The Diagenesis of Shanxi Group Shale and Its Impact on Pore Development

Abstract

The Shanxi Formation, as a key marine-terrestrial transitional sedimentary stratum of the Permian in North China, exhibits shale porosity characteristics that directly govern its hydrocarbon storage and flow capacity. Diagenesis serves as the core factor regulating porosity evolution. This study focuses on the marine-terrestrial transitional shales of the Shanxi Formation. It systematically reviews the regional geological context, summarizes current domestic and international research on diagenesis and pore development within the formation, and outlines commonly used research methodologies. The analysis emphasizes the positive and negative impacts of major diagenetic processes-including compaction, cementation, dissolution, replacement, and organic matter evolution-on pore development. Utilizing indices such as vitrinite reflectance (Ro), and clay mineral transformation. It concludes by summarizing core findings and existing gaps in current research while proposing future research directions. Research indicates that diagenetic processes in the marine-terrestrial transitional shales of the Shanxi Formation are complex. Compaction and cementation are the primary causes of pore loss, while dissolution and organic matter evolution are key to secondary pore formation. The diagenetic stage primarily ranges from Middle Diagenetic Stage B to Late Diagenetic Stage, with the interaction of various diagenetic processes collectively determining the final pore development characteristics. This study provides theoretical reference and technical support for hydrocarbon exploration, development, and reservoir evaluation in the marine-terrestrial transitional shales of the Shanxi Formation.