Abstract:

Different sedimentary filling characters generated by the differences in tectonic evolution and climatic condition between upper and lower member in Shashi Formation，Jianghan Basin.Under weak fault depression tectonic condition and arid subtropical climate during depositional period of the lower member，evaporites were deposited in separated salt-lake and presented a concentrated sedimentary sequence.However，under depression tectonic condition during the depositional period of the upper member，sedimentation of delta-lake facies filled the enlarged basin and presented a desalted sedimentary sequence，which led to different source-reservoir-seal combinations and hydrocarbon accumulation modes.In concentrated sedimentary sequence，evaporate rocks and mudstone within salt-layers provide source condition，the gypsum rocks and mudstone within salt-layers provide reservoir condition，and the evaporate rocks provide seal condition.In desalted sedimentary sequence，mudstone in lacustrine facies and pro-delta micro-facies provide source condition，the different channel sandstone provide reservoir condition，and the evaporite rocks provide seal condition.