Study on Sedimentary Facies Types and Sand Body Configuration of Triassic TI Layer in the Sangtamu Area, Tarim Basin, and Northwest China

The complexity of internal architecture within thick sandstone bodies is a key geological factor controlling fluid distribution in reservoirs and influencing hydrocarbon recovery efficiency. To investigate the strong sandbody heterogeneity and complex fluid distribution in the Sangtamu area of the Tabei uplift, Tarim basin, this study focuses on the Triassic TI sublayer. Integrated analysis of core observations, well‐logging data, and 3D seismic data confirms the TI sublayer as a braided fluvial depositional system. Based on the spatial distribution patterns of fourth‐order architectural units within this braided fluvial reservoir, a detailed reservoir characterization study was conducted: identifying individual channel stories within single wells utilizing calcareous and argillaceous interbeds, delineating single‐phase braided channel belts using a well‐to‐well correlation method constrained by paleotopographic elevation, and systematically dissecting the internal architectural characteristics of the amalgamated sand body according to a hierarchical framework (braided channel belt, single channel, internal architectural elements within a single channel). Results shows that, lateral migration of channels resulted in the stacking of sandstone body from different layers. Within coeval channel belts, architectural boundaries between different single channels, as well as between mid‐channel bar sand body and channel‐fill sandstone body within individual channels, impeded sandbody connectivity (resulting in incomplete connectivity). This research effectively clarified the oil–water distribution relationships and resolved static geological conflicts within the study area, providing a robust geological basis for optimizing field development plans and enhancing hydrocarbon recovery.