Segmented fixed-point hydraulic fracturing device and method for underground coal mine drilling

Abstract

A segmented fixed-point hydraulic fracturing device and method for underground drilling in a coal mine, wherein the method mainly includes a segmented fixed-point hydraulic fracturing device in an underground coal mine: installing a segmented fixed-point fracturing device in an open hole until the predetermined fracturing Target layer; 2 Grouting and fixing holes: After using the plug to seal the orifice annulus, use the grouting pump to inject cement slurry into the segmented fixed-point fracturing device, and then return to the Orifice; 3. Pressure displacement fluid: press the rubber pad and displacement fluid into the casing, and keep the pressure until the rubber pad is pressed against the check valve and wait for coagulation; 4. Fracturing: inject fracturing fluid into the casing, press The fracturing fluid breaks through the cement weak surface of the one-way valve structure and then fractures the target layer. The invention provides a device and method for segmental fixed-point hydraulic fracturing and hole fixing for underground drilling in coal mines, which solves the problem of complex and cumbersome steps in the existing pore forming and segmental hydraulic fracturing technology, and improves the hole fixing and segmental hydraulic fracturing. The quality of fracturing has realized the integration of hole fixing and segmented fixed-point hydraulic fracturing.

Description

technical field [0001] The invention relates to the field of hydraulic fracturing for underground drilling in coal mines, in particular to a segmented and fixed-point hydraulic fracturing device and method for underground drilling in coal mines. Background technique [0002] At present, mine gas control mainly relies on gas drainage technology, and the direct means of gas drainage is to construct gas drainage boreholes to extract gas through negative pressure. Existing drilling gas extraction methods mainly include 1. back drilling open hole gas drainage method, 2. lowering the screen pipe gas drainage in the whole hole section of the whole protection hole, 3. preventing local injection holes, hole collapse and necking Gas drainage method for local protective holes with dragging casing. [0003] Generally speaking, when the coal seam has good porosity and high air permeability, the gas drainage method with back drilling works better, but when the geological structure is com...

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Problems solved by technology

[0003] Generally speaking, when the coal seam has good porosity and high air permeability, the gas drainage method with back drilling works better, but when the geological structure is complex, the coal is soft, the buried depth is large, and the coal seam has poor porosity and air permeability. It is easy for the hole wall to deform or collapse to block the gas drainage channel, and the porosity and drainage effect are often not ideal

When the screen pipes are lowered for gas extraction, the screen holes are prone to be blocked by coal blocks, which affects the extraction effect. In addition, when hydraulically fracturing coal seams, the latter two methods need to be lowered into the fracturing pipes before perforating and fracturing. The process is complicated and the pressure is high. The filtration loss is large, and the effect of coal seam fracture network reconstruction is not good

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