高温高盐油藏CO2驱泡沫封窜体系研究与应用

Research and application on foam plugged channeling system in high-temperature and high-salt reservoirs CO_2 flooding

针对中原油田CO2驱过程中的气窜问题,研制了耐温抗盐CO2泡沫封窜体系。该体系起泡剂选用咪唑啉类两性表面活性剂,稳泡剂选用TL3000共聚物,耐温100℃,耐盐20×104mg/L,耐钙镁5 000 mg/L。用CO2气体充气法对其性能进行了评价。评价结果表明,其半衰期达84 min,体系表面张力30.6 mN/m,界面张力0.43 mN/m,具有较低的表界面张力。可视化封堵实验观察到该泡沫体系在多孔介质中起泡性能较好。岩心封堵实验表明,该体系封窜能力较强,阻力系数达到25.63,残余阻力系数为9.4。15井次的现场试验结果表明,该体系对CO2气窜有较好的封窜能力,为目前CO2驱过程中控制气窜问题提供了新的有益尝试。

aiming at the gas channeling problem in CO2 flooding in Zhongyuan oilfield, CO2 foam plugged channeling system with heat resistance and tolerance to salt was developed. The amphoteric surfactant imidazoline was selected to be foaming agent and copolymer TL3000 was foam stabilizer in this system. The evaluation results in laboratory showed that the prescription had excellent synthetically function： resistant temperature 100~C, salt tolerance 20~ 104 mg/L, calcium and magnesium resistance 5 000 mg/L. The formula was evaluated by CO2 gas inflation method, and the results showed that its half-life extends to 84 min, and surface tension is 30.6 mN/m while interfacial tension is 0.43 mN/m, and both of them are relatively lower. Visualization plugging experiment showed that this foam system has excellent foaming ability in porous medium. The core plugging test illustrated its strong plugged channeling ability with coefficient of resistance up to 25.63 and residual resistance factor of 9.4. 15 well times field application were launched, and the results indicated that the great plugging channeling capacity for CO2 gas channeling has provided a newly favorable attempt in controlling gas channeling problem in CO2 flooding.