纹层型页岩储层微观孔隙结构对层间窜流的影响规律OA

Laminated structures are extensively present in China's continental shale reservoirs.As a key characteristic for laminated structures,the crossflow between lamellae plays a crucial role in promoting the mobilization of fluids in low-permeability layers.Different types of lamellae display variations in mineral composition and pore structure,which significantly influence the flow both within and between the lamellae.However,due to limitations in research scale,conventional experimental and simulation methods have difficulty in precisely characterizing the pore structure and crossflow features of lamellae.In this study,pore network modeling was employed to construct lamella models with different microstructural parameters,and the elastic depletion flow process of shale oil was simulated.The impact of pore-throat size and pore connectivity in clay and felsic lamellae on crossflow was investigated.The results demonstrate that compared to dispersed and clustered structures,laminated structures exhibit higher fluid production efficiency.The crossflow from clay lamellae with poorer petrophysical properties to felsic lamellae with better properties significantly enhances the mobilization of oil within the clay lamellae.As the pore-throat diameter of the clay and felsic lamellae increases,or pore connectivity improves,the depletion of pore pressure accelerates,and the crossflow rate becomes higher.The proportion of crossflow production volume to the total production volume of clay lamellae is mainly determined by the interlayer permeability ratio.When the interlayer permeability ratio ranges from 100 to 2 000,the proportion of interlayer flow volume is between 80%and 93%.