Effect of Sodium Citrate and Calcium Ions on the Spontaneous Displacement of Heavy Oil from Quartz Surfaces

• Published in: Journal of physical chemistry. C Vol. 124; no. 38; pp. 20991 - 20997
• Main Authors: Xiang, Bailin, Li, Rui, Liu, Bo, Manica, Rogerio, Liu, Qingxia
• Format: Journal Article
• Language: English
• Published: American Chemical Society 24-09-2020
• Subjects: C: Surfaces, Interfaces, Porous Materials, and Catalysis
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.0c06338

The dynamic displacement of heavy oil from solid surfaces by water plays a significant role in the oil recovery process. In this work, a bitumen–water–quartz system was applied to study the effect of sodium citrate (Na3Cit) and calcium ions (Ca2+) on the dynamic displacement of bitumen from quartz surfaces. It was found that the addition of Ca2+ slowed down the bitumen displacement rate and generated daughter droplets during the receding process. In contrast, the presence of Na3Cit not only accelerated the displacement of bitumen from quartz surfaces but also led to a smaller water contact angle at the end of the experiments. Moreover, Ca2+ ions were chelated by the added Na3Cit, which counterbalanced the detrimental effect of Ca2+ on the bitumen displacement. The reduced interfacial tension of the bitumen–water interface and the increased negative charges on both bitumen and silica surfaces by Na3Cit were considered as the reasons for the improved bitumen displacement process. To better understand the underlying physics, both the hydrodynamic (HD) model and the molecular kinetic (MK) model were employed to analyze the dewetting dynamics of heavy oil from quartz surfaces under the effect of Ca2+ and Na3Cit.