穿含水层下向钻孔瓦斯压力测定技术研究

Study on Gas Pressure Measuring Technology with Downward Borehole Drilling Through Aquifer

针对赵庄煤矿8-1煤层下向瓦斯测压钻孔穿越2层灰岩含水层时,围岩松软、易破碎、易垮落,难以成孔,真实煤层瓦斯压力难以测定,通过分析穿含水层钻孔各封孔方法的适用条件,结合赵庄煤矿实际地质条件,在同一测压地点布置2个测压钻孔,1号钻孔采用全孔注浆-二次扫孔-注浆封孔方法进行封孔测压,结果未能成功堵水,测得水压0.98 MPa;2号钻孔采用双套管带压注浆封孔方法进行封孔测压,经试验,该方法较好地封堵了含水层裂隙、支固松软围岩,准确测得8-1煤层原始瓦斯压力为0.40 MPa。

According to the soft surrounding rock, easy broken, easy falling, hard to successfully measure the real seam gas pressure, when the downward pressure measuring borehole in No. 8^-1 seam of Zhaozhuang Mine passed through two limestone aquifers, with the analysis on the suitable conditions of each borehole sealing method for the borehole through the aquifers,in combination with the actual geological con- ditions of Zhaozhuang Mine,two pressure measuring boreholes were set at the same pressure measuring place. No. 1 borehole was tested with the full borehole grouting-secondary borehole cleaning-grouting borehole sealing method for borehole sealing and pressure measure- merit.The results were not successful to seal the horehole and the water pressure measured was 0.98 MPa.The borehole sealed and pressure measuring of No. 2 borehole was conducted with the double casing pipe and pressurized grouting borehole sealing method.After the test, the method could well to seal the cracks of the aquifer, support and reinforce the soft surrounding rocks and the in-situ gas pressure value of No. 8^-1 seam accurately measured was 0.40 MPa.