Hydrocarbon Exploration Perspective Analyse Of Lower Cretaceous In The Songjiang Basin, Jilin Province

Songjiang basin is a composite Meso-Cenozoic sedimentary basin whichis located in Antu County who belong to the east of Jilin province.Theacreage of Songjiang basin is about750Square Kilometers.The extent ofgeological research is lower. The direction of basin tectonic whose mainpart is comsist of Songjiang syncline is north east, and it is dispersedSongjiang town to Xiaoshahe village.There mainly developed fourFormations,including Maoershan,Xishanping,Changcai and DalaziFormations of Lower Crataceous in Songjiang basin. Maoershan Formationis mainly neutral volcanic rock with pyroclastic rock mixed.Xishanping,Changcai and Dalazi Formations are clastic rock with coal oroil shale.The author carry out basal oil and gas geology survey to Songjiangbasin by gravity and magnetic interpretation and field geologicengineering including observing outcrop,shallow west,test trench and soon.The result reveal that there are thicker melanocratic mud rock and widedistributional oil shale in the Dalazi Formation, thin melanocratic mudrock and coal in the Changcai and Xishanping Formation;Besides,lots ofsand bodies develop in each strata of Cretaceous in this area,reservoirstrata whose thickness is about1300meters is mainly Changcai Formationand the first Member of Dalazi Formation,The article detailedly evaluate organic material’s abundance，types， mature level of source rock and poroperm characteristics of reservoirstrata by systematic sampling to Dalazi and Changcai Formation of LowerCrataceous and test on several geochemiacal indicators in Songjiang basin.Combining characteristics of source reservoir seal assemblage, analyseand dicuss hydrocarbon exploration perspective of Songjiang basin.Itcomes to a conclusion that the second Member of Dalazi Formation, occurredin the extremely thick Lower Cretaceous cover strata,is the most abundantsource rock interval in which organic material is at very high content,relative better types, as well as mature level, and owes the betterhydrocarbon-genetic potential; In addition, the reservoir strata is alsowidely developed in the Changcai Formation and the first Member of DalaziFormation,which provides certain reservoir conditions for hydrocarbonaccumulation;Meanwhile,the huge thickness’s mud rock in the secondMember of Dalazi Formation is favourable capping formation while it isfavourable source rock.Because of time and space configuration ofabove-mentioned units of source reservoir seal,it has been developedfavourable condition of source reservoir seal assemblage in Songjiangbasin,it is mainly that the downward migration dominated combinedcondition of hydrocarbon play.Therefore, the source rock bearing basinis somewhat small in size, however, in the extremely thick lowerCretaceous cover strata which contains coal and oil shale,creatingfavourable basic condition of hydrocarbon accumulation,present goodhydrocarbon exploration perspective, and finally become one of the morepreferable target area for hydrocarbon outside of the Songliao basin.