Abstract:

The oil and gas pools of the Lower Jurassic Daanzhai and Lianggaoshan Formations in central Sichuan are distributed in semi-deep lake and shallow lake facies.The east partis similar to Central Sichuan in this respect.They are two symmetric parts of the same fa-cies zone deposited in the same lake basin.The difference is that exploration level is verylow in East Sichuan.The reservoir beds in the above regions are compact lenticular shell-limestone and sandstone formed by shelly beaches,sand barries and sandbars.Fracturesare well developed in the reservoir beds,formed fracture-lithologic reservoirs.Though thisregion is intensively folded and seriously denuded,the Jurassic reservoir beds inwide-gentle synclines separated from high-steep anticline zones are well preserved.Amongthem,lower and gentle structures,buried structures,the axes of synclines,the affectedzones in the upper end of buried overthrusts and flexural zones are all favourable places toseek for fracture-lithologic trapped hydrocarbon pools.