Closed circulation well and development method of dry hot rock

Abstract

The invention discloses a closed circulation well and a development method of dry hot rock. The method comprises the following steps: choosing a target geothermal reservoir stratum, and determining the diameters of a vertical borehole and a branch borehole according to a discharge parameter and a pressure loss parameter; drilling the vertical borehole, and injecting cement paste to carry out wellcementation after enabling a first casing pipe to enter; drilling at least two branch boreholes; injecting the cement paste to carry out the well cementation after second casing pipes enter the branchboreholes; enabling a vacuum thermal insulation pipe to enter, wherein the vacuum thermal insulation pipe is successively connected with a heat exchanger, a circulating pump and a circular space between the vacuum thermal insulation pipe and the casing pipes through a ground pipe complex; and starting the circulating pump, wherein circulating fluid successively passes through the ground pipe complex, the circular space between the vacuum thermal insulation pipe and the casing pipes, the vacuum thermal insulation pipe and the ground pipe complex and then enters the heat exchanger to carry outcircular heat exchange. The method can realize the efficient and continuous exploitation of the dry hot rock at a relatively low cost.

Description

technical field [0001] The invention relates to the technical field of geothermal energy development, in particular to a closed circulation well and a development method for hot dry rock. Background technique [0002] The statements in this section only provide background information related to the present disclosure and may not constitute prior art. [0003] Hot dry rock is a high-temperature rock mass buried deep in the earth that does not contain or contain a small amount of fluids such as water or steam, and whose temperature is higher than 150 °C. The lithology is mainly compact metamorphic rock or granite. [0004] At present, the mining technology of hot dry rock is mainly based on Enhanced Geothermal Systems (EGS for short), that is, through hydraulic fracturing, chemical stimulation and other methods to increase the permeability of deep underground rocks to form underground artificial heat storage; After being heated in the underground artificial heat storage, the...

AI Technical Summary

Problems solved by technology

[0005] When using the existing EGS to develop hot dry rock, there are various problems that seriously limit the popularization and application of the EGS system

For example, when using EGS to develop hot dry rock, at least two wells need to be drilled, which are respectively used as injection wells and production wells, and the overall cost investment is huge; there is a possibility of inducing earthquakes in the process of hydraulic excitation by hydraulic fracturing; in addition, due to During the circulation process, the fluid working medium is in direct contact with the deep rock. The fluid working medium often contains corrosive components such as dissolved oxygen and chloride ions, as well as components that are easy to scale such as calcium ions and silicic acid. After the working medium flows into the pipeline and heat exchange equipment, it may Can cause corrosion and fouling problems

Images