Sedimentary Facies Of AⅡ Oil Group In A - 3 Section Of Hananfu Special Area

Hananfute area is located at the A’ershan tectonic zones of the A’nan depression in the east of Magni org in Erlian basin. The working area of this paper includes H22and H43fault blocks. HananfuTe Reservoir belongs to low porosity and medium-low permeability lithologic reservoir.The research of the paper is main about the sedimentary facies of All formation(A3member) in the Hananfute area. Based on the regional geology of Hananfute, with the guidance of sedimentary petrology, logging geology, reservoir stratigraphy and other basic theories and methods, plentiful information of well logging and cores is used to do a precise stratigraphic division and comparison of All formation of66wells.AII formation can be divided into upper portion and lower portion, of which the lower All formation is the focus of this paper, and it is subdivided into seven small layers:All-1, AII-2, AII-3, AII-4, AII-5, AII-6, AII-7.Based on the sedimentary signs (such as rock type, color, composition, sedimentary structures), logging signs and seismic signs, the paper has carried out the analysis of sedimentary facies of single well and well profiles.As a result, it is perceived that the upper All formation developed lacustrine facies and the lower All formation developed Fan-delta front subfacies. Lacustrine facies shallow lake mud and beach bar microfacies; Fan delta front facies includes subaqueous distributary channel, subaqueous distributary channel edge, mouth bar and front sheet sand which can only be recognized on a single well. On the basis of it, the sedimentary microfacies of each small layer in the lower All formation have been drew out, with the distribution rules of flat sedimentary facies defined and the depositional model established.Through the reservoir physical property analysis of lower All formation in Hananfute area, the reservoir physical property of AII-7layer ranks the first, and AII-6layer ranks the second, while AII-2layer ranks the last; The reservoir lower limit has been defined: porosity is greater than or equal to4.3%; penetration is greater than or equal to0.2×10-3μm2. Based on the sedimentary microfacies research and physical property analysis of small layers, the subaqueous distributary channel sandstone is the main favorable reservoir belt, and the subaqueous distributary channel edge sandstone and mouth bar sandstone is the second favorable reservoir belt.