Analysis Of High-resolution Sequence Stratigraphy And Sedimentary Microfacies In 4^th Member Of Quantou Formation Of Haituozi Area In Jilin Oilfield

Haituozi area in south Songliao basin lies in the south of the Daan-Honggang terrace of the Central Depression area, west of the Western Slope and east of Qianan Depression. The extent of the exploration in the target area is relatively low and there are large areas of small structural and hidden lithologic reservoirs. This paper sets up superposition fashion of sedimentary sequence and evolution rules of sedimentary facies, analyzes reservoir genetic type and distribution rule of Haituozi area in order to provide reliable geological basis for further exploration and development in future.Applying the theories of high-resolution sequence stratigraphy, the paper classifies the layer of Quantou Formation in Haituozi area through the combination of core, well and seismic. One long term base level cycle, four middle term base level cycles and twelve short term base level cycles are identified in the target area. Analyzing structural type of short term datum level cycle, the paper identifies two main types which are up-deeping asymmetry(A) and symmetry from up-deeping to up-shallowing(C). Further in the light of the high or low accommodation, two subtypes of structure are distinguished. At the same time, high-resolution sequence stratigraphic framework are built up in Quantou Formation of Haituozi area.According to the mudstone color value charts, the characteristics of heavy mineral assemblages and analysis of cast thin sections, oxidation and weak reduction are identified and source come from the north-east and south-west of the target area which climate is dry and hot. The reservoir sandstone are primarily litharenite and feldspathic litharenite.The sedimentary facies identification is built up and Terminal fan system is firstly confirmed on the Quantou Formation of Haituozi area with the study of core, well and grain size datum. The target area lies in the distributary zone which microfacies are distributary channel, proximal overbank, distal bank and mudflat. The sedimentary structures in Terminal fan are different from other types. Parallel bedding which is the most special trademark often occurs on the channel erosion surface and mud-stripe are abundant in sandstone. On the basis of analysis of the sandstone of layers and microfacies, sand body plane graphs, sedimentary microfacies plane and profile graphs about each layer and sedimentary model are drawn in order to study the reservoir distribution rules and evolution characters.