Research Of Profile Control In Cyclic Steam And Flue Gas Co-stimulation Well

The cyclic steam and flue gas co-stimulation refers to the injection of both nitrogen and carbon dioxide mixed with the high-temperature water steam,in order to further improve the thermal recovery by the synergistic effect of nitrogen and carbon dioxide,which has been applied in Xinjing,Liaohe,Daqing and Bohai oil field and has arrived a very good effect.However,due to the non-condensing properties of the injected gas in the cyclic steam and flue gas co-stimulation,it is more likely to occur gas channeling problem compared with cyclic steam stimulation.Gas channeling caused gas wells to shut down,seriously affected the development of oil field effect.With the gas channeling problems encountered by the Bohai Oilfield during the cyclic steam and flue gas co-stimulation,firstly,the influence of reservoir geological factors and well factors on the gas channeling problems between horizontal wells are studied by numerical simulation based on the conceptual model.The main controlling factors of the cyclic steam and flue gas co-stimulation are clarified.Secondly,according to the need of profile control in cyclic steam and flue gas co-stimulation,the gel blocking agent formula was optimized by laboratory experiments,and the injection,plugging performance and the effect of enhanced oil recovery were evaluated.Finally,based on an actual reservoir geological model in the Bohai oil field,the profile control effect of the gel plugging agent in the process of the cyclic steam and flue gas co-stimulation was evaluated by numerical simulation.The numerical simulation shows that the thickness of pay zone,longitudinal heterogeneity,plane heterogeneity and horizontal well spacing are the most important factors influencing gas channeling;The laboratory experiments show that the temperature resistance of gel blocking agent is around 150??The single sand pack experiments show the plugging rate of gel is more than 98%;The parallel sand tube experiments show that the higher the permeability difference(<10),the better the profile improvement,and the oil recovery is increased between 24.83% and 26.16% with gel plugging measures.The numerical simulation results of actual reservoir geological model show that the oil production increased significantly after gel injection.