a co 2 Method for displacing high-salt brine in deep formation

Abstract

The present invention provides a CO 2 A method for displacing deep hypersaline brine in formations, comprising the following steps: converting captured CO 2 Transport to mining site via CO 2 The compressor will CO 2 Compress to supercritical state and inject supercritical CO 2 The injection well is pumped into the high-salt brine layer deep in the formation. At the same time, the high-salt brine is extracted in the extraction well, and the brine in the extracted high-salt brine is separated from the CO by a separation device. 2 Separation, deep processing and purification of the separated brine, and the separation of CO 2 by CO 2 The reinjection device repeatedly injects into the CO 2 into the compressor, and further pumped into the high-salt brine layer deep in the formation to circulate and displace the high-salt brine. This method can effectively alleviate the CO 2 Due to the serious pressure accumulation and salt rock precipitation problem during the simple injection process, the escaped CO 2 The reinjection realizes zero emission and reaps double benefits of economy and environmental protection.

Description

technical field [0001] The invention relates to a method for preparing high-salt brine in deep formations, in particular to a method using CO 2 A method of displacing high-salt brine deep in the formation, and at the same time, CO 2 It is stored underground and belongs to the technical field of environmental governance and resource exploitation. Background technique [0002] Brine resources are a huge treasure house of liquid mineral resources. Comprehensive development is not only urgently needed for the development of the national economy, but also can produce obvious economic and social benefits. The developed bromine, iodine and potassium chloride are scarce chemical raw materials in China. Comprehensive development and utilization can save a lot of foreign exchange for the country; Great value. [0003] At present, there are more and more systems used for the development of deep underground brine resources, and have a certain commercial basis. With the continuous de...

AI Technical Summary

Problems solved by technology

Although this mining method has the advantages of supporting facilities and low manufacturing cost, it is easily limited by the physical and chemical properties of the injected water and has its disadvantages

There are some unfavorable factors in using water as the displacement medium: 1. The water injected into the ground is seriously lost, with a loss rate as low as 10% and as high as 78%

2. For some active rock formation substances, water is prone to chemical reactions with it, affecting the normal pumping and injection between injection wells and production wells

3. The water injected into the ground will dilute the brine, and the brine concentration will increase the production cost due to too low concentration

[0006] However, simple injection of CO into high salinity brine 2 , on the one hand will cause CO 2 The amount of dissolution and mineral capture is significantly reduced, and high salinity will cause a large amount of salt rock precipitation near the injection well, which is not conducive to CO 2 Continuous injection of

On the other hand, it will cause problems such as formation pressure accumulation and salt water replacing shallow water.

However, the increase of formation pressure near the wellbore causes the overlying formation (cap rock) to rupture or the fault to reactivate, which easily induces CO 2 Leakage reduces the sealing safety factor; the replacement of shallow water by salt water will have an impact on the original groundwater system, which may cause the high-salt brine in the deep stratum to migrate to the shallow water body, causing pollution of the shallow water body

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