Novel geothermal underground heat exchanger structure and construction method thereof

Abstract

The invention discloses a novel geothermal underground heat exchanger structure which comprises a heat reservoir located in a stratum, a first opening well cementation section penetrating through the stratum and the heat reservoir, a second opening well cementation section arranged below the first opening well cementation section and a center pipe penetrating through the first opening well cementation section and the second opening well cementation section. The first-opening well cementation section comprises a first-opening casing pipe, the second-opening well cementation section comprises a second-opening casing pipe, the outer side of the first-opening casing pipe and the outer side of the second-opening casing pipe are each sequentially sleeved with a casing pipe wall and a well wall, and the invention further discloses a construction method of the novel geothermal underground heat exchanger structure, and the construction method is suitable for the technical field of geothermal exploitation. The technical problems of low heat exchange amount and low heat exchange speed of an existing mid-deep layer medium-low temperature water type geothermal technology without taking water are solved, the heat exchange amount and the heat exchange speed of a geothermal well adopting the technology without taking water without taking water are improved, the economical efficiency of the geothermal well adopting the technology without taking water without taking water is enhanced, and popularization of the technology without taking water without taking water is promoted.

Description

technical field [0001] The invention belongs to the technical field of geothermal exploitation, in particular to a novel geothermal underground heat exchanger structure and a construction method thereof. Background technique [0002] For medium-deep medium-low temperature water-type geothermal resources, the existing geothermal exploitation method in my country is to extract underground hot water to the ground, transport it to the customer through the underground heating pipe network, and exchange the heat energy of the hot water through heat exchange. To achieve the purpose of heating in winter, it is widely used in heating, physiotherapy, planting, breeding and other fields. [0003] Due to the extensive development and utilization of geothermal resources in my country in the early stage, a large amount of geothermal heating tail water was discharged, which not only caused waste of resources, caused water and soil pollution, but also exacerbated geological disasters such as...

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Problems solved by technology

[0003] Due to the extensive development and utilization of geothermal resources in my country in the early stage, a large amount of geothermal heating tail water was discharged, which not only caused waste of resources, caused water and soil pollution, but also exacerbated geological disasters such as land subsidence and ground fissures.

Due to the complex geological conditions of sandstone thermal storage in my country and the huge reservoir pressure, the tail water recharge is difficult and the cost of tail water recharge is high

At the same time, tail water recharge may also cause reservoir pollution, which in turn pollutes and integrates the deep groundwater system, resulting in an ecological disaster

[0004] However, the existing downhole heat exchangers for mid-to-deep medium-low temperature water-type geothermal "take heat but not water" have the following disadvantages: 1. The heat transfer is low, and the heat transfer is only 1 / 1 of the heat transfer of traditional underground hot water extraction. Less than 10; 2. The heat transfer speed is slow, and the bottom hole temperature cannot be recovered quickly; 3. The economic benefit is poor, the return on investment is low, and the cost recovery period is long

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