Shale gas reservoirs have low original water saturation, mostly as irreducible water. Based on the microscopic forces between the liquid and solid surfaces, this paper presents a method for calculating the thickness of water films in different inorganic pores in shale. The water film distribution at different water saturations in the inorganic matter is obtained, considering the multi-shaped pores in inorganic matter. Using the calculated water film distribution, the gas storage and transport capacity at different water saturations are studied, considering gas migration mechanisms in microscale pores and the characteristics of inorganic matter. Models for the apparent porosity and permeability model of inorganic matter with water film are proposed. The effects of water saturation on apparent porosity and permeability of inorganic matter were analyzed. The results showed that with an increase in water saturation, apparent porosity decreases greatly. The gas storage of reservoirs in which the water saturation is 0.20 is about 25% lower than that without water film. When the water saturation increased from 0 to 0.20, the apparent permeability decreased by about 40%.

中文翻译：

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页岩气藏水膜无机物的视孔隙率和渗透率模型

页岩气储层的原始水饱和度低，主要是不可还原水。基于液体和固体表面之间的微观力，本文提出了一种计算页岩不同无机孔隙中水膜厚度的方法。考虑到无机物中的多形孔隙，获得了无机物中不同水饱和度下的水膜分布。利用计算出的水膜分布，考虑了微尺度孔隙中的气体运移机理和无机物的特征，研究了不同含水饱和度条件下的储气和输运能力。提出了水膜无机物的表观孔隙率和渗透率模型。分析了水饱和度对表观孔隙率和无机物渗透率的影响。结果表明，随着含水饱和度的增加，表观孔隙率大大降低。水饱和度为0.20的储层的储气量比没有水膜的储气层低约25％。当水饱和度从0增加到0.20时，表观渗透率降低了约40％。