Research Of High Resolution Sequence Stratigraphy And Sedimentary Facies In Dabusu Area Of Jinlin Oilfield

Dabusu area in south Songliao Basin stretches across the west slope and the central depression two big tectonic elements and lies in the steep slope and the front delta zone. It has the conditions of lithology reservoir-forming. Through researching sequence stratigraphy, depositional system, sedimentary facies of west slope at south Songliao basin, This paper builds up superposition fashion of sedimentary sequence and evolution rules of sedimentary facies, analyzes reservoir genetic type and distribution rule of Dabusu area. The article supplies the geological foundation for the eyemark optimize at the earlier periods of the exploitation.The research area's unconformity surface is not easy to be distinguished, so we distinguish and divide sequence stratigraphy applying of high resolution sequence stratigraphy through distinguishing the interface. We divide five long term base level cycles and nine middle term base level cycles on Quantou-4 member-Yaojia formation, build up the sequence stratigraphy framework through combination of well and seismic.Based on the research of regional sequence stratigraphy and depositional facies, this paper put forwards the studied section sedimentary model in sequence stratigraphy framework. The base level rising period develops braided river-turbidite fan-deep lake depositional systems, the base level descending period develops low sinuous river deposits- delta regime-luxoturbidite-semi-deep lake depositional systems of the Qingshankou formation third-order sequence. The Quantou-4 member third-order sequence develops meandering river-deltaic deposit and shore saucer lake deposits.Based on the regional sequence stratigraphy and depositional systems, fifth -order sequence framework of Qnl-2 member has been established in Dabusu area. In the fifth - order sequence stratigraphy framework,Taking the core sample material as the basis and union well logging and the sizing test material,identification sign of microfacies has been established and the type of microfacies has been cleared.This paper studides the reservoir distribution rules and evolution characteristics in the fifth - order sequence stratigraphy framework.In the end, based on high accuracy sequence and deposition research, using the knowledge of geology and hydrocarbon accumulation, forecasts trap of Qnl-2 in Dabusu area.The result is that base-level rise of the turbidite sand is conducive to the formation of lithologic traps reservoir, overlap bodies in water invasion period devolep widely, it is a important deposit body to form. stratigraphy overlap traps.