Evaluation Of Source Rocks Of Middle And Lower Jurassic Of Western Area Around The Songliao Basin

In recent years,due to new developments in the development of oil and gas resources,the basin group in the western region of the outer periphery of the Songliao Basin has been paid more and more attention by researchers.Among the basin groups in the western region of the outer periphery of the Songliao Basin,the Zhalut Basin and Tuquan Basin are oil and gas prospect basins discovered in recent years.The study area is mainly filled with a set of Mesozoic strata,and good source rocks have been found,with certain exploration prospects.The Jurassic is widely distributed,mainly exposed by volcanic rocks,and the sedimentary rocks are relatively poor.A large number of Jurassic volcanic rocks are covering the old strata in the northern Erguna-Genhe area,the central Horqin Youyiqianqi-westo of Tuquan-Holinguole area,and the southern Bahrain ZuoqiBalingyouqi.Through detailed field geological surveys and the collection of drilling seismic data,the sedimentary facies of the Tuquan Basin and Zhalut Basin have been clarified.Two types of sedimentary facies were identified in the Wanbao Formation in Tuquan Basin: fan delta facies and lacustrine facies.Four sedimentary subfacies,seven sedimentary microfacies,and volcanic facies were divided.Shallow lake subphase transition.Three types of sedimentary facies were identified in the Early-Middle Jurassic of the Zalut Basin:alluvial fan facies,fan delta facies and lacustrine facies,and 7 sedimentary subfacies and12 sedimentary microfacies were divided;the Hongqi Formation sedimentary system behaved longitudinally It is the change sequence of fan delta plain-fan delta front-lake marsh-sand(mud)shallow lake-semi-deep lake-sand(mud)shallow lake-shore shallowlake;the sedimentary system of Xinmin Formation is fan delta in the longitudinal direction Variation sequence of plain-fan delta front-lake marsh-sand(mud)shallow lake-semi-deep lake-sand(mud)shallow lake-lake marsh.Dark mudstones are developed in the study area,and the test results statistics from the Tuquan Basin show that the dark mudstones of the Hongqi Formation are good source rocks with type Ⅲ organic matter,which are in the high-maturity-overmaturity stage and are good source rock horizons in the basin;Wanbao The dark mudstones in the group are good source rocks,and the type of organic matter is type III,which is in the stage of high maturity-overmaturity,which is conducive to oil and gas generation.The source rocks of Hongqi Formation in Zhalute Basin have poor organic matter abundance,type III organic matter,which is in the stage of high maturity-over-maturity,which is unfavorable for oil and gas generation;It is in the stage of high maturity-overmaturity,which is not conducive to oil and gas production.Tuquan Basin mainly formed two types of combination of self-generated self-reservoir and lower-generated super-reservoir,which are favorable exploration target areas in East Durki and Pingyuan Village.The middle and lower Jurassic lacustrine dark mudstone provides a sufficient hydrocarbon generation material base;the clastic rock deposition of the fan delta formation provides oil and gas reservoir conditions;the dense mudstone of the Wanbao Formation and the thicker volcanic rocks developed in the upper part can form favorable Cap layer.