Research on New Flexible Paste Borehole Sealing Material for Gas Drainage Drilling

In order to improve the borehole sealing effect of the gas extraction drilling, a new flexible paste borehole sealing material was developed.The flexible paste materials, PD materials, expansive cement was tested with viscosity, expansion, permeability, the results showed that the flexible paste materials were superior to PD materials and expansive cement on the three parameters. Aiming at the characteristics that flexible paste had no solidification and good permeability, the continuous grouting borehole sealing process with the gravity loading was developed. Flexible paste materials and grouting borehole sealing technique by gravity was applied in No.13 Coal Mine of Pingdingshan Coal Industry. Compared with the traditional borehole sealing materials and sealing borehole process, the gas concentration of extraction borehole increased from 7.2% to 32% on average.