新疆风城Z32稠油油藏注气辅助蒸汽驱实验研究及矿场应用

Experiment on steam flooding assisted by gas injection in Z32 heavy oil reservoir in Fengcheng of Xinjiang and its application

稠油油藏注蒸汽开发后期,汽窜严重,开发效果逐年变差,急需探讨改善蒸汽驱效果的相关技术,针对新疆油田风城Z32齐古组油藏稠油特点,研究了注CO_(2)辅助蒸汽驱改善开发效果的可行性。在稠油油藏注蒸汽开采过程中,注入CO_(2)、N_(2)或烟道气,可以使原油体积膨胀,增加地层弹性能量,降低原油黏度,改善原油的流动能力。利用高温高压原油配样器和岩心流动实验装置,测定了不同类型注入气对稠油的膨胀、降黏效果:注入CO_(2)、N_(2)和模拟烟道气分别可使原油体积膨胀约10%~40%、2%~10%、4%~16%,黏度降低27.3%~82.9%、4.3%~18.5%、10.2%~45.8%,CO_(2)、N_(2)和模拟烟道气分别能够提高采收率5.83%、3.08%、3.75%,因此,推荐选用CO_(2)作为注入介质。现场应用实践表明,CO_(2)辅助蒸汽驱措施后,井组日产油由26.6 t上升至36.2 t,油汽比由0.174上升至0.206,增油1 158 t,取得了显著的经济效益,为该技术的规模应用提供了参考依据。

In the later stage of heavy oil reservoir development by steam injection,the steam channeling is serious and the development effect gets worse year by year.So it is urgent to apply relevant technologies to improve steam flooding performance.According to the characteristics of the heavy oil reservoir in Z32 Qigu Formation in Fengcheng Oilfield,the feasibility of steam flooding assisted by CO2 injection to improve the development effect has been studied.In the process of steam injection in heavy oil reservoir,the injection of CO2,N2 or flue gas can make crude oil swell,increase formation elastic energy,reduce viscosity of crude oil and improve oil flow capacity of crude.The swell and viscosity reduction effects of different types of injected gas on heavy oil have been measured by high temperature and high pressure crude oil sampler and core flow experiment device.The volume expansion of crude oil is about 10%~40%,2%~10%and 4%~16%by injecting CO2,N2 and simulated flue gas respectively,the viscosity is reduced by 27.3%~82.9%,4.3%~18.5%and 10.2%~45.8%,respectively,and the oil recovery is enhanced by 5.83%,3.08%and 3.75%,respectively.Therefore,CO2 is recommended as the injection medium.Field application shows that after the new technology is implemented,the daily oil production of the well group increases from 26.6 t to 36.2 t,the oil steam ratio increases from 0.174 to 0.206,and the total oil production increases by 1158 t.Remarkable economic benefits are obtained,which provides references for the scale application of this new technology.