Study On Glutenite Bodies Depositional Stage Division

In Paleogene Shahejie Formation,large scale fans developed in the northern steep slope of Dongyingsag,which was caused by the fault depression of the basin,tectonic movement and change of ancient climate.The fans can be divided into alluvial fan,fan delta,near-shore subaqueous fan and various combinations of fan body.Northern steep slope can be divided into eastern,middle and western part.The types of fans were different due to the various activity levels of Chennan fault,Lijin-Binnan fault zone and Shengbei fault zone in the fourth member of Shahejie Formation.For the glutenite bodies in Lijin north zone in western part of northern steep slope of Dongying Sag,using theories and methods of petroleum geology,sedimentology,lithofacies and paleogeography,stratigraphy and logging geology,and combining the core data,logging data and well-logging data,we researched its glutenite bodies which depositional stages and facies are not clearly demarcated.According to the paleoclimate change,the ancient tectonic activity and provenance of conglomerate bodies,we can find that the paleoclimate turning cold to warm and the precipitation increasing gradually in sha-4 zone of Shahejie formation;source area comes from the north Chenjiazhuang uplift which is relatively single;the deposition of sha-4 is mainly controlled by Chennan fault,while the Lijin-Binnan fault and Shengbei fault are not active;the activity of Chennan fault is relatively strong in Chunxia stage of sha-4,while its west part(Li Jin)decreasing in Chunshang stage,and middle part(Sheng Tuo),east part(Yan Jia)'s activity is rather strong,which resulted in the different development of fans in north steep slope.Through the 6 well coring's observation and description out of 7 well coring,demarcation of the sedimentary facies,sub-facies,microfacies,judgment of the paleography features,the distribution of fans can be determined that root,middle and rim fan developed from north to south,multi-stage fans were overlay.The types of sedimentary facies in study area: fan delta deposits are usually shown in early sha-4,while it transit gradually to near-shore underwater fans in late sha-4 stage.The stage subdivision of single well is mainly relied on rock-electric phase mode which built by core facies and logging curves,then dividing the stages of connected well via the result of single well demarcation,from that we can know,the deposition of sha-4 of Shahejie formation is comprised of 4 fan deltas and 3 near-shore underwater fans which appears a overlay relationship overall.