浅层稠油油藏CO_(2)辅助蒸汽开发机理与效果研究

Study on Mechanism and Performance of Carbon Dioxide Assisted Steam in Shallow Heavy Oil Reservoir

研究了CO_(2)辅助蒸汽开发浅层稠油的机理和效果。结果表明:CO_(2)溶于稠油后能增加原油体积系数、降低原油黏度和界面张力,增加油相相对渗透率以及降低残余油饱和度;蒸汽吞吐过程中增加CO_(2)辅助,能够有效弥补地层亏空,维持吞吐压力,可使吞吐采收率提高16.9个百分点。蒸汽驱后期采用CO_(2)与蒸汽交替注,能够产生水气交替作用,有效延缓注入压力快速下降,提高波及效率,可使原油采收率提高23.3个百分点,增油效果显著。

In this paper,mechanism and performance of carbon dioxide assisted steam were studied for the development of shallow heavy oil.The results indicate that CO_(2)dissolving in heavy oil can increase oil volume factor,reduce oil viscosity and interfacial tension,increase oil phase relative permeability and reduce residual oil saturation.During the steam stimulation process,addition of CO_(2)enables to fill up the formation deficit and maintain soaking pressure effectively.The oil recovery factor of steam stimulation increased by 16.9 percentage points.In the late stage of steam flooding,application of CO_(2)alternating with steam flooding can produce water and gas alternation effect,which can effectively delay the drop of injection pressure and improve sweep efficiency.The oil recovery factor increased by 23.3 percentage points,showing the remarkable performance in heavy oil extraction.