Lithologic reservoirs and the control factors of reservoir forming in Ciyutuo structural belt

In order to ascertain the type of lithologic reservoirs and reservoir forming's main control factors in Ciyutuo structural belt,by means of drilling data and lithosome inversion identification,we came to a conclusion that oil-bearing series in Ciyutuo structural belt mainly accumulate in sha-3 member and sha-1 member in Shahejie group.The type of lithologic reservoirs in Ciyutuo structural belt includes sand lens reservoirs,updip pinchouting sand reservoirs and fault lithology reservoirs.The main control factors of lithologic reservoir formation are abundance of oil sources,slope background,main faults,favorable sedimentary facies belt.The accumulation periods of oil are Dongying stage and Taoguan stage.There are two accumulation models.One model is that oil and gas is generated by dark mudstone in lower middle sha-3 member in Niuju-Changtan depression migrates into Ciyutuo high barrier zone along Cidong fault,and upward migrates into appropriate traps along sand reservoirs and plane of unconformity,and then accumulated.The other is that oil and gas migrates into the upper part of overlying sha-3 member,sha-1member,sha-2 member and Dongying group reservoirs along the faults in Niuju-Changtan Depression,a part of the oil and gas is accumulated in Niuju-Qinglongtai structure,and others didn't stop migrating along the sand bodies until it comes to Ciyutuo high barrier zone across the faults,and accumulated.