Effect of Charge Density of Reverse Emulsion Breaker on Demulsification Performance for Steam-Assisted Gravity Drainage (SAGD) Emulsions under High Temperature and High Pressure

Abstract

Reverse emulsion breakers (REBs) play a crucial role in the demulsification of complex water-in-oil-in-water (W/O/ W) emulsions in steam-assisted gravity drainage (SAGD) production of oil sands. Developing effective REBs remains challenging due to the poor understanding of influencing factors and demulsification mechanisms. In particular, despite the recognition of the vital role of charge density of the REBs in their demulsification performance, the available literature is limited. Herein, we investigated the correlation between the charge density of commercial REBs and their demulsification performance for complex emulsions under simulated SAGD operation conditions (100−200 °C and 0.3−1.4 MPa) by employing an in-house-built bottle test system. It is demonstrated that a high charge density of the REBs not only promotes the qualities of produced water and oil but also significantly accelerates the speed of oil/water phase separation. At the microscale, the REB with a high charge density is capable of reducing the amount and size of residual oil droplets in produced water. The interactions of the species involved during the demulsification process were investigated by employing multiple techniques including optical microscopy imaging, ζ potential measurement, and dynamic light scattering. The results suggest that the cationic REBs are adsorbed at the oil/water interface, neutralize negative surface charge of oil droplets, and replace interface-active species originally present at the oil/water interface. Multilayer adsorption of REBs may be generated after demulsification, and the adsorbed REBs could partially desorb from the surface of oil droplets with increasing temperature. This work has delineated the influence of the charge density of REBs on their demulsification performance and improved the fundamental understanding of the interactions of the constituent species in SAGD emulsions and REBs, which provides useful information on the development and applications of efficient and cost-effective chemicals in oil sands exploitation and emulsion treatment.

A Critical Review of Reservoir Simulation Applications in Key Thermal Recovery Processes: Lessons, Opportunities, and Challenges

“…Rocha et al (2018) found that the least soluble fraction of asphaltenes acted as a stabilized agent for water in bitumen emulsions . Wang et al (2020) measured a charge density of a reverse emulsion breaker to find a suitable agent to break emulsion in SAGD operation conditions . Velayati and Nouri in 2020 presented a review on emulsification and emulsion flow during a SAGD process, which covered emulsification mechanisms, emulsion stability, emulsion properties, and controlling factors on emulsion formation …”

“…139 Wang et al (2020) measured a charge density of a reverse emulsion breaker to find a suitable agent to break emulsion in SAGD operation conditions. 140 Velayati and Nouri in 2020 presented a review on emulsification and emulsion flow during a SAGD process, which covered emulsification mechanisms, emulsion stability, emulsion properties, and controlling factors on emulsion formation. 141 Steam injection is an effective way to reduce oil viscosity, but it also raises the reservoir temperature leading to H 2 S and CO 2 generation by aquathermolysis.…”

Oxidation of Heavy Oil Using Oil-Dispersed Transition Metal Acetylacetonate Catalysts for Enhanced Oil Recovery

“…To deal with inaccessible placements or uncommon compositions of unconventional resources, innovative production techniques and novel approaches seem to be necessary. For heavy and extra-heavy oil reservoirs, thermal methods are primarily used methods due to their capability to decrease oil viscosity and increase its mobility. − Generally, thermal EOR (ThEOR) methods consist of steam-assisted gravity drainage, , cyclic steam stimulation, , and in situ combustion (ISC) , methods. However, a literature review on ThEOR methods proposed the ISC technique to be one of the most energy-efficient processes which can improve the properties of heavy oil through decreasing heavy components such as asphaltene and resins. , In the ISC process, air/oxygen is injected into the reservoir to generate heat by burning a portion of the hydrocarbons that leads to a heat front in the reservoir, which reduces the viscosity of heavy and extra-heavy oils and sometimes achieves conditions for in situ upgrading, thereby EOR .…”

“…For heavy and extra-heavy oil reservoirs, thermal methods are primarily used methods due to their capability to decrease oil viscosity and increase its mobility. 1−3 Generally, thermal EOR (ThEOR) methods consist of steam-assisted gravity drainage, 4,5 cyclic steam stimulation, 6,7 and in situ combustion (ISC) 8,9 methods. However, a literature review on ThEOR methods proposed the ISC technique to be one of the most energy-efficient processes which can improve the properties of heavy oil through decreasing heavy components such as asphaltene and resins.…”

Understanding the Properties of Bitumen Froth from Oil Sands Surface Mining and Treatment of Water-in-Oil Emulsions

“…Among the current emulsion treatment methods, e.g., microwave irradiation, centrifugation, hydrocyclone, and chemical demulsification, chemical treatment is extensively applied in consideration of its cost-efficiency and effectiveness. To promote the chemical demulsification efficiency, a special focus was generally placed on the development of effective demulsifiers by employing model emulsions. − Nevertheless, the characteristics of practical emulsions, such as compositions, particle size distribution, and component interactions, have significant and various effects on the demulsification efficiency. , The precise and comprehensive correlation between the characteristics of practical bitumen froth and the demulsification efficiency has not been fully investigated.…”