Numerical Simulation on displacement mechanism of fracture-cave reservoir surfactant-Assisted N_2 huff and puff in Tahe Oilfield

摘要

Some fracture-cave units controlled by single well in fractured-vuggy carbonate reservoirs lack natural energy, which leads to rapid decline of production and recovery. Having applied the N_2 huff and puff, Tahe Oilfield has improved their exploitation. However, the effect of N_2 injection weakens in the production process. So it is necessary to seek new method for exploitation of fractured-vuggy reservoirs. Combing with the numerical simulation, then analyzing the qualitative and quantitative influences of injection rate, injection concentration of surfactant on the recovery efficiency of isolated fracture-cave units, this paper focuses on the problem of the fractured-vuggy carbonate oil reservoir's low recovery, and also forecasts the effect of the different surfactant-Assisted N_2 huff and puff scheme, then presents the best plan in this reservoir condition and acquires the main control factors of the surfactant - assisted N2 huff and puff.