiency could be made, given a set of well-calibrated interwell relationships.
Download or read book Fracture Characterization in Enhanced Geothermal Systems by Wellbore and Reservoir Analysis written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report highlights the work that was done to characterize fractured geothermal reservoirs using production data. That includes methods that were developed to infer characteristic functions from production data and models that were designed to optimize reinjection scheduling into geothermal reservoirs, based on these characteristic functions. The characterization method provides a robust way of interpreting tracer and flow rate data from fractured reservoirs. The flow-rate data are used to infer the interwell connectivity, which describes how injected fluids are divided between producers in the reservoir. The tracer data are used to find the tracer kernel for each injector-producer connection. The tracer kernel describes the volume and dispersive properties of the interwell flow path. A combination of parametric and nonparametric regression methods were developed to estimate the tracer kernels for situations where data is collected at variable flow-rate or variable injected concentration conditions. The characteristic functions can be used to calibrate thermal transport models, which can in turn be used to predict the productivity of geothermal systems. This predictive model can be used to optimize injection scheduling in a geothermal reservoir, as is illustrated in this report.
Download or read book Petroleum Abstracts Literature and Patents written by and published by . This book was released on 1987 with total page 1348 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Summary of Reservoir Engineering Data written by J. W. Pritchett and published by . This book was released on 1979 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Blue Book on Geothermal Resources written by and published by . This book was released on 1999 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Volcanology and Geothermal Energy written by Kenneth Wohletz and published by . This book was released on 1992 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most high-temperature geothermal resources develop in volcanic regions, but very few have been successfully explored and developed despite the ever-growing need for renewable energy resources. This is particularly true of the many developing countries that exist in volcanic regions with potential geothermal resources. Because exploration techniques, which must be adapted from the oil industry, are expensive and uncertain, economic growth in these countries remains contingent on the availability and cost of oil. Bridging the gap between academic geologists and drilling engineers, Volcanology and Geothermal Energy is a practical and thorough guide to planning and operating a successful exploration project. It describes the potential geothermal reservoirs associated with volcanoes and volcanic regions and uses recent advances in volcanology to offer many examples of how geological field data give evidence of the location, nature, and size of a geothermal resource. Most high-temperature geothermal resources develop in volcanic regions, but very few have been successfully explored and developed despite the ever-growing need for renewable energy resources. This is particularly true of the many developing countries that exist in volcanic regions with potential geothermal resources. Because exploration techniques, which must be adapted from the oil industry, are expensive and uncertain, economic growth in these countries remains contingent on the availability and cost of oil. Bridging the gap between academic geologists and drilling engineers, Volcanology and Geothermal Energy is a practical and thorough guide to planning and operating a successful exploration project. It describes the potential geothermal reservoirs associated with volcanoes and volcanic regions and uses recent advances in volcanology to offer many examples of how geological field data give evidence of the location, nature, and size of a geothermal resource.
Download or read book Fluid Fluid Interactions written by Axel Liebscher and published by Walter de Gruyter GmbH & Co KG. This book was released on 2018-12-17 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 65 of Reviews in Mineralogy and Geochemistry attempts to fill this gap and to explicitly focus on the role that co-existing fluids play in the diverse geologic environments. It brings together the previously somewhat detached literature on fluid–fluid interactions in continental, volcanic, submarine and subduction zone environments. It emphasizes that fluid mixing and unmixing are widespread processes that may occur in all geologic environments of the entire crust and upper mantle. Despite different P-T conditions, the fundamental processes are analogous in the different settings.
