A non-negative pressure geothermal recharge system and recharge method

Abstract

The invention discloses a non-negative pressure geothermal recharge system and a recharge method, wherein the recharge system comprises a steady flow tank and a nitrogen compensation device. The inlet of the tank is connected to the inlet of the geothermal tail water, a first flow meter is arranged between the inlet of the geothermal tail water and the inlet of the steady flow tank, the outlet of the steady flow tank is connected to the geothermal recharge well, and the The wellhead is provided with a sealed recharge wellhead device and a wellhead pressure gauge, a first electric control valve and a second flowmeter are arranged between the outlet of the steady flow tank and the geothermal recharge well in sequence, and the nitrogen compensation device passes nitrogen gas through the wellhead. The compensation pipelines are respectively connected to the steady flow tank and the geothermal recharge well. The invention converts the unstable pressure at the inlet of the geothermal tail water into a controllable pressure in the steady flow tank by setting the steady flow tank, and adjusts the steady flow through the nitrogen compensation device. The pressure in the tank and the geothermal recharge well is balanced, so as to ensure the steady operation of the recharge system.

Description

technical field [0001] The invention relates to the field of geothermal development, in particular to a non-negative pressure geothermal recharge system and a recharge method. Background technique [0002] Geothermal tail water recharge refers to a technology that reinjects the geothermal fluid whose temperature has dropped after utilization into the thermal reservoir through the recharge well. Geothermal tail water recharge is of great significance to prolong the service life of thermal fields, reduce environmental pollution caused by heating tail water discharge, and prevent land subsidence caused by mining. [0003] According to the different pressure methods of fluid injection into the reservoir, geothermal tail water recharge methods can be divided into pressurized recharge and negative pressure recharge. When the aquifer of the reinjection well has poor permeability and the water absorption capacity of the formation cannot meet the actual recharge demand, external for...

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Problems solved by technology

Due to the negative pressure recharge, the water absorption capacity of the formation is greater than the tail water flow of the system, often resulting in the formation of a vacuum column in the heating system, which affects the heating effect on the one hand, and brings difficulties to geothermal dynamic monitoring on the other hand. For example, the monitoring error of recharge flow is large

Because the conventional negative pressure suppressor will cause air to enter the recharge system, which will cause the water quality of the recharge tail water to change and block the recharge channel, so a device is urgently needed to ensure the pressure balance in the recharge system

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