Tectonic–Sedimentary Differentiation of Cratonic Basins in China and Its Controlling Effects on the Development of Large-Scale Carbonate Reservoirs

Abstract The Tarim, Yangtze, and North China cratons in China are characterized by small scales, poor tectonic stability, and strong tectonic–sedimentary differentiation. Based on the investigations of the prototypes and paleogeographical evolution of the Tarim, Sichuan, and Ordos Basins, this study classified tectonic–sedimentary differentiation and analyzed its controlling effects on large-scale reservoirs. In this study, the main factors controlling the development of three types of large reservoirs, i.e., the reef-shoal reservoirs of the Sinian Dengying Formation in the Sichuan Basin, the intraplatform grain shoal reservoirs of the Cambrian Longwangmiao Formation and the Xixiangchi Group, and the Ordovician paleokarst reservoirs in the Tabei paleo-uplift in the Tarim Basin, were analyzed. Based on the analytical results, this study summarized the controlling mechanisms of tectonic–sedimentary differentiation on the development of large-scale reservoirs and obtained the following conclusions: (1) The orderly superimposition of rift basins, basins with passive continental margins, cratonic depression basins, and foreland basins in the extensional‒convergent tectonic cycles of marine basins controls the regular development of reef-shoal reservoirs, intraplatform grain shoal reservoirs, and paleokarst reservoirs. (2) The development of reef-shoal reservoirs is controlled by the formation of intracratonic and marginal rifts in a strong extensional setting, whereas the development of intraplatform grain shoal reservoirs is controlled by the formation of intracratonic depressions in a weak extensional–weak compression setting, and the development of karst reservoirs is controlled by paleo-uplifts that formed during the strong compression period. (3) The development of high-quality reservoirs in the Sinian Dengying Formation and the Cambrian Longwangmiao Formation and Xixiangchi Group in the Sichuan Basin was controlled by high-energy facies belts, early dolomitization, and early karstification. High-quality reservoirs show a zonal distribution under strong tectonic differentiation and a planar discontinuous distribution under weak tectonic differentiation. (4) The development of Ordovician karst in the Tabei paleo-uplift of the Tarim Basin was controlled by the lithology of the parent rocks, paleoclimate, tectonic landforms, and exposure time. Karst reservoirs are distributed in the form of rings under tectonic differentiation.