Method for reinforcing gas extraction through coal seam drilling jet fracturing and mining pressure cooperated effect

Abstract

The invention discloses a method for reinforcing gas extraction through coal seam drilling jet fracturing and mining pressure cooperated effect. According to a mining pressure time-space distributionrule caused in the underground roadway excavating and stope face stoping process, pre-extracted gas drilling reasonable positions, perpendicular to a stope face, of sides of an air inlet roadway and an air return roadway of a working face are determined; and according to the mining pressure time-space distribution rule and fracturing parameter design in front of the working face, a fracturing extracting integrated drilling position, a grouped fracturing length, segmented fracturing intervals and other technical parameters perpendicular to the direction of the stope face are determined, and thehydraulic jet fracturing technology is used for carrying out retreating type grouped segmented fracturing on a coal seam. Under the fracturing effect and mining pressure cooperated coupling effect, afracturing fracture can be further expanded, the large-range area coal seam precise, uniform and full-covering dual pressure relief permeability improvement effect is achieved, and pre-extracted gasdrilling and fracturing extracting integrated drilling are used for achieving coal seam fracturing and gas efficient safe extraction.

Description

technical field [0001] The invention relates to the technical field of gas drainage, in particular to a method for enhancing gas drainage through the synergistic effect of coal seam drilling jet fracturing and mining pressure. Background technique [0002] With the continuous increase of coal mining depth and mining intensity, mine gas disasters are becoming more and more prominent, which restricts the safety of coal production and seriously affects the mine production efficiency. More and more attention has been paid to the prevention and control of gas disasters. At the same time, coalbed methane (coalbed methane) is also a kind of efficient clean energy. Theoretical research and field practice show that the extraction of coalbed methane before coal mining is a fundamental measure to prevent and control mine gas disasters; at the same time, the extracted gas is also It can be used as clean energy for power generation, heating, etc. In the past ten years, hydraulic fractu...

AI Technical Summary

Problems solved by technology

The traditional whole-stage fracturing technology cannot accurately control the actual fracturing position and direction, the distribution of fractures is uneven, the impact range of fractures is small, the gas extraction rate is low, and it is difficult to carry out continuous and efficient operation.

With the development of related technologies such as kilometer drilling rigs for coal mines and coal mine fracturing pump stations, some scholars and field engineers have begun to explore long-drilled segmental fracturing technology in coal mines. Layer-length drilling, segmental fracturing, high-efficiency drainage of coal roadway strip gas and regional outburst elimination method, Chinese patent application CN102704905A discloses a segmental hydraulic fracturing coal seam pressure relief device and pressure relief method, Chinese patent CN205063929U discloses a This is an integrated segmented hydraulic fracturing device for underground pressure sealing in coal mines. The segmented fracturing methods for a class of coal seams or coal rock layers disclosed above all use capsule sealing, which has high requirements for hole sealing and sealing construction and is very difficult, and is prone to Seal failure causes staged fracturing failure

Chinese patent application CN103233768A discloses a segmented fracturing pressure relief method for underground coal seam horizontal drilling. A single curved screw rod is used to drill multiple branch holes on the main horizontal hole, and then seal the main horizontal hole, and the whole section is held for pressure fracturing. Not only the installation process of staged fracturing equipment, pipelines and hole sealers is complicated, but also the number of fracturing stages and the location of fracturing are difficult to control

Chinese patent application CN109236261A discloses a large-displacement hydraulic jet layered fracturing string and a fracturing method for oil and gas wells, and Chinese patent application CN102877824A discloses a method for horizontal well hydraulic jet segmental multi-cluster fracturing. The application of hydraulic jet fracturing technology in underground oil and gas wells, but the perforation and fracturing equipment in the oil and gas field is large in size, complex in process, and high in cost, and is often not suitable for underground coal mines, resulting in unsatisfactory coal seam fracturing effects

More importantly, the existing various fracturing technologies do not consider the spatio-temporal relationship with the impact of mining pressure

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