雨汪井田超压含煤地层孔隙特征及孔隙体积模量演变规律

煤及煤层气开发中的异常高压现象会对资源开发带来危险,从而威胁到人员和财产的安全.本文选取云南雨汪煤矿的6个煤样,联合CT扫描技术和低温液氮吸附实验方法,分析测试得到超压煤样孔隙半径、孔喉半径、孔容-孔径微分分布的孔隙特征参数;基于Gassmann模型的机理,推导了不同围压条件下的干燥及饱和超压煤样孔隙体积模量.结果表明...

The evolution law of pore characteristics and pore bulk modulus for overpressured coal-bearing formation in Yuwang Minefield

The abnormal high pressure in coal and coalbed methane exploitation will bring danger to exploitation, thus threatening the safety of personnel and property.Six coal samples collected from Yuwang colliery in Yunnan province were analyzed by CT scanning and low-temperature liquid nitrogen adsorption experiment.Analysis reveals the characteristic parameters of pore radius, pore throat radius and pore volume-pore diameter differential distribution of overpressured coal samples.Meanwhile, the pore bulk modulus of overpressured coal samples under different confining pressures is derived based on the mechanism of the Gassmann model.The results show that the porosity of Yuwang colliery overpressured stratum can reach 10 %, and the mesoporous pore shape is mainly spherical and cylindrical.The shear wave velocity of dry coal samples increases nonlinearly with confining pressure.The pore bulk modulus of saturated coal sample remains proportional to confining pressure, but increases rapidly when the water saturation exceeds 90 % with the same confining pressure.