Emulsification and improved oil recovery with viscosity reducer during steam injection process for heavy oil

• Published in: Journal of industrial and engineering chemistry (Seoul, Korea) 2018, 61(0), , pp.348-355
• Main Authors: Wu, Zhengbin, Huiqing, Liu, Wang, Xue, Zhang, Zequan
• Format: Article
• Language: English
• Subjects: EOR; Heavy oil; O/W emulsions; Steam injection; Viscosity reducer; 화학공학
• ISSN: 1226-086X; 1876-794X
• DOI: 10.1016/j.jiec.2017.12.033

With the injection of steam+VR, plenty of small emulsions generated near the inlet. The emulsions were newly formed, so that they were relatively smaller and not very stable. As the steam+VR was injected continuously, some emulsions coalesced into bigger emulsions and with the further migration of emulsions in the porous media, the emulsion size became small due to the enhancement of shear action. [Display omitted] •A kind of anionic–nonionic viscosity reducer is proposed.•Low salinity and high water–oil ratio lead to stable oil-in-water emulsions.•The entrapment of oil-in-water emulsions is an important mechanism for sweep efficiency improvement.•The addition of viscosity reducer improves steam absorption profile and oil–steam ratio in heterogeneous reservoir. An anionic–nonionic surfactant was proposed as viscosity reducer (VR) for study. Firstly, bulk emulsion behavior was investigated to optimize the emulsification process. Secondly, core flooding tests were carried out to evaluate the synergistic effect of VR and steam for improved heavy oil recovery, as well as emulsion properties along the distance. Thirdly, a 2D microvisual study was performed to illustrate emulsion migration and plug property in porous media. Finally, VR assisted steam stimulation was conducted for field application, and gained satisfactory result both in oil–steam ratio and oil recovery, providing an alternative for enhancing oil recovery in similar steamflooded reservoirs.