For manufacturing general purpose underground heat and obtaining minerals weak area (depth is 13-30 kilometers)

摘要

PCT No. PCT/CH90/00212 Sec. 371 Date Jul. 11, 1991 Sec. 102(e) Date Jul. 11, 1991 PCT Filed Sep. 10, 1990 PCT Pub. No. WO91/03690 PCT Pub. Date Mar. 21, 1991.The hot-weak-rock process for overcoming the technical limitation inherent to the Hot-Dry-Rock Process, of not being able to overcome the shear strength of the rock beyond a certain depth in order to create heating surfaces through HYDRAFRAC. The hot-weak-rock process creates a heating zone in an area of the continental lithosphere in which the shear strength of the hot rock suddenly decreases with increasing overburden and the HYDRFRAC necessary to create heating surfaces is effectuated under the hydrostatic pressure of a water column in a correspondingly deep and lined boring. A technically easily generated additional pressure component is applied to the water column in the boring to create the initial cracks in the lower, unlined section of the boring.