High-pressureholepacking and pressure relief protection method for coal strata

Abstract

The invention discloses a high-pressure holepacking and pressure relief protection method for coal strata. The method comprises the following steps: firstly, a hole is drilled, and a hole packer is extended into thedrilled hole; secondly, water is injected into thehole to pack thehole; thirdly, the hole packer keeps pressure of the packed hole to fracture the coal strata; fourthly, fracturing is stopped; fifthly, the hole packer keeps pressure and reduces and releases pressure stage by stage; and sixthly, the hole packer is recovered. A one-way safety valve is changed into a two-way safety valve, the valve is controlled by cooperation with a pipe, conventional high-pressure water can be injected into the drilled hole to seal the hole and fracture the coal strata, pressure keeping and relief of the hole packer can be conducted, and water pressure in the drilled hole is acquired by a pressure gauge; when fracturing is stopped, the two-way safety valve of the hole packer cooperates withtheone-way valve to maintain pressure of the hole packer stopping water injection; stage-by-stage pressure relief is achieved by adjusting an external pipe cut-off valve and a pressure regulating valve,high-pressure water infracturing holes can flow out through the two-way safety valve, in-situ pressure maintenance and pressure relief of the hole packer is achieved, a high-pressure rubber expansionhose is less likely to be ejected from the drilled hole,high-speed friction with the fractured holes is prevented, and the service life is long.

Description

technical field [0001] The invention belongs to the technical field of coal rock formation fracturing hole sealing and pressure relief, and in particular relates to a high-pressure hole sealing and pressure relief protection method for coal rock formations. Background technique [0002] Accidents such as gas ejection, coal and gas outburst, gas explosion, and rock burst occur from time to time in our country. Coal formation water injection, coal formation hydraulic fracturing and other technologies are effective means to prevent and control gas disasters and rock burst disasters. Safe and effective hole sealing is the primary condition for efficient water injection and hydraulic fracturing. The conventional sealing method is to inject high-pressure water into the high-pressure rubber expansion hose, and the high-pressure rubber expansion hose expands and presses the hole wall to seal the hole. After the water in the high-pressure rubber expansion hose reaches a certain pres...

AI Technical Summary

Problems solved by technology

When the water injection is stopped or the pump is accidentally stopped, the pressure in the hole sealed by the existing hole sealer is much greater than the pressure in the high-pressure rubber expansion hose, and the high-pressure rubber expansion hose is ejected from the hole due to insufficient sealing pressure, causing great problems. Once the operator is at the drilling position, the consequences will be unimaginable after stopping the water injection, and the huge impact force and impact speed will cause the sealing rubber outside the high-pressure rubber expansion hose to be damaged by the friction of the drilling hole, and the sealing effect will be poor when used again. The service life is short, and the existing sealing method cannot achieve effective and controllable pressure relief for the high-pressure water in the borehole

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