Conventional–Unconventional Hydrocarbon Accumulation Within a Tectonically Reworked Whole Petroleum System: Insights from the Kuqa Depression, Tarim Basin, NW China

Understanding hydrocarbon accumulation in deep and ultra-deep tectonically active basins demands an integrated evaluation of conventional and unconventional petroleum systems. The Kuqa Depression, a gas-prone foreland basin along the northern margin of the Tarim Basin, serves as an ideal case for investigating hydrocarbon enrichment mechanisms within a tectonically reworked Whole Petroleum System. Through burial and thermal history reconstruction, structural analysis, and petroleum-system evaluation, this study elucidates the evolution of hydrocarbon generation, redistribution, and retention. The results reveal that rapid Neogene-Quaternary burial accelerated the maturation of Triassic–Jurassic source rocks, triggering concentrated gas generation and widespread overpressure development. Successive foreland deformation has persistently modified reservoirs, migration pathways, and trap geometries, resulting in large-scale hydrocarbon redistribution via fault–fracture networks. Conventional and unconventional accumulations share common source kitchens, burial histories, pressure systems, and tectonic controls, but differ in hydrocarbon retention mechanisms. Conventional accumulations are dominated by migration processes, whereas unconventional accumulations are governed by retention processes. A generation–redistribution–retention framework is proposed to explain hydrocarbon enrichment within a tectonically reworked Whole Petroleum System. This framework provides a unified interpretation of conventional–unconventional hydrocarbon accumulation in the Kuqa Depression and offers insights for deep and ultra-deep petroleum exploration in tectonically active basins.