In-situ combustion and explosion fracturing method for methane in shale gas reservoir fractures

Abstract

The invention discloses an in-situ combustion and explosion fracturing method for methane in shale gas reservoir fractures. The method comprises the steps that a ground working system is built; high-pressure inert gas abrasive jet formed by mixing natural quartz sand and high-pressure inert gas is pumped into the target working position where the fracturing tool stops; high-pressure inert gas is pumped into the annulus between the shaft and the coiled tubing, and mixed fluid composed of a solid combustion improver, a fracturing propping agent and the inert gas is pumped into the annulus between the shaft and the coiled tubing; a wellhead is opened, and inert gas flows back to the ground; oxygen is injected into the annulus, methane is pumped into a pipe cavity of the continuous oil pipe, and the methane is pumped into the annulus through the continuous oil pipe by the fracturing tool and mixed with the oxygen in the annulus; igniting to detonate the methane-oxygen mixture; the shale reservoir is continuously impacted through secondary fire blast in the crack; and blasting fracturing operation at multiple positions in the whole shaft is completed. The method is high in rock breaking and fracturing degree, ideal in anti-reflection effect and good in environmental protection performance, and efficient and green development of shale gas resources can be achieved.

Description

technical field [0001] The invention belongs to the technical field of unconventional oil and gas exploitation and shale gas reservoir stimulation and transformation, and in particular relates to a methane in-situ blasting and fracturing method in shale gas reservoir fractures. Background technique [0002] At present, among the proven shale gas reserves, China is the country with the largest shale gas reserves in the world. As of 2019, the cumulative proven reserves have exceeded 6.5 trillion cubic meters. Most of the newly added proven reserves of natural gas are also shale gas. At present, some countries represented by the United States have realized the commercial exploitation of shale gas, while China started late in this regard, and with the continuous exploration and discovery, China's shale gas reservoirs are more geological than other countries. It is more complex, the quality is poor, and the exploitation is more difficult. Therefore, it is urgent to develop new t...

AI Technical Summary

Problems solved by technology

At present, hydraulic fracturing is the main method of reservoir stimulation, but the use of this technology consumes a lot of water resources. In addition, as the shale reservoirs being explored are buried deeper and deeper, the degree of rock breaking and fracturing by conventional hydraulic fracturing methods is low, increasing The permeability effect is not ideal, and it can no longer effectively deal with the problems of strong plasticity of reservoir rock and large in-situ stress. Therefore, it is urgent to develop a new fracturing process to realize the green and efficient development of unconventional natural gas.

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