Coal-bed gas well electric pulse blockage releasing and permeation enhancing method

Abstract

A coal-bed gas well electric pulse blockage releasing and permeation enhancing method is suitable for high-efficient mining of coal-bed gas wells. According to the blockage releasing and permeation enhancing method, a positive electrode coal-bed gas well shaft and a negative electrode coal-bed gas well shaft are constructed from the ground to a coal bed; cracks in the coal bed are closed gradually or blocked by granular impurities along with coal bed gas extraction after hydrofracturing, so that the gas yield is reduced; at the moment, a conductive ion solution is injected into the positive electrode coal-bed gas well shaft, and the portion, between the positive electrode coal-bed gas well shaft and the negative electrode coal-bed gas well shaft, of the coal bed is filled with the conductive ion solution; then a positive electrode and a negative electrode are put downwards to the coal bed permeation forecast increasing portions in the positive electrode coal-bed gas well shaft and the negative electrode coal-bed gas well shaft correspondingly; the portion, between the positive electrode and the negative electrode and filled with the conductive ion solution, of the coal bed is broken down through discharging of high voltage electropulses, great energy forms impact waves to act on the coal bed, the closed cracks in the coal bed are opened again and extend, the granules blocking the cracks are removed, the number of the cracks in the coal bed is effectively increased, and crack connectivity is improved.

Description

technical field [0001] The invention relates to a method for removing plugging and increasing permeability by electric pulse, in particular to a method for removing plugging and increasing permeability by electric pulse suitable for coal bed gas wells with low permeability. Background technique [0002] Coalbed methane, as a clean energy source, has great development potential. However, at present most of the coal seams in our country have the characteristics of low air permeability, and there are problems such as poor coal seam air permeability, low mining rate, and high mining cost, which seriously restrict the development and utilization of coalbed methane in my country. Among them, hydraulic fracturing is the most commonly used technical means in coalbed methane exploitation. However, the number of fractures formed in the coal seam by conventional hydraulic fracturing technology is small, and the extension range of the fractures is small, and the overall fracturing effe...

AI Technical Summary

Problems solved by technology

For example, the patent publication number is CN104061014A, and the name is "a high-power electric detonation-assisted hydraulic fracturing stimulation method for coalbed methane wells". The discharge electrode is powered by a high-voltage pulse power supply, and the water medium is broken down to form a shock wave in the water that acts on the surrounding water. Coal body, cracks are formed in the surrounding coal body, but the shock wave propagates to the surrounding in a spherical wave, the attenuation speed is fast, the energy consumption is large, and the efficiency is low. The effective cracking range of this method is very small

At present, there are problems such as high pulse voltage, high risk, large shock wave energy consumption, small cracking range, and low efficiency in the current electric pulse coal seam permeability enhancement technology.

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