Unlike marine shales， lacustrine shale sequence in China exhibits intricate source rock-reservoir configuration and coupling relationships， as well as significantly different storage characteristics between shales and their interbeds. Therefore， it is necessary to ascertain the evolutionary patterns of shales and their interbeds， which will provide critical guidance on the exploration of lacustrine shale oil and gas. Using data on mineral compositions， organic geochemistry， and physical properties， as well as data from the analyses and observations of cores， thin sections， and scanning electron microscopy （SEM） images， we conduct a comprehensive study of the lacustrine shales in the Triassic Yanchang Formation of the Ordos Basin， the Jurassic Ziliujing Formation of the Sichuan Basin， and the Cretaceous Yingcheng Formation of the Songliao Basin， which vary in thermal evolution. By analyzing the storage space types and physical properties of shales and their interbeds in these formations， we explore the formation and evolutionary processes of pores in both shales and their interbeds and establish differential evolutionary patterns of the pores. The results are as follows： （1） The lacustrine shales in China are of diverse lithofacies types， primarily consisting of mixed， clayey， and silty shales， which tend to alternate with carbonate， sandstone， and tuff， suggesting complex lithofacies assemblages. The storage spaces in the shales are dominated by inorganic pores， followed by organic pores， with microfractures developed locally. In contrast， the storage spaces in the interbeds are dominated by inorganic pores such as residual intergranular （dissolved） pores， intragranular （dissolved） pores， and microfractures； （2） The evolution of pores in the lacustrine shales and their interbeds is influenced by both diagenesis and hydrocarbon generation. The shales， with high clay content and weak anti-compaction capacity， undergo a rapid decrease in inorganic pores before hydrocarbon generation. After entering the oil generation window， these shales experience a gradual increase in organic pores， clayey intergranular/intercrystalline pores， dissolved pores， and microfractures. Prior to the late diagenetic stage， the shale porosity tends to decrease before the peak oil generation and increase afterward. In contrast， the interbeds become increasingly tight under compaction and cementation， leading to a gradual decrease in their storage capacity； （3） The Yanchang Formation shale in the oil generation window， contains underdeveloped organic pores and thus exhibits poor storage capacity. In contrast， the sandstone interbeds in the formation present more favorable shale oil enrichment conditions. The Ziliujing Formation in the mature to highly mature stage， exhibits oil and gas coexistence， characterized by well-developed organic and inorganic pores in the shale， more favorable for storage， while the interbeds serve as secondary reservoirs or barriers. The Yingcheng Formation in the highly mature to overmature stage， is the most favorable for the formation of shale gas and organic pores， boasting the optimal storage conditions in shales.
