Title: Experimental investigation of heavy oil recovery by continuous/WAG injection of CO₂ saturated with silica nanoparticles

Authors: Saeed Jafari; Ayub Khezrnejad; Omid Shahrokhi; Mohammad Hossein Ghazanfari; Manouchehr Vossoughi

Addresses: Department of Petroleum and Chemical Engineering, Sharif University of Technology, Tehran, Iran ' Department of Petroleum and Chemical Engineering, Sharif University of Technology, Tehran, Iran ' Department of Petroleum and Chemical Engineering, Sharif University of Technology, Tehran, Iran ' Department of Petroleum and Chemical Engineering, Sharif University of Technology, Tehran, Iran ' Department of Petroleum and Chemical Engineering, Sharif University of Technology, Tehran, Iran

Abstract: In this work, application of CO₂ saturated with silica nanoparticles in continuous/water alternating gas (WAG) injection for heavy oil recovery was investigated which has been rarely attended in the available literature. Core displacement tests were conducted to monitor heavy oil recovery in both continuous and WAG injection schemes. It has been observed that for continuous nano-saturated CO₂ injection, the oil recovery is higher than pure CO₂ injection. This observation might be explained by alteration of rock wettability to a more water-wet condition. In WAG injection scheme, water breakthrough happened later in nano-saturated CO₂ than pure CO₂ injection. This delayed water breakthrough can be caused by nano-stabilised oil in water emulsions. These oil emulsions hindered the oil recovery before breakthrough. However, recovery factor of WAG injection of nano-saturated CO₂ exceeded that of pure CO₂ as those stabilised oil emulsion were produced along with water after breakthrough. The results of this work reveal that saturation of CO₂ with silica nanoparticles can improve the microscopic efficiency of continuous CO₂ injection, while in CO₂ WAG injection this hampers oil recovery before water breakthrough. [Received: November 10, 2013; Accepted: April 25, 2014]

Keywords: WAG injection; water alternating gas; continuous gas injection; experimental; silica nanoparticles; CO2; carbon dioxide; nanotechnology; heavy oil recovery; rock wettability; oil emulsions.

DOI: 10.1504/IJOGCT.2015.067494

International Journal of Oil, Gas and Coal Technology, 2015 Vol.9 No.2, pp.169 - 179

Received: 16 Nov 2013
Accepted: 25 Apr 2014
Published online: 18 Mar 2015 *

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