Molecular Understanding of Enhanced Hydrocarbon Recovery Processes: Role of Local Self-Diffusion Coefficients of Complex Mixtures

Author(s)

Santos, Mirella S. ; Hamza, Muhammad ; Franco, Luis F. M. ; Castier, Marcelo ; Economou, Ioannis G.

• Document type: Journal article
• Source: ENERGY & FUELS; v. 36, n. 15, p. 10-pg., 2022-07-19.

Abstract

Reducing carbon dioxide emissions in an attempt to control global warming is a critical issue being addressed at global level today. One method of regulating the amount of CO2 in the atmosphere is by reinjecting CO2 into reservoirs, thus in turn also improving the overall recovery of oil and gas. This is an enhanced oil/gas recovery technique which has received a lot of attention in industry. In this work, a computational study of the phenomena that allow for improved hydrocarbon recovery using CO2 injection into reservoir pores is presented, analyzing the effect of fluid composition, concentration, moisture, and the pore mineral. Furthermore, the ways in which fluid diffusivity behaves at the center of the pore as well as toward the pore walls are explored in detail. In this work, a methodology to compute self-diffusion coefficient is applied by obtaining the residence time from the integration of the survival probability, allowing the calculation of the local self-diffusion coefficient in areas of interest as opposed to the global self-diffusion coefficient obtained from the commonly used Einstein's relation. Results indicate that all studied characteristics of a system have a significant effect on the mobility and the configuration of the fluid within the pore. Furthermore, these characteristics have a greater pronounced effect on the diffusivity at the center of the pore and a lesser effect in the region near the wall. Finally, the effect of small quantities of water in the mixture is examined. (AU)

• FAPESP's process: 18/02713-8 - Molecular dynamics of confined fluids: equilibrium and transport properties
• Grantee: Luís Fernando Mercier Franco
• Support Opportunities: Research Grants - Young Investigators Grants