Fine Sedimentary Study And Application Of The Upper Member Of Guantao Formation In Feiyantan Oilfield

Adopoting the theories of high-resolution sequence stratigraphy and sedimentology, combined with data of core, seism, well logging and logging, base-level cycles are identified, sequence stratigraphy framework has been constructed and stratigraphic classification and correlation have been done. The upper member of Guantao formation in Feiyantan oilfield can be divided into three middle sequence cycles, they are MSC3, MSC2 and MSC1 from the bottom to the top, MSC3 are consists of three short term cycles. MSC2 are made up of two short term cycles. MSC1 are divided into four short term cycles. Every short term cycle is consists of half-cycle.The indexes of sedimentary facies, the types of sedimentary microfacies, the longitudinal evolution and the special spreads of sand bodies are systematically studied in the sequence stratigraphy framework. The facies of the upper member of Guantao formation in Feiyantan oilfield in Chengbei sag are river, delta and lake. River facies are developed with channel, point par, channel par, natural levee and crevasse splay. Delta facies can be further divided into the delta plain subfacies, the delta front subfacies and the prodelta subfacies. Shore-lake and meare are recognized. The third, second and lower part of first of MSC3 are braided rivers facies. The MSC2 are lake-delta environment. The environment of MSC1 are changed with the times, entirety from lake-delta to meandering river.On the basis of the sequence stratigraphy framework and sedimentary characteristics, combined with fundamental qualification of oil geology, the roles of oil accumulation controlled by stratigraphic sedimentologi are probed. The member and range of profitability sandbodies are predicated.