To characterize impacts of diffusion, stress sensitivity, matrix shrinkageand adsorption layer on shale gas permeability, weighting coefficient coupled transitional diffusionand Knudsen diffusion have been deployed to construct the mathematic modelfor diffusion permeability.Relevant tests have been performed to verify the model.At the same time, impacts of matrix shrinkage, stress sensitivity and thicknesses of shale gas adsorption layers with different pore diameters on permeability have been reviewed.Research results show the proposed shale gas permeability model can effectively characterize diffusion in different transmission stages to eliminate problems related to higher permeability induced by using Knudsen diffusion alone.It can be seen that the newly-constructed model can better describe shale gas transmission under impacts of multiple physical fields.Relevant research results may provide valuable guidance for shale gasdevelopment.%为表征扩散、应力敏感、基质收缩和吸附层对页岩气渗透率的影响,通过加权系数耦合过渡扩散和努森扩散,建立了扩散渗透率数学模型,并通过实验进行验证,同时分析了基质收缩、应力敏感、不同孔径页岩气吸附层厚度对渗透率的影响.研究结果表明,建立的页岩气渗透率模型可以有效表征不同传输阶段的扩散,避免了单独使用努森扩散所带来的渗透率偏大等问题,可以更全面地描述多物理场影响的页岩气传输.该研究成果对页岩气的开发具有一定的借鉴意义.
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