天然气工业2017，Vol.37Issue(11)：53-60,8.DOI:10.3787/j.issn.1000-0976.2017.11.007
实际状态下的页岩气表观渗透率计算新模型
A new model for calculating the apparent permeability of shale gas in the real state
摘要
Abstract
In all the existing apparent permeability calculation models used for shale gas,the effect of surface diffusion of adsorbed gas is neglected and shale gas is assumed to be in an ideal state,so the calculation results may not reflect the real situations.In this paper,a new apparent permeability model suitable for the shale gas of real state was developed by seepage mechanics method.In this model,the influential factors (e.g.the viscous flow and Knudsen diffusion of free gas and the surface diffusion of adsorbed gas) are taken into account to present the real flowing situations of shale gas in nanopores.Then,the accuracy of this new apparent permeability model was verified by comparing its calculation results with the experimental data.Finally,all factors influencing the apparent permeability of shale gas were analyzed in this new model.It is shown that the apparent permeability of shale gas is most affected by pressure and pore radius,and less by relative molecular mass and blockage coefficient.Langmuir maximum adsorption capacity,Langmuir pressure and isosteric adsorption heat mainly affect the fraction of permeability contributed by surface diffusion.Besides,the effects of each factor on apparent permeability and permeability fraction under low pressure are different from those under high pressure.Under low pressure,the effects of temperature and pore radius on apparent permeability are more obvious,and the effects of temperature,pore radius,Langmuir maximum adsorption capacity,Langmuir pressure and isosteric adsorption heat on the fraction of permeability are also more obvious.Finally,when the pressure is low and the pore radius is small,the surface diffusion is dominant.When the pressure is high and the pore radius is large,the viscous flow is dominant.In the case of small pore radius or low pressure,the surface diffusion shall not be neglected.关键词
实际状态/页岩气/表观渗透率/计算模型/黏滞流/Knudsen扩散/吸附/表面扩散/渗透率比重Key words
Apparent permeability of shale gas in actual state/Computation model/Viscous flow/Knudsen diffusion/Adsorption/Surface diffusion/Fraction of permeability引用本文复制引用
张艳玉,李冬冬,孙晓飞,宋兆尧,石达友,苏玉亮..实际状态下的页岩气表观渗透率计算新模型[J].天然气工业,2017,37(11):53-60,8.基金项目
国家科技重大专项“鄂南长7页岩油流动机理及数值模拟技术研究”(编号:2017ZX05049-006)、国家自然科学基金项目“页岩油多尺度运移机制及数值模拟”(编号:51674279). （编号:2017ZX05049-006）
