Reservoir remaining oil distribution characteristics and influencing factors analysis of fracture-cavity carbonate reservoirs in Tahe oilfield

By using a variety of technical means,the remaining oil distribution characteristics and influencing factors analysis has been carried out.In combination with laboratory experiments,dynamic and static analysis,numerical simulation methods,analytical technique of remaining oil occurrence mode in fracture-cavity carbonate reservoir has been established and it reveals 5 modes,including remaining oil in trap,in the top of karst cave after water flooding,in reservoir space without well control,in various reservoir spaces with severe energy shortage and residual oil film after water sweeping.Combined with laboratory experiments and numerical simulation,the analysis of fracture,karst cave,reservoir space types,well types,working system and the influence of injection-production ratio on residual oil has been carried out.The results indicate karst cave is the main reservoir space and when the well is drilled on karst cave,the production effect is the best.On the whole,fractures,karst caves and development factors have different influence on remaining oil,therefore,various factors should be considered in remainingoil analysis.