Sedimentary Facies And Hydrocarbon Accumulation Of Chang8 In Huanxian Area Of Ordos Basin

The southwestern margin of the Ordos Basin Group of Upper Triassic geological profile fieldof literature, described in the study area based on core observations, combined with logging,drilling, logging, etc., through the thin section, light minerals and heavy mineral analysislaboratory analysis testing means of application of sedimentology, facies of ancient geography,geophysical logging, petroleum geology and other disciplines, new theories and new methodsto extend the southwestern margin of the Ordos Basin Formation and the Central County ofGansu 8 strata was long source analysis of depositional systems and sedimentary facies studyreveals 8 Yanchang temporal distribution of depositional system rules of the reservoir, reservoirand seal assemblage relations.Specific work for the data collection, digestion and analysis of regional sedimentaryevolution of the background based on the core observation, the study area to determine therock phase, the use of logging data to establish log phase, determine the study area,depositional systems and facies, and the single well core Sedimentary microfacies.Source analysis study shows that in the study area west of the ancient flow direction, thesouthwest, followed by the northwest, northeast of the second. Around the southwest edge ofthe Ningxia ancient uplift, the Liupanshan ancient land and the Qinling Longxi ancient land isXifeng Oilfield 8 Upper Triassic strata head of the main source area of the study area in theNortheast source may come from the northeastern margin of the basin Luliang, Yin crystallinebasement area, is the secondary source area.According to the literature described outcrop, drilling data and well logs compiled acomprehensive study and an indoor map, based on comprehensive geological background,lithological, and paleontological characteristics of the sedimentary structures of the study areaextend the head of the Triassic oil group was 8 into braided delta, fan delta and lake facies. Andfurther identified seven kinds of sub‐phases, namely: braided delta plain, braided river deltafront, the former braided river delta, fan delta plain, fan delta front, fan delta, shallow lake.Yanchang is the most important oil‐bearing basin strata, reservoir type and by studyingthe relationship between sand, and Chang 8 of the sedimentary system, sub‐phase micro‐phasecombination of features, and favorable vertical evolution reservoir sand bodies of the distribution of further research to reveal temporal and spatial distribution of depositionalsystems, thereby strengthening the group looking to extend the high‐yield, high abundance ofoil and gas accumulation zones integrated study has important theoretical and practicalsignificance.