A multi-coal seam capsule isolation 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 anti-permeability 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 kind of clean energy, but it is also a source of disaster for coal mine production. The geological conditions of coal occurrence in my country are complex, mainly relying on underground mining. With the increase of mining depth, the gas content of coal seams gradually increases, the pressure of coal seam gas increases, the risk of outburst increases, and the difficulty of outburst prevention becomes more and more difficult. 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 t...

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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