Sedimentary Facies in the Second Member of Dainan Formation, the South Slope, Gaoyou Sag
|School||Ocean University of China|
|Course||Mineral prospecting and exploration|
|Keywords||Gaoyou Sag Dainan Microfacies Braided delta Depositional model|
Southern slope of Gaoyou Sag complex reservoir distribution, reservoir distribution range of small, fine exploration has long restricted the development requirements of sedimentary facies and hydrocarbon accumulation in relation to propose effective exploration and development strategy. In this thesis, contemporary art sedimentology, sequence stratigraphy, reservoir geology, new ideas, new theories and new methods as a guide for the southern slope of Gaoyou Sag wearing Sec reservoir facies study, which is the southern slope Huang Jue, Zhenwu - caozhuang, enriching, Zhouzhuang and other areas of exploration and development role. This study uses multi-level sub-stratigraphic cycles of theory and research methods, combined with the evolution of sedimentary facies sequence will wear Sec divided into a long-term base level cycle, five mid-level cycles, established sequence stratigraphic framework ; through sedimentary petrology and facies marker analysis, a clear provenance and paleo-flow direction, studies suggest that the southern slope of Gaoyou sag source direction Sec worn mainly from the southern edge of depression Tong Yang uplift, Gaoyou Sag east - southeast wubu convex from the hinterland narrow elevation is small, is secondary Gaoyou sag source direction, mainly supplied to Zhouzhuang region debris; Fumin Village area north and south two parties to accept source supply, its provenance mainly from the northern region in northern Gaoyou sag Zhe stack direction. Sec major southern slope of Gaoyou Sag wearing braided delta system, according to the detailed description and analysis of the core study area is mainly braided delta front, the main distributary channel sand body types and front sand dam. Distributary channel bifurcation, diversion frequent sand thickness in the vertical superimposed over the river several times the depth of cut laterally connected to each other to form a multilateral sand, so distributary channel deposits constitute the southern slope of the skeleton wearing Sec sand body; while the leading edge of the dam due to frequent migration interconnected river, was shaped skirts distributed along the delta front, resulting in Zhenwu - caozhuang, Zhouzhuang region, particularly in the wealthy - Xu Jia Zhuang region formed a large-scale sand composite body. In each sub-section of the spatial distribution of sedimentary facies, based on the establishment of the southern slope of Gaoyou Sag Sec wearing braided delta sedimentary evolution mode. Dai Sec is a water receded during the deposition process, during the advance and retreat of the lake with the secondary, source supply changes in strength to a certain extent control the development of braided delta scale, so in addition to a braided delta depositional upward change Rough, thickened, the plane gradually advancing trend, it will also appear secondary fluctuations. Enriching gentle slope belt in the northern part of the leading edge, wearing Sec deposition period, Lakes narrowed and shoreline continued southward, from the northern Zhe Gaoyou Sag stack direction constantly push southward braided delta, where the formation of North and South substances alternating deposition. Depositional systems in both directions north and south, in the absence of the deposition process vast space between two braided delta system with ill-defined. Huang Jue region near the source area, but the braided channel carrying capacity, well developed braided delta mudstone, sandstone with isolated type of distributary channel sediments, front sand dam is very developed, in view of Huang Jue braided delta region braided delta and the general distinction that this study raises Huang Jue region rich mud braided delta depositional model.