Study On Slumping Turbidites Of Delta Front In Honggan-Yingtai Region, Songliao Basin

The fluxoturbidite in front of delta is an important field of lithologic hydrocarbon reservoirs in mature basins. Systematic research are carried out through the sequence division, sedimentary facies analysis and sand body distribution of the fuxoturbidite in front of delta of member I and II of Qingshankou Formation in HongGang-YingTai region in SongLiao basin by means of drilling, logging, seismic data and some previous data.Through cores observation, seven types of lithofacies can be recognized in the fluxoturbidite in front of delta. It generally develops among several sets of large mudstone. The changing and aliasing of electric logging curves are obvious when the thickness is big. It takes on box shape as a whole and has typical dentate shape. From the logging data, the lithology granularity is fine, and this section is dominated by aleurolite, argillaceous siltstones or silty mudstones. From the seismic data, seismic profile is characterized by lens-shaped reflection. Through analyzing the probability granularity curve diagram, we can identify its curve pattern is typical two stages.This paper takes the high-resolution sequence stratigraphy theory as guiding theory, we can recognize key interface of different scales of base level cycle. We can confirm that Member Qin I and II is a long-term cycle, it can be subdivided into three fourth cycles. In short, if a slope-break zone exists, a bypass surface will form turbidite sedimentation under the zone. Otherwise, it is just the redeposition of fluxoturbidite in front of delta. After sequence division, we can conclude the characteristics of stratigraphic framework as follows: Acension and descending half cycle of lower sequence of Member Qin I and II are symmetric, the thickness of ascension half cycle of middle sequence is significantly thicker than descending one, however, in upper sequence, the situation is in the opposite.The research area mainly develops delta front intrafacies and forms slump turbidite lithofacies. The delta plain deposits only develop on the upper of slope in the northern part of the researched area. Delta front physical property is dominated by fine sandstones and siltstone. It develops underwater distributary channel, rivermouthbar, sand sheet, submerged distributary tributary bay microfacies. The fluxoturbidite consists of turbidity water way, lingula, distant lingula and turbidite sand sheet. In addition, the researched area has developed deep lake and half deep lacustrine facies deposits. Therefore, synthesizes the above analysis, we optimize the thicker turbidite fanlike sand body, and in the relatively high position of this area, we look for the sand body for hydrocarbon accumulation. And at the same time, analyzing and predicting favorable zones in the corresponding reservoir, which provides scientific basis for Jilin oil field on further exploration and development.