Xu Zhengxiao, Li Binfei, Zhao Haiyang, He Long, Liu Zhiliang, Chen Danqi, Yang Huiyu, Li Zhaomin
School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China.
Key Laboratory of Unconventional Oil & Gas Development, China University of Petroleum (East China), Ministry of Education, Qingdao 266580, China.
ACS Omega. 2020 Jul 23;5(30):19092-19103. doi: 10.1021/acsomega.0c02434. eCollection 2020 Aug 4.
In recent years, studies conducted on foam stabilization have focused on nanoparticles by generating strong adsorption at the interface to stabilize the foam under harsh reservoir conditions. Meanwhile, the selection of a gas source is also of great importance for foam performance. In this study, a mixed system of surfactants was selected, and the foamability and foam stability of nitrogen and methane were evaluated according to the improved jet method. After adding modified SiO nanoparticles, the foam-related parameters were analyzed. The plugging abilities of the different foams were compared through core-flooding experiments, and the oil displacement effects of the different foams were compared through microfluidic experiments. The results show that the amphoteric surfactant betaine has an excellent synergistic effect on the anionic surfactant SDS. The methane foam produced using the jet method has a larger initial volume than the nitrogen foam, but its stability is poor. The half-life of the nitrogen foam is about two times that of the methane foam. After adding 1.0 wt % SiO nanoparticles to the surfactant solution, the viscosity and stability of the formed foam improve. However, the maximum viscosity of the surfactant nanoparticle foam (surfactant-NP foam) is 53 mPa·s higher than that of the surfactant foam. In the core-flooding experiment, the plugging performance of the methane foam was worse than that of the nitrogen foam, and in the microfluidic experiment, the oil displacement abilities of the methane foam and the nitrogen foam were similar. The plugging performance and the oil displacement effect of the foam are greatly improved by adding nanoparticles. The surfactant-NP foam flooding has a better oil displacement effect and can enhance the recovery factor by more than 30%. Under actual high-pressure reservoir conditions, although the stability of the methane foam is weaker than that of the nitrogen foam, some methane may be dissolved in the crude oil to decrease the viscosity after the foam collapses, which leads to the methane foam being the preferred method in oilfields.
近年来，关于泡沫稳定性的研究主要集中在纳米颗粒上，通过在界面处产生强烈吸附来在恶劣的油藏条件下稳定泡沫。同时，气体源的选择对泡沫性能也至关重要。在本研究中，选择了一种表面活性剂混合体系，并根据改进的喷射法评估了氮气和甲烷的发泡性和泡沫稳定性。添加改性二氧化硅纳米颗粒后，分析了与泡沫相关的参数。通过岩心驱替实验比较了不同泡沫的封堵能力，并通过微流控实验比较了不同泡沫的驱油效果。结果表明，两性表面活性剂甜菜碱对阴离子表面活性剂十二烷基硫酸钠具有优异的协同作用。采用喷射法制备的甲烷泡沫初始体积比氮气泡沫大，但其稳定性较差。氮气泡沫的半衰期约为甲烷泡沫的两倍。在表面活性剂溶液中添加1.0 wt%的二氧化硅纳米颗粒后，形成的泡沫的粘度和稳定性提高。然而，表面活性剂-纳米颗粒泡沫（surfactant-NP泡沫）的最大粘度比表面活性剂泡沫高53 mPa·s。在岩心驱替实验中，甲烷泡沫的封堵性能比氮气泡沫差，在微流控实验中，甲烷泡沫和氮气泡沫的驱油能力相似。添加纳米颗粒可大大提高泡沫的封堵性能和驱油效果。表面活性剂-纳米颗粒泡沫驱油具有更好的驱油效果，可提高采收率30%以上。在实际的高压油藏条件下，尽管甲烷泡沫的稳定性比氮气泡沫弱，但泡沫破裂后一些甲烷可能会溶解在原油中降低粘度，这使得甲烷泡沫成为油田中的首选方法。
