PDF Publication Title:
Text from PDF Page: 043
444 Chapter 4 Review of EGS and Related Technology – Status and Achievements by bringing treated waste water from the city of Santa Rosa and from Lake County, for injection augmentation. At Dixie Valley, pressure drawdown due to lack of natural recharge and limited injection into the reservoir was reversed by injecting all produced fluids, careful selection of injector locations, and augmentation of injection from shallow, nonpotable groundwater sources on site. • High flow rates with long path lengths are needed. By looking at natural hydrothermal systems, we know that we need to have production of about 5 MWe per production well, which requires flow rates ranging from 30 to 100 kg/s, depending on the fluid temperature. At the same time, we need a large heatexchange area or long residence time for water to reheat to production temperatures; this could imply large pressure drops. Better understanding of successful natural systems (in comparable geological settings) should lead to improved methods of generating artificially enhanced geothermal systems. For instance, the residence time of water injected at Dixie Valley is threesix months, and the production wells show little or no cooling due to the aggressive injection program. At Steamboat, though, the residence time for the water is closer to two weeks and there is fairly significant cooling. The well spacing between injectors and producers at Dixie Valley is about 800 m, and there are probably at least two fractures with a somewhat complex connection between the injectors and producers resulting in a long fluidpath length. At the Steamboat hydrothermal site, the distance between producers and injectors is more than 1,000 m; but because there are many fractures, the transmissivity is so high that there is low residence time for injected fluids. At the East Mesa hydrothermal site, the reservoir is in fractured sandstone, and the residence time varies from one part of the field to another. Some injectors perform well in the center of the field, while other injectors are in areas with either high matrix permeability in some zones or fractures that cause cold water to break through faster. The large volume of hot water stored in the porous matrix at East Mesa made it possible to operate the field for a long time before problems with cooling developed. • Stimulation is through shearing of preexisting fractures. In strong crystalline rock, hydraulic properties are determined by the natural fracture system and the stresses on that fracture system. The expectation of scientists planning the early experiments in enhancing geothermal reservoirs was that fracturing would be tensile. While it may be possible to create tensile fractures, it appears to be much more effective to stimulate preexisting natural fractures and cause them to fail in shear. Understanding the orientation of the stress field is crucial to designing a successful stimulation. Fortunately, in even the most unpromising tectonic settings, many fractures seem to be oriented for failure. At Cooper Basin, which is in compression, stimulation of two nearly horizontal preexisting fracture systems appears to have been successful in creating a connected reservoir of large size. Shearing of natural fractures increases hydraulic apertures, and this improvement remains after pressures are reduced. Fortunately, stress fields in strong rocks are anisotropic, so critically aligned natural joints and fractures shear at relatively low overpressures (210 MPa). • Fractures that are stimulated are those that will take fluid during prestimulation injection. The fractures that are found to be open and capable of receiving fluid during evaluation of the well before stimulation are almost always those that are stimulated and form largescale connections over a large reservoir volume. This may be because these fractures are connected anyway, or because the fractures that are open are those oriented with the current stress state. It is important, therefore, to target areas that will have some preexisting fractures due to their stress history and the degree of current differential stress. But even in areas with high compressional stresses – such as Cooper Basin in Australia – there are natural, open fractures. However, with present technology, we cannot create connected fractures where none exist. It may be possible to initiate new fractures, but it is not knownPDF Image | Review of EGS and Related Technology
PDF Search Title:
Review of EGS and Related TechnologyOriginal File Name Searched:
egs_chapter_4.pdfDIY PDF Search: Google It | Yahoo | Bing
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
IT XR Project Redstone NFT Available for Sale: NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Be part of the future with this NFT. Can be bought and sold but only one design NFT exists. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Turbine IT XR Project Redstone Design: NFT for sale... NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Includes all rights to this turbine design, including license for Fluid Handling Block I and II for the turbine assembly and housing. The NFT includes the blueprints (cad/cam), revenue streams, and all future development of the IT XR Project Redstone... More Info
Infinity Turbine ROT Radial Outflow Turbine 24 Design and Worldwide Rights: NFT for sale... NFT for the ROT 24 energy turbine. Be part of the future with this NFT. This design can be bought and sold but only one design NFT exists. You may manufacture the unit, or get the revenues from its sale from Infinity Turbine. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Supercritical CO2 10 Liter Extractor Design and Worldwide Rights: The Infinity Supercritical 10L CO2 extractor is for botanical oil extraction, which is rich in terpenes and can produce shelf ready full spectrum oil. With over 5 years of development, this industry leader mature extractor machine has been sold since 2015 and is part of many profitable businesses. The process can also be used for electrowinning, e-waste recycling, and lithium battery recycling, gold mining electronic wastes, precious metals. CO2 can also be used in a reverse fuel cell with nafion to make a gas-to-liquids fuel, such as methanol, ethanol and butanol or ethylene. Supercritical CO2 has also been used for treating nafion to make it more effective catalyst. This NFT is for the purchase of worldwide rights which includes the design. More Info
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
Infinity Turbine Products: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. May pay by Bitcoin or other Crypto. Products Page... More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)