涌水条件下的下向钻孔煤层瓦斯压力测定技术

Measurement technology of coal seam gas pressure in the downward hole under water burst

针对下向涌水钻孔煤层瓦斯压力测定的难点,通过两堵一注的水泥砂浆封孔技术使下向涌水钻孔形成良好的位于裂隙含水层以外的测压气室,较好地封堵裂隙含水层,消除其对瓦斯压力测定的影响。通过对测压钻孔周围瓦斯压力和水压力曲线分布的分析,结合现场封孔测压数据,确保了下向涌水钻孔煤层瓦斯压力测定结果的准确性。

Aiming at the difficulty of measurement of coal seam gas pressure in the downward hole under water burst, hole sealing technology with two blockage and one injection of cement plaster was proposed, which better blocked up the fissured aquifer, furthermore formed the air chamber to gas pres- sure measurement outside of the fissured aquifer in the downward hole under water burst, thus elimina- ted the effect of the fissured aquifer on the gas pressure measurement. The distribution of gas pressure and water pressure around the hole of gas pressure measurement was analyzed, combining with the data of gas pressure measurement in the sealed hole on site, which insures the accuracy of gas pressure meas- urement of coal seam in the downward hole under water burst.