A kind of high pressure water explosion and co 2 Coalbed methane displacement and drainage technology combined with fracturing

Abstract

The invention discloses a coalbed methane displacement extraction process combining high-pressure water explosion and CO2 fracturing, including determination of ground stress state, drilling and sealing of the sealing section, drilling and slotting, charging, water injection and sealing of the hole 1. The steps of high-pressure water explosion cracking, supercritical or liquid CO2 cracking and gas extraction. Among them, supercritical or liquid CO2 is mixed with ceramsite proppant. During the continuous fracturing process of liquid CO2, the microseismic monitor is used to monitor the expansion and extension of explosive cracks in real time. Stop fracking after effect. When guiding slotting, according to the number of slotting slots and the set distance between adjacent slotting slots, the drilling and slotting can be performed one by one after the holes are drilled first, or the drilling and slotting can be performed after each drilling. Alternately done. The beneficial effect of the invention is that it can effectively increase the permeability of the low-permeability coal-bed methane reservoir, reduce the amount of construction, and have high extraction efficiency of the coal-bed methane.

Description

technical field [0001] The invention relates to the technical field of fracturing-displacement drainage of coalbed methane, in particular to a high-pressure water explosion and CO 2 CBM displacement and drainage technology combined with fracturing. Background technique [0002] Coal bed gas or gas (the main component is methane, chemical formula CH 4 ) is a kind of clean energy, and it is also an important factor causing gas accidents in coal mines. CBM drainage is an important measure to improve energy structure and reduce coal mine gas disasters. China's coalbed methane mining technology is dominated by hydraulic fracturing. Hydraulic fracturing is a fracturing technology widely used in fields such as oil and gas stimulation, geothermal resource development, and nuclear waste storage. Hydraulic fracturing is a method of fracturing and increasing permeability by injecting high-pressure water into the reservoir through a pump injection system to fracture the formation. ...

AI Technical Summary

Problems solved by technology

The main problems are as follows: 1) It consumes too much water and is unsustainable; 2) Hydraulic fracturing often produces only one main fracture that is symmetrically distributed along the fracturing borehole, perpendicular to the direction of the minimum principal stress, and expands and extends along the direction of the maximum principal stress , the anti-permeability effect is not very obvious, and the conductivity is unstable; 3) The water-based fracturing fluid system is easy to pollute the groundwater, which is not environmentally friendly; 4) The fracturing of underground coal and rock reservoirs rarely considers the influence of in-situ stress, which is unscientific

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