Prediction Of The Northern Songliao Basin And The Western Slope Gaotaizi Reservoirs High-resolution Sequence Stratigraphy And Lithologic Traps

Western-slop is a secondary structure unit of northern Songliao basin, and there are more than 260 wells in this area. For a long time, much detailed research has been carried in every single zone, but we havn't studied the whole area as a unity for some reasons. For deeply explore, using all the ways such as seismic data, log-testing data, lithology, paleontology, and heavy minerals testing data, in addition to lots of log-cores observation, we studied GaoTaizi oil-layer (qn2.3 section) high-resolution sequence in western-slop as a whole area .on base of the sequence result, we studied sediment faces and drawn the ichnographies. at last forecasted stratum-litho trap. For sequence dividing, we first identified a second-rank sequence interface and two third-rank sequence interface in the seismic data and well logging data. these surfaces overlap with fourth-rank sequence interface in target stratum. Distinguishing the seismic data being limited, we identify the four-rank interfaces depending on rocket radioactivity and the characters of well-logging. Combining the belts of Cypridea fossils and achievements of studying the sandstone groups, we identify the four-rank sequence and its system tract through analysis lithology-electricity of logs. In the end, five four-rank sequences were identified in the target stratum in which we summarized ten characters of lithology-electricity. Trough two wells joint section of sequence ,we know that every four-rank sequence become thin and fade away from east to west. But there are not this character from north to south. On the other side, we studied the sediment system of this region relying on previous fruition of sequence stratigraphic and using record of well-core, well-logging and seismic data and other analysis results. Firstly, by observing 24 wells core and other information, characters of facies, subfacies and microfacies be sat up. Then , using the system tract of four-rank as the unit, we have drawn 10 sediment ichnographies of this region, whose evolving laws and patterns of sediment have been summarized. Finally, on the base of studying sequence stratigraphic and sediment facies of this region, we doped out the distribution of strati-litho trap, drawn trap ichnographies using fourth-rank sequence as the unit.