Title: The novel use of malonic acid-based deep eutectic solvents for enhancing heavy oil recovery

Authors: Iman Al-Wahaibi; Yahya Al-Wahaibi; Rashid Al-Hajri; Baba Jibril; Suleiman Shuwa

Addresses: Petroleum Development Oman, P.O. Box 50, Muscat 22, Oman ' Petroleum and Chemical Engineering Department, Sultan Qaboos University, P.O. Box 33, Alkhoud 123, Oman ' Petroleum and Chemical Engineering Department, Sultan Qaboos University, P.O. Box 33, Alkhoud 123, Oman ' Chemical Engineering Department, Ahmadu Bello University, Abuja, Nigeria ' Chemical Engineering Department, Ahmadu Bello University, Abuja, Nigeria

Abstract: This study investigates the potential of deep eutectic solvents (DES) to recover the residual oil left after waterflooding. For the first time to our knowledge, the effectiveness of two DESs - choline chloride-malonic acid of molar ratios 1:1 and 1:0.5 - in enhancing oil recovery was investigated. The solvents were characterised by measuring density, viscosity, conductivity and pH at different temperatures. Also, measurements of interfacial tension, wettability alteration, spontaneous water imbibition, emulsification, core flood and formation damage tests were conducted at different temperatures. The core flood tests were carried out at reservoir condition using Berea sandstone cores and fluids from the field of interest. Results showed the solvents produced 7%-14% of the residual heavy oil after brine flooding as tertiary recovery stage and without causing any formation damage. Both DESs showed better performance at higher temperatures. Wettability alteration was found to be the dominant mechanism for the oil recovery enhancement. [Received: October 4, 2015; Accepted: October 15, 2016]

Keywords: residual heavy oil; deep eutectic solvents; DES; interfacial tension; wettability alteration.

DOI: 10.1504/IJOGCT.2019.096493

International Journal of Oil, Gas and Coal Technology, 2019 Vol.20 No.1, pp.31 - 54

Received: 04 Oct 2015
Accepted: 25 Oct 2016
Published online: 05 Dec 2018 *

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