Multi-coal-seam capsule isolation and separate layer fracturing device and method

Abstract

The invention discloses a multi-coal-seam capsule isolation and separate layer fracturing device and method. The fracturing device comprises a sleeve arranged in an open hole and penetrating multiple coal seams. Multiple prefabricated pipe sections corresponding to the multiple coal seams in position correspondingly are formed on the sleeve. The sleeve is sleeved with multiple capsule bags used for forming a capsule bag type well cementation structure together with the sleeve and rock stratums on the two sides of the coal seams. The adjacent capsule bags communicate through communicating pipes. One of the capsule bags is connected with a grouting system through a grouting pipe. A capsule hole-sealing fracturing device of an integrated structure is movably arranged in the sleeve and is connected with a fracturing pump set to be used for conducting hydraulic fracturing on the coal seams layer by layer, and before any coal seam is fractured, capsule hole-sealing structures are formed on pipe hole sections, behind and in front of the corresponding prefabricated pipe section, on the sleeve. According to the fracturing method, separate layer fracturing is conducted on the basis of the device mentioned above. The multi-coal-seam capsule isolation and separate layer fracturing device and method have the beneficial effects that the fracturing device is simple in structure, good in hole sealing effect and low in manufacturing cost; and the fracturing method is high in operability, high in efficiency and good in coal seam permeability increase effect.

Description

Technical field [0001] The invention relates to a hydraulic fracturing and permeation enhancement technology before coal seam gas extraction, in particular to a multi-coal seam capsule isolation layered fracturing device and method. Background technique [0002] Coal seam gas is a clean energy, but it is a source of disasters for coal production. The geological conditions for coal occurrence in our country are complex, mainly relying on underground mining. With the increase of mining depth, coal seam gas content gradually increases, coal seam gas pressure increases, the risk of outburst increases, and the difficulty of preventing outbursts is increasing. Existing coal mining face gas drainage is carried out by drilling wells in the coal seam in the transport lane and the return airway. For the coal seams with poor air permeability, it is usually necessary to perform hydraulic fracturing to increase the permeability. Existing methods are mostly suitable for fracturing and enhanci...

AI Technical Summary

Problems solved by technology

The gas drainage of the existing coal mining face is carried out by drilling along the bedding in the coal seam in the transportation roadway and the air return roadway respectively. For the coal seam with poor air permeability, it is usually necessary to carry out hydraulic fracturing to increase the gas permeability. Existing methods are mostly suitable for single coal seam fracturing and anti-permeability

At present, although there are some anti-permeability methods for multi-coal seams, either the operation method is complicated, or the hole-sealing device or hole-sealing structure is complicated. The sealing and fracturing time is long, and the cost of coal seam anti-permeability is high.

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