High Resolution Sequence Stratigraphy Pattern of Putaohua Oil Layer in the East Region of Sanzhao Depression,Songliao Basin

The Putaohua Reservoir in the east region of Sanzhao Depression is connected to the oil and gas resources in Songliao Basin.Due to the inconsistency about stratigraphic correlation and classification of Putaohua oil layer in the east region of Sanzhao Depression,the precise high frequency sequence identification and classification of the reservoir are needed.And a union stratigraphic framework is established.Based on eight well cores and logging and seismic data of 1700 wells,according to the theory of high-resolution sequence stratigraphy sedimentary,the Putaohua oil layer in the east region of Sanzhao Depression is studied.The interface and characteristics of each grade base level cycle in the east region of Sanzhao Depression,Songliao Basin is systematically analyzed.The oil layer is divided into two medium-term base level cycles and nine short-term base level cycles.On the basis of the analysis on the structural type of short term base level cycles sequence,the development pattern of the Putaohua oil layer in the above area is explored.The stratigraphic model is that the thickness of the formation becomes thin toward the south.The top of the Putaohua oil layer moves up,the bottom of that moves down,and each layer is gradually thinning.It is opposed to the new framework of sequences with the absence of central layer or the bottom.The formation development pattern is that the transition point of the medium-term base level cycle is located at the center of SSC 4.There is a decreased half-cycle below the transition point,and an increased half-cycle above the transition point.In addition,a high resolution sequence stratigraphic framework is established.The framework unifies the study area with the Sanzhao depression,providing the solid geological basis for the sandstone distribution,establishment of distribution pattern of reservoir,the cause identification of mainly monosandbody,and potential oil field further tapping.