Shale reservoir methane in-situ multi-stage pulse energy-gathering blasting fracturing method

Abstract

The invention relates to a shale reservoir methane in-situ multi-stage pulse energy-gathering blasting fracturing method. The method is suitable for fracturing and permeability increasing of a deep shale reservoir to increase extraction of shale gas. A perforating gun is used for energy-gathered perforation to generate an energy-gathered slot in the well wall of a horizontal well, the position of an energy-gathered blasting pipe is adjusted to enable an energy-gathered hole to correspond to the energy-gathered slot, after in-situ desorption methane of a shale reservoir reaches the blasting concentration, ignition is carried out to release a combustion improver, first-stage blasting fracturing is carried out through high-temperature and high-pressure gas generated by synergistic blasting of the combustion improver and methane gas, and then methane continues to be desorbed to reach the blasting concentration, secondary ignition is carried out to release the combustion improver to carry out secondary blasting fracturing, multi-stage pulse energy gathering blasting fracturing is carried out on the shale reservoir in a circulating and reciprocating mode, the blasting-fracture mutual promotion fracture forming process is formed, and relay type deep-penetration large-range fracture forming is achieved. The method does not need to consume a large amount of water resources, desorbs methane in situ, does not have the processes of overground transportation, underground putting, mixing and the like, and has very obvious advantages of safety, economy and environmental protection.

Description

technical field [0001] The invention relates to an in-situ multi-stage pulse energy-concentrating explosion fracturing method for methane in shale reservoirs, especially suitable for deep shale reservoirs with low porosity, low permeability and difficult extraction, where shale gas exploitation must be artificially intensified. Fracture shale reservoirs to build a three-dimensional flow fracture network for shale gas. Background technique [0002] Shale gas usually exists in gas-producing rocks such as mud shale in an adsorbed and free state. Reservoirs generally have the characteristics of low porosity and low permeability, so the development of shale gas is very difficult. Therefore, to achieve commercial exploitation of shale gas, shale gas reservoirs must be artificially fractured to form a connected fracture network to achieve the purpose of increasing shale gas production. [0003] Hydraulic fracturing technology, as the most effective measure to increase shale gas pr...

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Problems solved by technology

[0004] Technical problem: The purpose of this invention is to overcome the deficiencies in the prior art, to provide a shale reservoir methane in-situ multi-stage pulse energy-concentrating explosion fracturing method, for the development and reduction of shale gas in deep shale reservoirs Traditional shale gas development costs are high and environmental pollution is serious

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