松辽盆地梨树断陷白垩系沙河子组二段下亚段细粒沉积岩岩相特征及沉积演化OACHSSCD

Shahezi Formation in Lishu Depression is rich in organic matter,high in thermal evolution,and has a solid material basis for shale gas development,with huge resource potential.Based on the comprehensive use of logging data,core and thin section data,organic and inorganic test data,the study analyzes core data from the Lishu Fault,and investigates sedimentary characteristics of fine-grained sedimentary rocks in the lower second member of Shahezi Formation in Lishu Fault Depression.The results indicate:There are eight lithofacies types have been identified in the lower second member of Shahezi Formation in Lishu Fault Depression:massive volcanic breccia,massive medium to coarse-grained tuff,massive biotite tuff,massive tuffaceous mudstone,laminated tuffaceous shale,laminated carbonate-tuff mixed fine-grained rock,mesoscopic tuff and laminated carbonate.The lithofacies characteristics,vertical distribution,and spatial distribution of these lithofacies were characterized.Combining the research results on the petrography of the profiles,planar phases and the main control factors of deposition,a volcanic-lacustrine deposition model under the control of volcanism is established,which provides new ideas for future shale oil exploration and development.