Sedimentary Characteristics And Trap Descriptions Of The Donghe Sandstone Section To The Bachu Glutenite Section In The Halahatang Sag

Dongheshayan Member and Bachu Formation Shaliyan Member of Halahatang Depression in early stage exploration have found that a lot of industrial oil wells,which shows vast potential.However,there are some questions,such as,stratigraphic division is not unified,the sedimentary facies recognition is obscure.Guided by the theories of Sequence stratigraphy,Sedimentology and Seismic stratigraphy,combining with well-logging,mud logging,core analysis,outcrops,three dimensional seismic data.Demonstrated the the ownership of Dongheshayan and divided the-third-squence and the-fouth-squence of Carboniferous system and Devonian system.On the basis of Sedimentary facies identification,the sedimentary system was established.Analyzing the distribution of the sedimentary facies in different period,the Sedimentary facies model was established.Combining with geology and geophysical,for the key trap carry out meticulous depiction.Predicting the oil-bearing area.Accoring to High-resolution Sequence Stratigraphy.Carboniferous system divided into the-third-squece which have four(SQC1-SQC4).SQC4 was absent in research area.Bachu Formation developed the-third-squence SQC1 that have only one.Among which Shaliyan Member corresponded to SSQC1,Xianiyan Member and Shengxiehuiyan Member corresponded to SSQC2.Devonian system developed the-third-squence which have one and the-fouth-squence which have six(SSQD1-SSQD6).Dongheshayan Member-Shaliyan Member devoloped wave-control-shoreland facies?wave-dominate-delta facies?fan delta facies?mixed coast facies and so on.Including 10 subfacies and 14 microfacies.Vertical evolutionary series of sedimentary facies:wave-control-shoreland facies to mixed coast facies,wave-dominate-delta facies to fan delta facies to mixed coast facies.Sedimentary thickness become thinner horizontally form northwest to southeast in Dongheshayan Member.Vertically,it is developed sediment deposited alternately of shoreface and foreshore.Shaliyan Member's sedimentary thickness is stability.The continuity between sandbodies is not good.The plane distribution of sedimentary facies in Dongheshayan Member shows that in the period of SSQD1-SSQD2,the wave-dominate-deita from northwest developed scope is limited,but the wave-control-shoreland from southeast developed extensively.Between them,under shoreface develpoed at most.In the period of SSQD5-SSQD6,the wave-control-shoreland from southeast and wave-dominate-delta from northwest become wide,but the sedimentary belt between them become narrow.The plane distribution of sedimentary facies in Shaliyan Member shows that form northeast to southwest,sedimentary facies successively developed fan delta plain?fan delta front?pro-fan delta?mixed coast.The resevoir type in Carboniferous system Shaliyan Member is lithological reservoir.The geostatistics inversion can depict distribution of sand bodies effectively,predicting the distribution area of Ha6 sand body is 8.8km~2,area of Repu 6 sand body is 6.8km~2,sand body thickness is 0-8m;area of Repu 702 well drilling sand body is 1.7km~2,sand body thickness is 0-5m.The resevoir type in Dongheshayan Member is structural reservoir.Predicting the oil bearing area of Donghe4 is 3.48km~2,the oil bearing area of Donghel is 6.9km~2.