| In view of the single implementation of the soft low-breathable coal seam-based hydraulic punch enhancement measures,and the lack of comprehensive strengthening measures,a research experiment was carried out on the pressure-based drilling hydraulic punch injection gas injection test in Xin’an Coal Mine.Through theoretical analysis,numerical simulation,field test and tracking,the effect struck on improving the breathability and gas extraction effect of coal seam steaming and gas extraction was studied under different conditions.This paper has carried out research in the following areas:(1)The mechanism of hydraulic punching and pumping is analyzed,according to the characteristics of injecting gas into the coal seam after hydraulic punching to diffuse to the coal micropores,and to analyze the mechanism of intensive extraction under the action of gas injection around hydraulic punching.(2)Introduce the technical process of hydraulic punch ingesting gas repellent to strengthen extraction,standardize the technical measures of hydraulic punch safety,and ensure the smooth and reliable development of hydraulic punch ingesting gas extraction test through perfect process and safety technical measures.(3)A numerical simulation of hydraulic punching under different coal-out coal conditions is carried out.Using the change law of gas pressure after Comsol Multiphysics simulation punch,it is concluded that when the amount of coal is expanded at a certain time,the effective influence radius of extraction increases gradually with the extension of extraction time,but the percentage of the effective impact radius increases by the equivalent increase increase is smaller and smaller,and the rate of reduction is smaller than that of ordinary drilling,the effect of increasing the expansion of coal is decreasing;The effective influence radius of extraction increases gradually with the increase of coal out,but when the amount of coal is increased to a certain extent,the increase of the effective influence radius of extraction decreases.(4)For the soft low breathable coal seam applicable to the “hydraulic punch ingestive and injection gas drive” comprehensive deepening extraction measures to study,the technical step is the first hydraulic punching,after the hydraulic punch drilling gas concentration flow attenuation,to investigate the single-hole extraction flow,gas concentration and other parameters change law,to obtain the continuous deepening pumping of coal seams,help to achieve high-efficiency coal seam.Through the above research,this paper expounds the process of hydro-punch injection gas extraction to strengthen extraction technology,and determines the key technical parameters such as the reasonable coal injection of the hydraulic punch of Xin’an Coal Mine with a reasonable amount of 1.0t/m,the reasonable extraction time of90 days,and the effective influence radius of extraction of 3 metres. |
PDF Full Text Request