Experimental investigation of liquid-CO2 and CO2-emulsion application for enhanced heavy oil recovery

Alireza Emadi, Mehran Sohrabi Sedeh, Seyed Amir Farzaneh, Shaun Ireland

Research output: Chapter in Book/Report/Conference proceedingConference contribution

9 Citations (Scopus)

Abstract

CO2 Injection in heavy oil reservoirs improves oil recovery and at the same time may reduce some of the environmental concerns associated with heavy oil recovery by thermal methods. Depending on the reservoir conditions and oil properties, viscosity reductions of up to two orders of magnitude may be achieved as a result of CO2 dissolution in heavy oil. However, adverse viscosity ratio which results in viscous fingering and early breakthrough of CO2 is a challenge for application of CO2 in heavy oil reservoirs. Therefore, CO2 injection needs to be combined or augmented by other displacement mechanisms (e.g. waterflood, foam injection) to efficiently displace the heavy oil diluted with CO2. In our previous papers, the micro-scale displacement efficiency and mechanisms involved in CO2 and CO2-foam injection in heavy oil systems were investigated and presented through vivid micromodel images. This paper presents the results of a series of coreflood experiments performed to evaluate the potential of liquid-CO2 and CO2-emulsion injection in a heavy oil reservoir.

The coreflood results show a very good performance for CO2 injection. An ultimate recovery of around 70 %OOIP as a result of secondary and tertiary CO2 injection was achieved which was twice the recovery obtained by waterflood in this heavy crude oil. This substantial recovery improvement was a consequence of a massive viscosity reduction (up to 97.5% of the original oil viscosity) at reservoir conditions. Co-injection of liquid CO2 and a selected surfactant also resulted in in-situ formation of a very stable CO2-emulsion which reduced mobility of injected CO2 by three orders of magnitude in presence of oil. In-situ generation of CO2-emulsion as evident from an increased in the pressure drop across the core was observed even at high oil saturation of up to 50%. The results of this work show significant potentials for immiscible CO2 and CO2-emulsion injection as an effective enhanced heavy oil recovery technique.
Original languageEnglish
Title of host publication75th European Association of Geoscientists and Engineers Conference and Exhibition 2013
Subtitle of host publicationChanging Frontiers: Incorporating SPE EUROPEC 2013
Place of PublicationHouten
PublisherEAGE Publishing BV
Pages1933-1950
Number of pages16
ISBN (Electronic)9781613992548
ISBN (Print)9781629937915
DOIs
Publication statusPublished - 2013
Event75th EAGE Conference and Exhibition 2013 - London, United Kingdom
Duration: 10 Jun 201313 Jun 2013

Conference

Conference75th EAGE Conference and Exhibition 2013
Abbreviated titleSPE EUROPEC 2013
CountryUnited Kingdom
CityLondon
Period10/06/1313/06/13

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