论文部分内容阅读
为了解决复杂环境下立井揭煤前煤层瓦斯压力的可靠测定,基于揭煤井筒瓦斯地质特征、煤岩体物理力学性质,应用COMSOL软件模拟揭煤工作面在接近目标煤层时,井筒周围煤岩的地应力分布特征,直观展现了目标煤层中的应力分布结果。模拟结果表明,立井工作面距煤层的垂直距离为7 m时,煤层中会形成一个近似于环形的卸压圈,卸压半径为16 m,因此煤层瓦斯压力测试孔的终孔位置应布置在井筒中心线16 m以外的原始地应力区,以保证测压点瓦斯压力不受揭煤井筒卸压区的影响,令测压结果准确可靠,从而更好地预测煤与瓦斯突出区域的危险性。同时,结合立井揭煤工作面的水文地质特征和井筒严重淋水情况,自主研发并应用了瓦斯测压孔“两堵一注”封孔材料及特定的封孔工艺,进一步保障了封孔质量和瓦斯压力测试结果的可靠性。最后,依据测压结束时测压管内的实际水压情况,对测压结果进行修正,并依据实测瓦斯含量,采用间接法对所测得的瓦斯压力进行验证,实测值在反算得到的瓦斯压力值域内,表明此方法有效可行。
In order to solve the reliable determination of coal gas pressure before shaft uncovering coal in complicated environment, based on the gas geological characteristics of coal seam borehole and the physical and mechanical properties of coal and rock mass, COMSOL software was used to simulate the coal and rock surrounding the wellbore near the target coal seam The distribution of geostress shows the stress distribution in the target coal seam. The simulation results show that when the vertical distance between vertical working face and coal seam is 7 m, an annular relief ring is formed in the coal seam with a pressure relief radius of 16 m. Therefore, the final hole position of gas pressure test hole in coal seam should be arranged at The original stress zone beyond 16 m of the wellbore center line ensures that the gas pressure at the pressure measuring point is not affected by the pressure relief zone of the coal exposing wellbore and the pressure measurement results are accurate and reliable so as to better predict the danger of coal and gas outburst areas . At the same time, combined with the hydrogeological characteristics of vertical coal uncovering coal face and the severe water loss in wellbore, independent research and development and application of gas pressure measuring hole, “two holes and one injection” sealing material and specific sealing technology further protect the seal Hole quality and reliability of gas pressure test results. Finally, the pressure measurement results are corrected according to the actual water pressure in the piezometer at the end of the pressure measurement, and the measured gas pressure is verified by the indirect method according to the measured gas content. The measured value of the gas Pressure range, indicating that this method is feasible.