Abstract
Abstract Water based EOR by wettability alteration is of interest among the oil companies because of economic and environmental reasons. It is well known that seawater acts as a wettability modifier in carbonate reservoirs, and the seawater can even be improved as a smart EOR fluid by removing Na + and Cl − ions, and spiking this NaCl-depleted seawater with SO 4 2 - ions. In this paper we have addressed the degree of seawater modification needed to achieve reasonable improvements in oil recovery in spontaneous imbibition processes at 90 °C. Compared to ordinary seawater as imbibing fluid, more than 90% of the NaCl content must be removed in order to increase the oil recovery by 7–8% OOIP. Furthermore, compared to seawater depleted in NaCl, the oil recovery could be increased by 10% OOIP by spiking the NaCl depleted seawater with sulfate, 3–4 times the sulfate concentration present in seawater. The increased efficiency of modified seawater as a smart EOR fluid in carbonate is discussed in terms of a decrease in the ionic density of the double layer close to the positively charged calcite surface.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
