Research On The Distribution Of Remaining Oil In The North-Ⅱ-west Tract Of Steam Flooding After Polymer Flooding

The experimental area is located in the east of the North-II-West Tract of North Saertu oil field in Daqing, and its well history is very complex, which is put into development in 1964, has gone through the water flooding, polymer flooding and steam flooding. The task of exploitation and adjustment is searching for and exploiting the remaining oil in present, so the next step of exploitation is finding out residual oil distribution law of PI in this area.Based on the regional geological characteristics of this experimental area, the artile cairry out fine formation correlation on PI1~PI4 by the method of reservoir correlation, that is, by combining sedimentary cycle correlation, hierarchical control and discriminating different sedimentary facies association. On the basis of regional geological background and the relationship between the well logging facies and sedimentary facies,set up log facies and work out the sublayer sedimentary microfacies units,then conduct research of micro-structure of oil formation, reservoir heterogeneity, division of flow unit.the next step is that to build structure modeling, sedimentary micro-facies and simulate porosity model, permeability model and originality oil saturation model in this area by sequential gaussian simulation algorithmwithin each facies on the basis of Sedimentary Facies Map. Afterwards, the article conduct production history match the index of the single well and the whole area.Finally, based on correlation, subdividing sedimentary facies into and modeling, the authors come to the conclusion that the remaining oil can be divided into four types:type-I-injection-production imperfection is controlled by well pattern; type-II-bad oil formation with sheet distribution is controlled by sedimentary micro facies; type-III in remained oil area is controlled by micro-structure; type-IV-bad oil distribution in thick oil reservoir is controlled by reservoir heterogeneity and B2-340-SP50, B2-341-SP49, B2-D4-P39, B2-342-SP52 are the abundance zone of remaining oil and the further exploitation.