Research On Sequence Stratigraphy Of Nantun Member In Northern Area Of Beixi Slope

Based on the recent theory and method of Sequence Stratigraphy, Sedimentology and Seismic Stratigraphy, this paper uses seismic, logging and core information to analyze and research the sequence formation framework and sedimentary facie of Nantun member in Beixi slope belt deeply. Moreover, combined with structural geology feature of Beier depression, the combination law of oil source bed, reservoir, and cap rock of Nantun member is studied and the distribution area of favorable sand body is predicted. The result offers the dependable evidence for sequence division, and it is significant for the exploration and development of oil and gas.According to seismic, comprehensive logging, logging and core information, this paper classifies Nantun member of Beixi slope into two three-order sequences according to the principle of correlation between wells. From bottom to top, K1n1 is a full set of three-order sequence, so is K1n2. T23 reflective layer is the sedimentary transformation surface between the two three-order sequences. This paper tracks out two seismic reflective layers in the system tract and describes the features of each sequence and system tract.On the basis of sequence division, sedimentary environment and sedimentary facie, it is determined that research area has muti-sources. Nantun member sedimentary system is mainly fan delta-lake-sublacustrine fan sedimentary system. Source direction is mainly from west side, northwest side and southwest side. Meanwhile, sedimentary ideograph of each system tract in research area is completed combing with evolution n characteristics of the basin and lithology changes.This paper predicts two favorable perspective plays by comprehensively considering basic conditions for the formation of reservoir (source bed, reservoir, cap rock and trap, etc) and distribution of sand bodies.