Hydrocarbon migration system and accumulation evolution in Paleozoic, Katake Uplift, Tarim Basin

Rich petroleum resources have been found in Paleozoic of the Katake Uplift,the Tarim Basin.Influenced by multiple stages of tectonic evolution,the study area is characterized by the following complicated accumulation features such as mixed hydrocarbon sources,early oil charging,late gas charging,3 stages of accumulation,and multiple accumulations.The complicated accumulation processes restrict the studies of accumulation principles.Based on studies of the main controlling factors for hydrocarbon accumulations in the region,the hydrocarbon migration system has been divided into 3 big types:fracture,unconformity and reservoir body.4 models for space combination are also discussed.From the aspect of source fracture and region unconformity evolution,the relationship between hydrocarbon migration system evolution and hydrocarbon generation and charging during the 3 key stages for accumulation (late Caledonian-early Hercynian,late Hercynian and Himalayan) are talked about.The regional hydrocarbon source faults such as Tazhong I and II as well as the NE oriented strike-slip faults work as the main pathways for vertical migration.In uplifting and slope regions,T₆⁰,T₇⁰,and T₇⁴ unconformities work together with matrix sandbodies of the Donghetang Formation,providing horizontal pathways for migration.The spatial distribution of karst network and inherited trap controls the favorable direction and accumulation position for hydrocarbon.In the Katake Uplift,the most outstanding feature for accumulation evolution is the cooperation of multiple migration systems composed of fracture,karst and unconformity,resulting in multiple stages of hydrocarbon charging and adjusting in 3 dimensions.