太阳集团网tyc9728(百度)有限公司

Abstract: The Longmaxi Formation shale in the Sichuan Basin has been affected by late-stage tectonic uplift, leading to significant differences in the pore structures of reservoir formations across various structural units and burial depths in development wells. These differences result in variations in gas content and saturation, leading to noticeable disparities in development performance and issues such as unstable production. Therefore, understanding the rebound adjustment mechanisms of pore structures in shale reservoirs is a key scientific question for uncovering the dynamic adjustment and accumulation mechanisms of shale gas. This study employs high-pressure triaxial creep experiments combined with scanning electron microscopy and fractal theory to qualitatively and quantitatively characterize various pore structures in the organic-rich shale of the Longmaxi Formation, disclosing the mechanisms and patterns of rebound response of various pore types. The results indicate that as creep pressure decreases, the rebound adjustment patterns vary among pore types. The complexity and distribution of organic matter pores initially increase and then decrease, while intergranular pores exhibit a trend of first decreasing and then increasing. Furthermore, based on microscopic evolution and changes in fractal dimension characteristics, shale pore rebound adjustment mechanisms can be broadly classified into two types: the plastic and brittle rebound adjustment pathway. This study combines theoretical analysis with experimental results to develop rebound adjustment models and response mechanisms for different pore types. This approach is essential for explaining how late-stage tectonic uplift during geological history regulates dynamic changes in shale pore structures and the process of shale gas accumulation.