Formation mechanism and reservoir quality evaluation in tight sandstones under a compressional tectonic setting: the Jurassic Ahe Formation in Kuqa Depression, Tarim Basin, China

作者：Dong Li, Guiwen Wang, Kang Bie, Jin Lai, Dewen Lei, Song Wang, Hai-Hua Qiu, Hongbo Guo, Fei Zhao, Xing Zhao, Qi-Xuan Fan · 发表于：Petroleum Science · 年份：2024 · DOI：10.1016/j.petsci.2024.12.026 · 被引用次数：14 · 研究领域：Hydrocarbon exploration and reservoir analysis、Hydraulic Fracturing and Reservoir Analysis、Geological Studies and Exploration

The northern structural belt of Kuqa Depression is adjacent to the South Tianshan orogenic belt, which are characterized by complex geological conditions. The reservoir quality of the Jurassic Ahe Formation is controlled by sedimentation, diagenesis, and tectonics, and show complex pore structure and strong heterogeneity, thereby hindering effective natural gas exploration and development. Core, thin sections, cathodoluminescence (CL), scanning electron microscopy (SEM), conventional well logs and image logs are used to characterize the petrological characteristics and pore systems. Then a comprehensive analysis integrating sedimentation, diagenesis, and tectonics is performed to unravel the reservoir formation mechanism and distribution of reservoir quality. Results show that reservoir properties are generally environmentally selective. Coarse grained sandbodies (gravelly sandstones) formed in high depositional-energy have the best physical properties, while fine sandstone and mudstone with low depositional energy is easily to be tightly compacted, and have poor reservoir quality. Porosity usually decreases with compaction and cementation, and increases due to dissolution. Clay minerals filling pores result in a deterioration of the pore structure. Microfracture formed by fracturing can connect the matrix pores, effectively improving the reservoirs’ permeability. The differential distribution of fractures and in-situ stress plays an important role in modifying reservoir qual...