Study On Sequence And Sedimentary Of K₁qn Stratum In The West Wlope Of Songliao Basin And Forecast Layer-lithology Traps

Depend on lots of seism, log, well, core, geochemical and paleontology and so on, Icarefully and systemically researched the sequence and sediment system of K1qn (Gaotaizi oillayer) of middle combination in west slope of Songliao basin. Find out the characters ofsequence interior structure and key surface in two, three, four grade sequence. Four gradesequence is middle time cycle of high sequence. Established sequence partition plan and studieddeeply its interior structure mechanism and characters of space distribution. The thickness oflayers in different sequences became thinness from east to west. For four grade sequence, thispaper pointed C5 was the smallest in space distribution and only indwelled in southeast of westslope. Find out the characters and types of sedimentary facies, sedimentary subfacies andsedimentary microlfacies in this area and established facies symbols. In this area these papersfind two types of sedimentary facies, lake and delta. Lake contains shore-shallow lake and lakebay. Shore-shallow lake divided sand beach, mixing beach and mud beach. Lake bay containedmud sediment and carbonate sediment. The delta contained delta plain, delta front and prodelta.Delta plain divided distributary river course and between river courses. Delta front containsmouse bar and distal bar. Find out the characters of different types of facies distribution. Threegrade sequence SQqn2 and its four grade sequence mainly developed lake and delta facies.From down layer to upper, the delta extended stepwise. The transgresslve systems tract of threegrade sequence SQqn3 contains C3 and its delta facies is limited, lake covered large areas,sediment mainly contains carbonate sediments. The highstand systems tract of three gradesequence SQqn3 contains C4, C5 and sediment region shrink from west to east, delta extend toeast and lake area became smaller. Above many researches help me summarize sedimentevolvement orderliness, controlling factors and sediment facies modeling. Ancient topographty,lake surface change, lake shore line and north source, qiqihaer source, west source, southwestsource controlled the sediment process of K1qn in west slope of Songliao basin. The sedimentstructure of this area contains delta, shore-shallow bar, shore-shallow mud and carbonate mixingbeach. In forepart and middle of K1qn23 the lake shore line popple on main body of west slope.During the power source supply period, delta developed quickly and after source died down,lake bay became developing. In the late of K1qn23 the lake shore line popple on the east of westslope and source died down, small delta developed. On base of sequence and sedimentary faciesresearches, this paper analyzed the cause types of layer-lithology traps and forecasted trapsdevelopment area. The trap contains sand lentoid traps formed by sand bar and sand updipwedge-out traps. The sand lentoid traps developed in the middle and east of area, sand updipwedge-out traps developed in the east of research area.