A protection method for high-pressure hole sealing and pressure relief in coal and rock formations

Abstract

The invention discloses a pressure relief protection method for high-pressure sealing holes in coal rock formations, comprising the steps of: 1. drilling and extending a hole sealing device into the drilling; 2. injecting water into the drilling and sealing the holes; 3. protecting the hole sealing device Sealing holes and fracturing coal formations; 4. Stop fracturing; 5. Keep the pressure of the hole sealer step by step to reduce the pressure; 6. Recover the hole sealer. The invention transforms the one-way safety valve into a two-way safety valve, and cooperates with the pipeline control valve to meet the requirements of conventional high-pressure water injection into the drilling hole sealing and fracturing of the coal rock formation. The water pressure in the borehole is obtained from the table. When the fracturing is stopped, the two-way safety valve of the hole sealer cooperates with the one-way valve to maintain the pressure of the hole sealer that stops water injection, and the pressure is relieved step by step by adjusting the external pipeline stop valve and pressure regulating valve. , and the high-pressure water in the fracturing hole can flow out through the two-way safety valve, which realizes the in-situ pressure maintenance and relief of the hole sealer, ensures that the high-pressure rubber expansion hose is not easy to pop out of the drilling hole, avoids high-speed friction with the fracturing hole, and has a long service life.

Description

technical field [0001] The invention belongs to the technical field of coal-rock layer fracturing, sealing, hole-sealing, and pressure-relieving, in particular to a high-pressure sealing and pressure-relieving protection method for coal and rock layers. Background technique [0002] Accidents such as gas ejection, coal and gas outburst, gas explosion, and rock burst occur frequently in China. Coal rock water injection, coal rock hydraulic fracturing and other technologies are effective means to prevent 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 seal the hole through the expansion of the high-pressure rubber expansion hose and compress the borehole wall. Output, realize high-pressure water injection of coal seam, and stop water injection once the coal s...

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

Images