An Experimental Investigation of Immiscible Carbon Dioxide Interactions with Crude Oil: Oil Swelling and Asphaltene Agitation

Abstract

Immiscible carbon dioxide (CO2) injection is a method used to increase oil recovery from oil reservoirs. Several interactions will occur between the CO2 and the crude oil during immiscible CO2 injection. While some of these interactions may be favorable, others can actually deter oil recovery and cause serious damage to the producing formations and facilities. This research studies the main factors impacting oil swelling, which is the main favorable mechanism that increases oil recovery during immiscible CO2 injection in oil reservoirs. The research also investigates the impact of the studied factors on asphaltene instability and deposition and its impact on oil recovery reduction. The impact of varying CO2 injection pressure, temperature, and crude oil viscosity on oil swelling, asphaltene instability, and oil recovery is studied. Crude oil with viscosity of 460, 267, and 67 cp was used in this study. Based on the experiments, results showed that oil swelling increased with the increase in pressure and decrease in oil viscosity, however, it also decreased with the increase in temperature. When testing the effect of these factors on asphaltene stability in the crude oil it was found that asphaltene damage decreased with the increase in pressure and decrease in oil viscosity and increased with the increase in temperature. Based on this, high pressure and low viscosity oils are more favorable for immiscible CO2 injection to increase oil recovery and also avoid severe asphaltene damage. At higher temperature, precautionary measures should be taken during CO2 injection to avoid asphaltene damage.

Department(s)

Geosciences and Geological and Petroleum Engineering

Research Center/Lab(s)

Center for Research in Energy and Environment (CREE)

Keywords and Phrases

Asphaltenes; Carbon dioxide; Crude oil; Petroleum reservoirs; Viscosity, Asphaltene instability; Asphaltene stability; Crude oil viscosity; Experimental investigations; Increase in pressure; Injection pressures; Precautionary measures; Research studies, Petroleum reservoir engineering

International Standard Serial Number (ISSN)

0016-2361

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2020 Elsevier Ltd, All rights reserved.

Publication Date

01 Jun 2020

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