煤层气储层三维渗透率变化规律实验研究

煤层气开发过程中，储层的渗透性是制约煤层气开发的重要因素之一。采用煤心室内流动实验的方法，对不同围压、不同流压下的煤心进行渗透率测试，得出其渗透率变化曲线；进而，对实验数据进行回归发现，煤心渗透率与围压之间存在幂指数关系，而模型参数与注入压差之间存在指数关系。分析三维渗透率流动实验过程得出，煤心渗透率变化为非可逆过程，煤心的左右方向对压力变化更为敏感；同时，在低压区，渗透率变化较快，而高压区变化平缓。因此，在煤层气开发过程中，要尤其注重低压区压力变化对渗透率的影响。 

Experimental research on variation pattern of 3D permeability in coalbed methane reservoir

During coalbed methane development, the permeability of reservoir is one of the important restricting factors. The paper, adopting lab flowing test of coal cores, has measured the permeability of coal cores under different confining pressure and different flowing pressure, obtained the variation curves of permeability. Furthermore from regression of test data, it was found that there was power exponent relation between the permeability and the ambient pressure in coal cores, and there existed exponential relation between model parameters and injection pressure difference. The analysis of flowing experiment process of 3D permeability indicated that the permeability variation of coal cores is a non-reversible process, the left direction and the right direction of coal cores are more sensible to pressure change. Moreover, in the lower pressure area, permeability change is faster, but in higher pressure area, it is slower. So it should take more attention to the pressure change in the low pressure area during coalbed methane development.