The Research Of Sedimentary System Of The Funing Formation In Gaoyou Depression

The Gaoyou depression is the major oil exploration zone in Jiangsu oil field. According to the exploration level of upper and middle formations are high in Gaoyou depression, the next exploration direction are deeper formations. The Funing reservoir is important formation in deeper formations. As a result, the sedimentary system research and advantage sandbody distribution regular research can provide the next exploration direction. The followings are the research methods and results:First, grounding on stratigraphy of lithologic sequence and theory of sedimentology, choosing traditionally formation divided method, the typical claystone section is marker formation in the area, sand body from the upper part of E1f1 section of Gaoyou depression are divided into two sub-section, which are respective E1f12 and E1f11 from bottom to top. And the formation of E1f3 section in Gaoyou depression are divided into three sub-section, which are respective E1f33, E1f32 and E1f31 from bottom to top. And the sub-section E1f31 are divided into two sand bed groups, which are respective E1f31-2 and E1f31-1 from bottom to top. The formation framework of the research area is established. Therefore, the paper consider that the formation thickness of the research area during E1f1 is little different, the formation thickness of the two sub-sections during E1f1 is about 100 meters; and it is a big different during E1f3, the formation thickness of the est area is thicker than the west area, and the E1f32 sub-section is the thickest sub-section during E1f3.The study of sedimentary environment of Fu-Ning formation of Gaoyou depression is carried out through rock core observation, log response feature, test analysis and the predecessors'research based on formation framework built. And the study make clear that they are most developed delta facies during sediment of E1f1 and E1f3 section in Gaoyou depression.and the delta facies here can be further divided into three subfacies which are composed of delta plain,delta front and prodelta,and these subfacies include ten microfacies which are composed of distritary channel, natural levee, crevasse splay, distritary bay, sub-distritary channel, sub-distritary bay, mouth bar, distal bar, sand sheet and prodelta clay.Through analyzing the evolvement of sedimentary in every layer, it is found that sand body in south of the depression present retrogradation while sand body show progradation deposition in north of the depression from sub-section E1f12 to E1f11 during E1f1. Sediment pattern is almost no different in every layer during E1f3, which is basal the framework that express differentiation in east and west and show progradation-retrogradation cycle in vertical direction.Finally, based on analysis of the study of single phase, section phase and plane phase, we established the sedimentary facies model of E1f1 and E1f3 section of Gaoyou depression in the plane and vertical direction.