Summary: | This report covers key aspects of Deep Seated Geothermal Resources (DSGR). The introductory section covers the importance of fractures for sufficient production and injection in geothermal reservoirs. The importance in of the temperature at which rock plasticity begins to occur in deep reservoirs is also covered. A conceptual model of a DSGR similar to Kakkonda, Japan resource is presented in order to discuss key issues of DSGR, including recharge, production, and injection. The Introductory Section is followed by a Discussion Section in which examples of DSGR wells are given using data from Japan, Iceland, and Italy. Estimates limiting pressures for the DSGR range of depths is given. It is shown that the state of the DSGR fluid can be determined from a plot of stable buoyancy curves. DSGR fracture and well dynamics, especially near the plastic transition temperature, and the flow patterns for DSGR production and injection wells are discussed, with emphasis on the major DSGR fractures. The report is concluded with a section in which conclusions are presented, and DSGR research and development is recommended.
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