页岩储层气体流动能力实验研究

Gas Flow Capacity Experiment in Shale Reservoir

针对采用常规渗透率无法有效表征页岩储层流动能力的现状,运用自主研发的页岩气稳态流动和衰竭开发物理模拟实验装置,测试了压力为0. 0~30. 0 MPa的气体流动能力,结合孔隙分布和应力敏感测试,建立了页岩储层基质气体流动能力的表征方法。研究表明:页岩储层中气体流态以滑脱流为主,明确了滑脱因子、吸附以及应力敏感对流动能力的影响,建立了氦气渗透率、氮气渗透率与甲烷渗透率三者之间的转换关系;建立了考虑滑脱、吸附和应力敏感的表观渗透率模型,能表征页岩气在基质中的流动能力。建立的表观渗透率模型更接近原始储层气体的真实流动状态,能反应页岩气开发过程中储层的实际渗流能力,从而为页岩产气规律评价和生产动态预测提供科学依据。

In order to effectively characterize the flow capacity of shale reservoir that cannot be accurately characterized by conventional permeability,the self-developed shale gas steady flow and depletion development simulation experiment devices were used to test the gas flow capacity under the pressure of 0 ~ 30 MPa. A flow capacity characterization method for shale reservoir matrix system was established by combining with the pore size distribution and stress sensitivity test. Research indicates that the gas flow in the shale reservoir is dominated by slip-off flow,which clarified the effects of slip factor,adsorption and stress sensitivity on the flow capacity. A conversion relationship was established between the helium permeability,nitrogen permeability and methane permeability. An apparent permeability model considering slippage,adsorption and stress sensitivity was established to characterize the gas flow capacity in the shale matrix system. This apparent permeability model with favorable characterization of the true gas flow stage in the formation can accurately represent the actual flow capacity during shale gas development,which could provide certain reference for the shale gas production performance evaluation and forecast.