Development and Application of a New Self-Expanding and Pressure-Resistant Flower Tube for Gas Extraction
During gas extraction through soft coal seams,under the influence of mining,it is prone to occur borehole shrinkage deformation and collapse,flower tube blockage,and other problems,resulting in low gas extraction efficiency,prolonged extraction cycle,and even the need for additional holes for secondary gas extraction.In order to solve the above problems,a self expanding and pressure-resistant flower tube for hole protection was studied.The spring steel sheet outside the new flower tube expanded into a sphere in the borehole,which can effectively resist the borehole deformation,and the outer steel wire mesh fabric prevented coal collapse and flower tube blockage.Therefore,there was still a large space for gas radial flow and spherical flow between the coal seam and the flower tube in the middle and late stages of extraction,which helped the gas to be transformed from the adsorption state to the free state and improved the gas extraction efficiency.The field test shows that in the early stage of gas extraction,the average gas extraction concentration of the control group using conventional flower tube is close to that of the experimental group using self-expanding flower tube.However,in the middle and late stage after 50 days of extraction,the gas extraction concentration of the experimental group can still be maintained at more than 20％,and the gas emission is more than 4 times that of the control group.Thus,the new self-expanding flower tube has a good application value.
Gas extraction boreholeSelf-expanding flower tubeGas emission amountGas extraction concentrationNumerical simulation
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维普
