Title: An analytical model for dissolution of deposited asphaltene during CO₂ injection from the porous media

Authors: Ilyas Khurshid; Jonggeun Choe

Addresses: Department of Chemical and Petroleum Engineering, UAE University, Al-Ain 15551, UAE ' Department of Energy Resources Engineering, Seoul National University, Seoul, 151-744, South Korea

Abstract: Carbon dioxide (CO₂) based enhanced oil recovery (EOR) technique has a couple of benefits: mitigate CO₂ emissions and increase recovery of oil from a reservoir. However, oil recovery is dependent on the composition of crude oil. Saturate-aromatic-resin-asphaltene (SARA) analysis shows that crude oil is composed of saturates, aromatics, resins, and asphaltene. It is found that asphaltene poses complex and severe formation damage problems and reduces the recovery of oil. After primary production with the change in pressure, temperature, and composition, the asphaltene may flocculate, precipitate and deposit in porous media. In this study, an analytical model is derived for the dissolution of deposited asphaltene. The derived model is used to develop a simulator that solves the dissolution of deposited asphaltene from porous media. The results of the derived model show good match with the laboratory results and also found important parameters that may lead to asphaltene dissolution. Our results show that asphaltene dissolution is affected by asphaltene concentration and its solubility, properties of host rock (heterogeneities), force of adhesion, and CO₂ injection rate and period. The model does not consider CO₂-rock chemical reactions in porous media. However, its consideration can increase reservoir porosity and permeability. [Received: May 24, 2017; Accepted: December 24, 2017]

Keywords: CO₂ injection; asphaltene dissolution; asphaltene deposition; formation damage; enhanced oil recovery; EOR.

DOI: 10.1504/IJOGCT.2018.093143

International Journal of Oil, Gas and Coal Technology, 2018 Vol.18 No.3/4, pp.338 - 352

Received: 24 May 2017
Accepted: 24 Dec 2017
Published online: 10 Jul 2018 *

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