Research on interlayers of braided river reservoirs based on discontinuous boundary identification:A case study of Guantao Formation in P Oilfield,Bohai Sea
Braided river reservoirs with frequent channel cutting and overlapping are developed in P Oilfield in the Bohai Sea,and the development of interlayers in the reservoir has been revealed by drilling,resulting in a large difference in water-flooding state and productivity after drilling.Fine description and accurate characterization of interlayers are the keys to tapping the potential of remaining oil.The characteristics and causes of interlayer distribution in P Oilfield were analyzed,and it was considered that interlayer distribution had a good correlation with configuration boundary,so an interlayer characterization method based on discontinuous boundary identification was proposed.The boundary channel,internal main channel,and internal sub-channel were identified by two-stage discontinuous boundary analysis,corresponding to the three interlayer types of composite core-beach boundary channel filling,single core-beach boundary channel filling,and serial channel filling,respectively.The quantitative discrimination criteria for each level of the channel were established,and the center line of interlayer thickness was determined.According to the side drilling data of 300 well groups in the study area,the average thickness and wingspan width of the interlayer were determined.The distribution map of interlayer thickness was plotted by means of classification interpolation and well point correction.The results show that the interlayers of the braided river reservoir in the Guantao Formation in P Oilfield are mostly distributed in the form of wide wing strips.The average thickness of the three interlayers is 3,2,and 1 m,and the average wingspan width is 100,50,and 25 m,respectively.The method presented in this paper is applied to the L50 Formation in the C10 well area for detailed study,and the results of interlayer description can effectively guide the exploitation of remaining oil potential.
discontinuous boundarybraided river reservoircenter line of interlayer thicknesswingspan widthremaining oil distribution
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