Architecture And Remaining Oil Distribution Analysis Of Fan Delta In Kongnan Area Of Huanghua Depression

Sand of fan-delta,a kind of important oil and gas reservoir,widely distributes in the rift lake basin in China.However,for the producing of fan-delta sand,there are several problems,such as fast changing laterally,complex superimposed pattern,high dispersion of remaining oil and high difficult in late development.Therefore,it is necessary to dissect reservoir,analyze internal structure and find the distribution law of remaining oil.z? and z? oil group in K1 formation of Kong South area of Dagang oilfield is studied in this paper.The data includes the core,logging data and production dynamic data.First of all,correlating isochronous strata was established,and the sedimentary system and sedimentary facies types were then analyzed.Secondly,the types,superposed relationship and quantitative scale of architecture elements of fan delta front was analyzed,and then the three-dimensional geological model of single genetic sand body was established.Finally the distribution law of residual oil under reservoir architecture control was analyzed.Research has shown that the strata in Kongdian 1th formation of Kong South are of Dagang oilfield is proportional deposition pattern;The type of sedimentary facies in the study area is fan delta;The assemble patterns of microfacies sand of fan delta front include the combination of dendritic distributary channel with contiguous mouth bar,the combination of contiguous distributary channel with contiguous mouth bar,the combination of dentritic distributary channel with single mouth bar,and dentritic distributary channel with sheet sand;Single distributary channel presents as strip or narrow strip;Single mouth bar presents as tongue;The spatial superposed relationship of single microfacies sand include isolation type,superposition type and fold type.The remaining oil controlled by single microfacies distribute in the edge of single river or single estuary dam.The distribution of remaining oil controlled by accretionary terrane in mouth bar depends on their combination pattern :while the mouth bar presents as a single up-coarse rhythm,without interlayer in it,it is difficulty to remaining oil in the sand;while the mouth bar presents as compound rhythm of coarse-upward with even,the remaining oil tends to be in the bottom of the sand;while in the cases of coarse-upward and fining-upward compound rhythm and even rhythm,the remaining oil tends to be at the top of the sand.