The Sedimentary Characteristics Research On Deep-water Gravity Flow In West Talaha-yingtai Region

Gravity flow exploration has occupied the important position in the field of exploration since 1970’s. However, the research on gravity flow deposits in our country at present is not very mature, many theoretical and practical exploration problems are still work in progress, which is gradually discovered and perfected. Based on the comprehensive analysis of cores, well logging, testing and seismic data, and combining the latest progress in the study of deep-water gravity flow at home and abroad, our paper set Qingshankou formation of west Talaha-Yingtai area in Songliao basin as the main research object, and have systematically research on the sedimentary characteristics of large depression lake basin gravity flow, identification, distribution, and exploration potential.In this paper, third and fourth sequence in Qingshankou formation of west Tallaha-Yingtai area are identified and classified, which mainly identified at the bottom of the erosion surface, dam top, mudstone base value point, the maximum flooding surfaces in four sequence boundaries. Additionally, the four levels of sequence stratigraphic framework is established based on the divided three mid cycles and 12 medium-term cycles in the study area of Qingshankou formation. According to the ancient form recovery of the Qingshankou formation in the study area we can see that the average slope of K2qn1 to K2qn3 is 0.2°~0.5°, and gravity flow is mainly formed and controlled by the slope break belt. Multistage landform is not only controlled the formation of gravity flow but also controlled the gravity flow form, dual fan is easy to be formed due to the multistage slope break belt, and the formation of superimposed fan is controlled by the large low-lying physiognomy. Pit gravity fluid is formed by the breaking pit landscape, and the gravity flow in the form of multistage geomorphic is corresponding to different reflection on the seismic reflection characteristics. In this article, it is elaborately described the characteristics, identification, distribution and morphological description of four kinds major developed gravity flow in the study area. By analyzing the grain size and C-M figure which are made for one of the most principal of sandy debris flow, it shows the duality between the traction current and gravity flow characteristics. The analysis of slices of seismic attributes reveals that the change of ratio between sandstone and stratum thickness has an important effect on seismic reflection characteristics. The reservoir properties of gravity flow sandbody have a very good advantage due to the effects on their mode of transport, sediment overpressure environment and dissolution of organic acids. It suggests that exploration potential is considerable by analyzing the research area where has 217 entrapments, and every single area of entrapment is about 0.3-15 Km2 and the total area is 161.5Km2. The ideas and research results in the paper make a contribution to the theory of continental lake basin deep-water gravity flow deposits, and has real significance in the deployment of future exploration in Daqing Oilfield.