Source-to-sink System Characteristics And Favorable Reservoir Sandbodies Prediction Of Fulongquan Fault Basin In The Songliao Basin

The Fulongquan fault basin was studied in this paper.The main research contents include sequence stratigraphic framework between Shahezi formation and Quansan member of Quantou formation,source-to-sink system formation models in different sedimentary period and favorable reservoir sandbody distribution,which can provide geological basis for the resource exploration of Fulongquan fault basin.According to the sequence-interface identification marks,the section studied was divided into three second-order sequences and ten third-order ones.The Fulongquan fault basin was manifested as an asymmetrical dustpan-like fault structure,with fault in the east and slope in the west.In different area of the fault basin,the sequence stratigraphy's filled characteristics were different,and it was in general spreading nearly thick in west and thin in east.with the depocenter migrated from south to north because of different boundary fault activity intensities in different periods.Mainly source directions in different periods were distinguished and its system features were studied on the basis of various source analysis methods,which showed that the source system changed from mainly in north-south direction long-axis model and secondarily east-west direction short-axis model to north-south direction long-axis model shrinked,east-west direction short-axis model developed symmetrically and mainly in eastern model.On the fundamental of synsedimentary fault recognition and the researching on its evolution characteristics,the palaeogeomorphologic pattern between Shahezi formation and Denglouku formation was reconstructed,and five palaeomorphologic units were recognized.According to the combinatorial arrangement relationship between palaeomorphologic units and different zones of fragments into the basin,this paper summarized six source supply styles,and discussed the influences of differenct styles on sediment.According to core,logging and seismic data,this paper defined the sedimentary facies recognition template,and recognized six sedimentary facies,ten sedimentary subfacies and fourteen micro-facies,among which were fan dalta-lake sedimentary system between Shahezi formation and early Yingcheng formation,braided river delta-lake sedimentary system between late Yingcheng formation and early Denglouku formation and braided river delta sedimentary system in late Denglouku formation.On the basis of mentioned research,the source-to-sink system formation models in different sedimentary period between Shahezi formation and Denglouku formation were established,with Shahezi formation,Yingcheng formation and Denglouku formation respectively developed six,four and three models.In the end,this paper discussed the influence of source-to-sink system on favorable reservoir sandbodies,and predicted its distribution zone in different stratums according to the arrangement relationship among sedimentary facies,current tectonic landform,and source rock.