Identification and Characterization of Development Patterns of Deep‐Buried Canyon‐Type Paleokarst Caves in the Northern Tarim Basin: Implications for Carbonate Reservoir Exploration

ABSTRACT The Tarim Basin represents the largest petroliferous basin in China, where paleokarst fracture‐cave systems developed in Ordovician marine carbonate rocks serve as the dominant reservoir spaces for hydrocarbon accumulation. The Tahe Oilfield, located on the northern tectonic uplift of the basin, hosts the most typical and well‐developed examples of this reservoir type. Using high‐resolution 3D seismic data, we reconstructed the paleokarst geomorphology of the Early Hercynian karstification episode—the primary stage governing the formation of Ordovician carbonate fracture‐cave reservoirs in the main eastern block of the Tahe Oilfield. Reconstruction results show that the study area forms an interfluve flanked by river valleys to the east and west, with karst canyons in its eastern sector attaining depths of up to 100 m. Seismic anomalous bodies within the study area were delineated via 3D seismic volume carving technology. Building on this, we applied the uniformitarian principle (the present is the key to the past) to identify these anomalous bodies and interpret their karst hydrogeological implications, drawing on cave development patterns documented in plateau canyon‐type karst terrain of Guizhou Province, southwest China. The proposed identification workflow is illustrated with two typical cases: fracture‐cave systems in the epikarst zone, and peak‐cluster through caves in the vertical vadose zone. Genetically, the paleokarst caves in the study area fall into three major categories. Hydrodynamic conditions are confirmed as the primary controlling factor governing cave development. A thorough elucidation of the formation mechanisms of epigenic paleocaves in deep to ultra‐deep carbonate fracture‐cave reservoirs can only be achieved by grounding analysis in fundamental karst hydrogeological conditions.