Method and system for extracting heat energy of hot dry rocks

Abstract

The invention relates to a method and system for extracting heat energy of hot dry rocks. The method includes that an injection well system, a horizontal well system and an output well system are arranged in a heat reservoir stratum of the dry hot rocks, a circulation channel is formed by connecting the injection well system, the horizontal well system and the output well system in sequence, heat-carrying agent fluid is adjusted to reach appropriate flow through an adjustment valve of the injection well system, the heat-carrying agent fluid is injected into different injection well pipes, the fluid flows through the injection well system, the horizontal well system and the output well system in sequence, and the heat of the hot dry rocks is absorbed, high-efficiency extracting of the heat energy of the hot dry rocks is achieved, and meanwhile the purposes of keeping relative purity of an heat-carrying agent, not running the heat-carrying agent off and not polluting the heat reservoir stratum of the dry hot rocks are achieved. The system for extracting the heat energy of the hot dry rocks comprises the injection well system, the horizontal well system and the output well system. By means of the method and system for extracting the heat energy of the hot dry rocks, self-sustaining cycle of the heat-carrying agent fluid can be achieved without consuming pump power, and pressure loss of the heat-carrying agent fluid in an energy conversion system and in a flow channel can be provided on the ground. The method and system for extracting the heat energy of the hot dry rocks are widely applied to an enhancement type geothermal system of geothermal exploitation of the hot dry rocks.

Description

technical field [0001] The invention relates to a method and system for extracting geothermal energy, in particular to a method and system for extracting heat energy from dry hot rocks. Background technique [0002] Geothermal resources are mainly divided into hydrothermal type and dry hot rock type. At present, the hydrothermal type medium and low temperature geothermal mainly used by countries in the world only accounts for a very small part of the proven geothermal resources, while the medium and high temperature hot dry rock geothermal resources are rich in reserves and high in temperature on the earth. According to the latest data from relevant state departments, the total amount of hot dry rock resources at a depth of 3-10 kilometers in mainland my country is equivalent to 860 trillion tons of standard coal; (3.25 billion tons of standard coal) 5300 times. Therefore, the development of medium and high temperature hot dry rock geothermal is very likely to make a major ...

AI Technical Summary

Problems solved by technology

[0004] Due to the characteristics of low permeability, low porosity and deep reservoir location of hot dry rock, its development faces many scientific and technical challenges, the biggest challenge is the low efficiency of geothermal utilization, including: (1) Formation heat extraction Low efficiency (US demonstration projects show heat extraction efficiency of 1-5% for hot dry rock projects) and (2) high loss rate of underground heat exchange fluid (approximately 7-12%)

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