压降及储层压力与煤变形的相关性研究

为了进一步完善解吸瓦斯煤体变形机理，探讨压降和储层压力对煤解吸瓦斯的影响，采用原煤试件，进行了不同储层压力和压降的煤解吸瓦斯变形实验。实验结果表明，解吸达到平衡所需时间与储层压力及压降呈正相关关系；降压0.3 MPa时，收缩应变随储层压力的增加而减小；降压至大气压时，收缩应变随储层压力的增大而增大，储层压力0.9 MPa的大于储层压力0.6 MPa的大于储层压力0.3 MPa的；当储层压力相同时，收缩应变随压降的增大而增加；当储层压力较小时，大压降储层瓦斯解吸量大于小压降储层瓦斯解吸量。

A Study on the Correlation between the Pressure Drawdown Gradient and Reservoir Pressure and the Coal Deformation

In order to further understand the deformation mechanism of desorbed gas (coalbed methane) coal and to investigate the effects of pressure drawdown gradient and original reservoir pressure on the desorbed gas from coal (coalbed methane), desorbed gas (coalbed methane) coal deformation tests were performed using raw coal samples under different original reservoir pressures and pressure drawdown gradients. The results showed that the time required for desorption to reach equilibrium has a positive correlation with the original reservoir pressure and the pressure drawdown gradient. When the pressure is reduced to 0.3 MPa, the shrinkage strain decreases with an increase in the original reservoir pressure. When the pressure is reduced to atmospheric pressure, the variation in the shrinkage strain with the original reservoir pressure follows the trend that under 0.9 MPa it is higher than that under the 0.6 MPa, which is higher than that under 0.3 MPa. When the original reservoir pressure is the same, the shrinkage strain increases with an increase in the pressure drawdown gradient. When the original reservoir pressure is relatively small, the desorption capacity of the high pressure gradient reservoir is larger than that of the low pressure gradient reservoir.