After a long period of water injection and development,the oilfield enters the high water-cut stage,and the production decreases rapidly and even stops.Re-understanding the distribution law of remaining oil in the stopped production reservoirs with the high water-cut can effectively improve the recovery efficiency of old oilfields.For this reason,a plate physical simulation experiment was carried out to study the mechanism of secondary enrichment of residual oil by using the distribution of the oil saturation field.At the same time,combined with a numerical simulation study,the distribution law of remaining oil in the high position area was verified,and the main controlling factors were analyzed.The results show that the residual oil is affected by the residual resistance pressure difference and imbibition,and the secondary enrichment is mainly distributed in the peripheral areas of the injection-production line and the high areas with low permeability.The influencing factors and technical limits affecting the secondary accumulation of remaining oil are determined,i.e.,the secondary exploitation can be carried out in a stopped production reservoir with the high water cut if the reservoir meets the conditions such as the stoppage time exceeds 36 months,the formation dip angle is more than 20°,the plane permeability difference is greater than 2,and the permeability is more than 50×10-3μm2.
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