ANALYSIS OF RESERVOIR FORMATION PERIODS, THE JIANGLING DEPRESSION OF THE JIANGHAN BASIN

Based on the guidance of petroleum system theory and oil-source rock correlation, there are 2 known petroleum systems in Jiangling Depression: upper Shashi formation-lower Xinggouzhui formation and Qian-jiang formation. The major period of reservoir formation for the former one was in the time of sedimentation of Qianjiang-Jinghezhen Formation, after which, it was modified. The petroleum system is characterized by multiple horizons of contemporaneously formed reservoirs because the extensively developed faults act as the important pass in hydrocarbon transmission system. Therefore, the exploration strategy in the depression should be focused on both the primary and the secondary hydrocarbon reservoirs and pay some attention to the upper Xinggouzhui formation, Jingsha formation, Qianjiang formation. Qianjiang formation petroleum system belongs to immature-premature petroleum system, which should be the new exploration area.