Study On Main Controlling Factors And Development Measures Of Residual Oil In GD High Water-cut Reservoir

With many years of water injection development,most of China's oil fields have entered the stage of high water-cut or even the extremely high water-cut.The distribution of residual oil is characterized by “whole dispersion and local enrichment”.According to the current status of oilfield development,the factors affecting the residual oil are analyzed,the main controlling factors of residual oil in high water-cut oilfields are clarified,and scientific and reasonable potential tapping measures are proposed to realize “adjusting the streamline”,“controlling water and stabilizing oil”,and “exploiting potential and enriching areas”.That is extremely important for guiding the development of high water-cut reservoirs,improving oil recovery,and obtaining economic benefits from oilfield.In view of the problem of “fixed injection streamline,heterogeneous flooding and unreasonable liquid production structure” in the GD high water-cut reservoir of Sheng Li Oilfield,the development of the reservoir and rhythm of the target reservoir were fully considered,which is based on the actual geological and development profiles.According to dynamic and static data,a actual geological and numerical model was established by using reseriovrs engineering and numerical simulation methods.Comprehensively use the results of core test,seismic interpretation,logging interpretation,production dynamics and numerical simulation to analyze the control effects of single factors including geological factors and development factors.Comprehensive multi-factor analysis obtain the main controlling factors of residual oil.Geological factors include sedimentary microfacies,lateral connectivity,interlayer permeability difference,physical interlayer,and sand body superposition;Development factors include development well pattern,displacing water multiple,and injection-production correspondence.Based on the main control factors of GD high water-cut reservoirs,the distribution of residual oil-rich areas and the status of development problems,the targeted potential tapping measures were proposed.The prediction and effect verification of the potential tapping scheme were carried out.The results show that the main controlling factors of residual oil in GD high water-cut reservoirs are the development well pattern,physical interlayer and interlayer permeability difference.The residual oil-rich areas are mainly concentrated in oil wells,physical interlayers shielding and the top of the positive rhythm thick oil layer.The adjustment of well pattern,the optimization of the development technology policy and the side-tracking horizontal well were proposed respectively.By designing six different well patterns adjustment schemes,it is finally determined that the well pattern of the two sets of thinning and alternating pulses is optimal on the basis of the actual well pattern.The optimum perforation method,pulse period,liquid sampling speed and injection-production ratio are avoiding bottom 2/3 of oil and water well,1year,200% liquid extraction,and 0.96,which are obtained through technical policy optimization;The optimal choice of side-tracking well is determined by the optimization of side-tracking horizontal well in the old well.The vertical position and level of the best sidetracking horizontal section and segment direction,horizontal section length and optimum horizontal well production are also given.After the production forecast of the potential tapping countermeasure,the results show that the development effect is remarkable.The change of the streamline distribution before and after the adjustment also verifies the rationality of the potential tapping scheme,which has guiding significance for the potential tapping of the residual oil in the same type of high water-cut reservoir.