Capsule-Bag-Type Sealing Technology for Gas Drainage Boreholes and Its Application

Abstract

In gas control, the quality of drilling and sealing plays a key role in the final effect of gas drainage. This paper first studies the mechanism of hole leakage and the stability of the hole sealing section. At the same time, the bag-type grouting hole sealing device and safety pressure limiting valve were developed, and a new grouting hole sealing method for gas extraction was put forward, which could exert active strong support on the hole sealing section. The grouting cement with a high flow state, early strength, good injection ability, and good microexpansibility was prepared by compounding the fast hard sulfoaluminate cement and ordinary Portland cement and adding the appropriate amount of admixture to stimulate its activity. Engineering practice shows that compared with the polyurethane hole sealing method, 97% of the total holes with gas extraction concentration above 60% are extracted by the new grouting hole sealing method under the same conditions. 47% of the total holes were extracted with a gas concentration above 60% in the polyurethane hole sealing method. This shows that the new grouting hole sealing method can keep the stability of the hole sealing section of the borehole, can evade the leakage channel around the borehole, and is beneficial to gas extraction.