High-voltage electric pulse hydraulic fracturing method for coal and rock mass and guiding fracture forming device

Abstract

The invention belongs to the technical field of unconventional natural gas exploitation through high-voltage electric pulse hydraulic fracturing, and particularly relates to a high-voltage electric pulse hydraulic fracturing method for a coal and rock mass and a guiding fracture forming device. The method includes the steps that before unconventional gas production, drilling is carried out on the surface of a production area, guided fractures are set on a wellbore by using the guiding fracture forming device, then a wellhead is sealed, and fracturing is conducted on the wellbore by using a high-voltage electric pulse hydraulic fracturing technology, so that ideal cracks are generated in coal rock, a migration channel of unconventional natural gas in a coal rock layer is increased and opened up, and the gas mining efficiency is improved. The guiding fracture forming device can walk in a drilling well, and an arranged fracture forming part can rotate around a shaft along a guiding part and move in the axial direction. According to the guiding fracture forming device, the fracture forming part can do combined motion of combining the axial direction and the winding axis along the guiding part, so that the fracture forming part can form a guide fracture in the wellbore according to a preset path by controlling the motion of the fracture forming part.

Description

technical field [0001] The invention belongs to the technical field of mining unconventional natural gas by high-voltage electric pulse hydraulic fracturing of coal and rock mass, and specifically relates to a method for high-voltage electric pulse hydraulic fracturing of coal and rock mass and a guiding crack opening device. Background technique [0002] With the rapid development of my country's economy, the demand for energy has been increasing in recent years, coupled with the adjustment of the traditional energy structure (that is, reducing the dependence on coal, oil, natural gas, etc.), making coalbed methane, shale gas, The exploitation of unconventional natural gas such as oil sandstone gas has drawn more and more attention from the state. China is rich in coalbed methane and shale gas resources, among which coalbed methane is the third largest country after Russia and Canada, and the proven resource reserve of shale gas is about 30.7×10 12 m 3 , mainly distribute...

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Problems solved by technology

Although the United States, Canada and other countries already have some mature coalbed methane and shale gas development technologies, due to the deep burial, tight reservoirs, low permeability and strong heterogeneity of coalbed methane and shale gas in my country, etc. The characteristics lead to difficulties in gas extraction, and foreign unconventional natural gas extraction methods cannot be fully applied to my country

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