Abstract
The formation of water in oil (W/O) emulsion can result in flow issues in the reservoir and a high cost of demulsification throughout the water treatment process. Without treatment, the W/O emulsion takes a long time to settle, which results in blockage in porous media. CO2 has strong interaction with crude oil and so has the potential to alter the settling process of W/O emulsion. The purpose of this paper is to undertake a numerical and experimental investigation into the influence of CO2 on the emulsion stability. To anticipate the settling process of a W/O emulsion in a high-pressure environment, a mathematical model was created that included a CO2 diffusion model, a viscosity prediction model, and an emulsion settling model. A high-pressure reactor was used to model the emulsion demulsification process at three different pressure conditions and to evaluate the model's prediction capability. The results indicate that under a high-pressure CO2 atmosphere, the demulsification process of a W/O emulsion can be accelerated. The CO2 dissolution and diffusion into the oil phase might enhance the likelihood of droplets colliding, resulting in the demulsification of the W/O emulsion system. Pressure has a significant influence on the stability of the emulsion. High pressure accelerates the CO2 dissolution process and significantly reduces the time required for the emulsion system to reach equilibrium. Additionally, the oil/water ratio can affect the stability of a W/O emulsion. At the same pressure, an emulsion with a higher oil/water ratio required a shorter time to reach equilibrium and had a higher equilibrium viscosity.
NSTL
Elsevier