Development characteristics and dynamic prediction of near critical reservoirs——By taking Bohai BZ oilfield as an example

Due to the fact that the variation law of oil and gas in near critical state reservoirs is more complex than that in conventional reservoirs, the deviation of oil and gas recovery degree and production gas oil ratio predicted by conventional reservoir engineering method is large, and dynamic prediction is difficult. Based on the generalized material balance equation and oil-gas two-phase permeability curve under low interfacial tension, a new dynamic prediction method for near critical reservoir is established by analyzing the factors affecting the fluid characteristics and development law of near critical reservoir. The results show that the oil recovery degree and instantaneous gas oil ratio calculated by the improved new method are more in line with the actual production performance, and the prediction of oil-gas recovery law and recovery rate is more accurate because of the dual effects of dissolved gas oil ratio and volatile oil gas ratio, as well as the change characteristics of oil-gas phase permeability under low interfacial tension. The research results have certain guiding significance for the development of similar reservoirs.