Hydrocarbon pooling conditions of the foothill belt of the Dabashan Mountain and exploration direction
Li Shuangjian1,Zhou Yan2,Gao Bo1,Sun Dongsheng1(1.Exploration and Development Research Institute,Sinopec,Beijing 100083,China;2.Laboratory of Marine Facies and Reservoirs,Sinopec,Beijing 100083,China)
Seismic acquisition and processing are challenging in the foothill belt of the Dabashan Mountain in the marginal area of the Sichuan Basin due to strong tectonic deformation and complex surface seismic geologic conditions,so the exploration maturity is still very low in the study area at present.In order to predict the potential of petroleum exploration,we analyzed the hydrocarbon pooling conditions in this area in respect of source-reservoir-seal combination,source rocks,reservoir and sealing conditions.The original hydrocarbon pooling conditions are favorable and there are 3 plays and various types of exploration pay zones.The analysis of the paleo-reservoir in this study area shows that the major source rocks contributing hydrocarbons to the Permian and Triassic reservoirs in the foothill belt are mainly in the Upper Permian formations,where the hydrocarbon pooling is divided into 3 stages.The first stage is at the Late Triassic-Early Jurassic,when tectonic deformation initiated and paleo-pools were formed in wide and gentle anticlines.The second stage is at the Middle-Jurassic-Early-Cretaceous,when tectonic deformation continued,traps finalized,and crude oil in some palaeo-pools cracked to form oil/gas reservoirs.The third stage is at the Paleogene,when the Himalayan movement strongly transformed the existing traps,which resulted in the adjustment and destruction of the palaeo-pools.The comprehensive analysis of tectonic deformation style,reservoir distribution and oil/gas displaying characteristics reveals that the favorable exploration area is from the Zhenba Fault to the Tiexi-Wuxi buried fault in the northwestern part of South Dabashan Mountain,where the major targets are the Permian Changxing Formation and the Triassic Feixianguan Formation reservoirs of reef-bank facies.In addition,it indicates that preservation conditions of the presalt Cambrian reservoirs should be the focus of research in the southeastern part of South Dabashan Mountain,where the Permian and Triassic are outcropped from the Jimingshi Fault to the Tiexi-Wuxi Fault.
【Fund】： 国家科技重大专项“海相碳酸盐岩大中型油气田分布规律及勘探评价”(编号:2008ZX05005);; 国家重点基础研究发展计划(973计划)“中国早古生代海相碳酸盐岩层系大型油气田形成机理与分布规律”(编号:2011DB214800)
【CateGory Index】： P618.13
【CateGory Index】： P618.13