Single-well fracture gravity self-circulation dry-hot-rock geotherm mining method

Abstract

The invention relates to the field of geothermal exploitation and provides a single-well fracture gravity self-circulation dry-hot-rock geotherm mining method. According to the method, perforation holes of different depths are utilized, the fracture size of a dry-hot-rock reservoir is increased through a water jet technology and a size fracture technology, and accordingly the upper area and the lower area of the reservoir communicate efficiently through fracture cracks; low-temperature heat-carrying fluid flows to the dry-hot-rock reservoir along the perforation holes in the upper portion after being injected in an annular mode, and then flows to the fracture cracks of the lower area under the actions of displacement pressure and gravity caused by the potential-energy difference of the fracture cracks of the upper portion and the lower portion; and finally, under the action of a ground suction pump, the heated heat-carrying fluid flows back to the ground along the perforation holes in the lower portion via a heat insulating oil pipe. According to the single-well fracture gravity self-circulation dry-hot-rock geotherm mining method, geothermal exploitation is carried out by annular cyclic injection and production of the heat-carrying fluid through the single-well oil pipe, and the expenses for drilling two injection and production wells in the conventional dry-hot-rock geotherm mining process is greatly reduced; and meanwhile, through use of the highly heat insulating oil pipe, the heat loss caused when the heat-carrying fluid is mined out of the oil pipe is reduced, and the heat collection capacity of the heat-carrying fluid is greatly improved.

Description

technical field [0001] The invention relates to the field of geothermal energy development, in particular to a geothermal method for single well fracturing gravity self-circulation mining of hot dry rock. Background technique [0002] Geothermal is one of the promising renewable energy sources. Compared with other new energy sources such as solar energy, wind energy and biomass energy, it has the advantages of wide distribution, little external influence (such as day and night, wind speed, temperature difference), low carbon emissions and maintenance costs. Features. China is located in the Pacific Rim geotropic region and the Mediterranean-Himalayan geotropical region, with abundant geothermal resources. However, traditional geothermal reservoirs are usually located near high ground temperature, active geological structures and / or active volcanoes. Limited by their location and reserves, the abundant geothermal energy cannot be reasonably utilized. With the advancement of...

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Problems solved by technology

Hot dry rock reservoirs are similar to tight oil and gas reservoirs. Using conventional vertical well fracturing technology, it is difficult to construct artificially fractured reservoirs with high permeability

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