Supercritical carbon dioxide fracturing method and supercritical carbon dioxide fracturing system

Abstract

The invention discloses a supercritical carbon dioxide fracturing system and a supercritical carbon dioxide fracturing method for producing shale gas. The system comprises a storage tank, a booster pump, a heater, a cooler, a solid separator, a liquid separator, an air compressor and other accessories. The method comprises the steps that sufficient liquid carbon dioxide is stored in the storage tank before fracturing; carbon dioxide is heated to 31.1-120 DEG C by the heater, forms a supercritical state after boosted by the booster pump, and enters a fracturing site through a shaft; and a fractured medium is subjected to solid impurity separation by the solid separator and liquid impurity separation by the liquid separator, is finally cooled by the cooler to the storage temperature of the storage tank, and returns to the storage tank. The fracturing medium of the fracturing method can be recycled, so that the method has a good application prospect.

Description

technical field [0001] The invention relates to coal and gas mining technology, in particular to a shale fracturing method and system. Background technique [0002] When exploiting tight gas, especially shale gas, hydraulic fracturing is usually used to increase permeability, but the traditional hydraulic fracturing method has the following problems: [0003] 1) Hydraulic fracturing will cause water sensitivity, causing shale to expand and reduce its porosity and permeability; [0004] 2) The fracturing fluid of hydraulic fracturing cannot be recovered directly, and the fracturing fluid must be added with gel breaking fluid before it can be recovered, so the fracturing fluid recovery process is complicated; [0005] 3) A single shale gas well requires 150,000 to 300,000 tons of water for hydraulic fracturing. my country's gas-bearing shale is mainly distributed in the southwest region, which lacks water, so the cost of choosing hydraulic fracturing for shale gas exploitatio...

AI Technical Summary

Problems solved by technology

[0003] 1) Hydraulic fracturing will cause water sensitivity, causing shale to expand and reduce its porosity and permeability;

[0004] 2) The fracturing fluid of hydraulic fracturing cannot be recovered directly, and the fracturing fluid must be added with gel breaking fluid before it can be recovered, so the fracturing fluid recovery process is complicated;

[0005] 3) Hydraulic fracturing for a single shale gas well requires 150,000-300,000 tons of water. my country's gas-bearing shale is mainly distributed in the southwest region, which lacks water, so the cost of hydraulic fracturing is relatively high when exploiting shale gas

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