A double well closed type enhanced geothermal system

Abstract

The invention discloses a double-well closed-type enhanced geothermal system, which includes tight layers, leakage layers and aquifers in the ground, and also includes injection wells, production wells and horizontal wells connecting the injection wells and production wells. Outer wells and horizontal wells are coated with well pipes, and part of the well pipes in horizontal wells are covered with cement sheaths. The horizontal well is set in the lost zone and aquifer, and the cement sheath is made of high thermal conductivity material and cement compound. In the invention, graphene is respectively compounded with drilling mud, well cement and well pipe to form a composite material with high thermal conductivity, so as to strengthen the heat conduction performance of formation, well cement and well pipe. Since the drilling process often encounters water-free lost zones or aquifers, horizontal wells are drilled in these layers, and high thermal conductivity composite drilling mud is used to deliberately leak into the formation to improve the thermal conductivity of the formation.

Description

technical field [0001] The invention relates to the technical field of geothermal heating, in particular to a double-well closed enhanced geothermal system. Background technique [0002] For areas where hydrothermal resources are not very rich, if you want to exploit geothermal energy on a large scale, there are generally two ways, one is to use the traditional enhanced geothermal system (EGS), and the other is to use closed deep well heat exchangers . Traditional enhanced geothermal systems use hydraulic fracturing to create high-permeability fractures in low-permeability tight layers to achieve convective heat transfer between fluid and tight layers. This heat transfer method can indeed greatly improve the heat transfer of water and rock, and is A promising way to achieve thermal energy extraction from hot dry rock. However, the hydraulic fracturing required by the enhanced geothermal system is expensive, the direction of the fracture is difficult to control, the fluid i...

AI Technical Summary

Problems solved by technology

Although DBHE is a promising geothermal development technology, it mainly relies on the heat conduction of the tight layer to transfer the heat from the surrounding dense layer to the wellbore. Due to the low thermal conductivity of the tight layer, the heat extraction power of a single well is small.

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