Understanding the chemical mechanisms for low salinity waterflooding

C. Qiao, R. T. Johns, J. Li

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

Abstract

Low salinity water (LSW) is reported to improve oil recovery (IOR) significantly in sandstone and carbonate core experiments. Ranges of IOR vary significantly depending on the chemical composition of brine, oil and cores. We previously developed a process-based and predictive model that explicitly includes the chemical interactions between crude oil, brine, and the carbonate surface that alter rock wettability. In this research, we improve the developed model to include explicitly the acid/base interaction and ion-binding interaction of crude oil adsorption. The wettability alteration is quantified by the surface concentrations of adsorbed carboxylic acids, which is a result of aqueous and surface reactions. The total concentrations of aqueous and surface species are varied individually and together over a large range while precipitation constraints are also included. The wettability is for a variety of brine compositions used in experiments. The wettability depends strongly on the concentration of Ca2+, Mg2+ and SO42, as well as the total salinity. Including the acid/base interaction can explain the wettability alteration trend when Ca2+, Mg2+ and SO42 concentrations are significant. Including the ion-binding through Ca2+ can better explain the wettability alteration trend when diluted formation water or seawater is injected. We can reproduce the wettability alteration trend reported in experiments from different sources by combining the acid/base and ion-binding mechanisms and considering the irreversibility of the carboxylic adsorption reactions.

Original languageEnglish (US)
Title of host publication78th EAGE Conference and Exhibition 2016
Subtitle of host publicationEfficient Use of Technology - Unlocking Potential
PublisherEuropean Association of Geoscientists and Engineers, EAGE
ISBN (Electronic)9789462821859
DOIs
StatePublished - 2016
Event78th EAGE Conference and Exhibition 2016: Efficient Use of Technology - Unlocking Potential - Vienna, Austria
Duration: May 30 2016Jun 2 2016

Publication series

Name78th EAGE Conference and Exhibition 2016: Efficient Use of Technology - Unlocking Potential

Other

Other78th EAGE Conference and Exhibition 2016: Efficient Use of Technology - Unlocking Potential
CountryAustria
CityVienna
Period5/30/166/2/16

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology

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  • Cite this

    Qiao, C., Johns, R. T., & Li, J. (2016). Understanding the chemical mechanisms for low salinity waterflooding. In 78th EAGE Conference and Exhibition 2016: Efficient Use of Technology - Unlocking Potential (78th EAGE Conference and Exhibition 2016: Efficient Use of Technology - Unlocking Potential). European Association of Geoscientists and Engineers, EAGE. https://doi.org/10.2118/180138-ms