Directional hydraulic fracturing method based on concentrated energy blasting

Abstract

Disclosed is a directional hydraulic fracturing method based on energizing blasting. The method includes: drilling a fracturing bore at a preset position of a working face roof or a coal body, determining depth and angle of the fracturing bore according to site conditions and project needs, the depth of the fracturing bore is at least 5m, sending an energizing tube deeply into the fracturing bore and sealing the fracturing bore to perform directional energizing blasting; directional blasting generated fracture gaps with certain depth are formed on the inner wall of the fracturing bore along an energizing hole after the blasting, cleaning the fracturing bore with water, mounting a hole seal shallowly at the blasting section of the fracturing bore to seal the bore, performing high pressure water injection to the fracturing bore, and the directional blasting generated fracture gaps expands under the water pressure so that the directional hydraulic fracturing is achieved. By the method, expanding directions of the fracture gaps during the hydraulic fracturing can be controlled, water pressure energizing blasting fracturing can also be applied to eliminate potential safety hazard caused by the blasting, shock wave influence and seismic wave influence to surrounding rocks are reduced greatly, drilling space is increased, and drilling cost and labor intensity are lowered. In addition, the directional hydraulic fracturing method is simple in operation process, dynamite-saving and fine in fracturing effect.

Description

technical field [0001] The invention relates to a hydraulic fracturing method, in particular to a directional hydraulic fracturing method for energy-concentrated blasting of coal and rock mass. Background technique [0002] The problem of coal-rock dynamic disasters induced by coal mining in my country has always been very prominent. Among them, rock burst is the most difficult coal-rock dynamic disaster. Studies have shown that rock burst mostly occurs in coal seams with hard roofs, especially in hard thick sandstone roofs with large thickness, high strength, strong integrity and compact structure, and the coal is medium-hard, brittle and elastic. in the coal seam. The directional treatment of hard roof weakening and coal seam weakening is an effective way to prevent rock burst. Ordinary borehole explosive blasting method will form a relatively strong shock wave, which will cause a large stress disturbance to the coal and rock mass, and there will be hidden dangers of in...

AI Technical Summary

Problems solved by technology

The blasting method of ordinary drilling explosives will form a relatively strong shock wave, which will cause a large stress disturbance to the coal and rock mass, and there will be hidden dangers of induced dynamic disasters, and it will be difficult to achieve directional treatment if the damage to the local surrounding rock is large.

In addition, the simple hydraulic fracturing method cannot control the direction of crack propagation in the hole.

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