Understanding the chemical mechanisms for low salinity waterflooding

Changhe Qiao, Russell Johns, Li Li

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

1 Scopus citations

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 publicationSociety of Petroleum Engineers - SPE Europec Featured at 78th EAGE Conference and Exhibition
PublisherSociety of Petroleum Engineers
ISBN (Electronic)9781613994573
StatePublished - Jan 1 2016
EventSPE Europec Featured at 78th EAGE Conference and Exhibition - Vienna, Austria
Duration: May 30 2016Jun 2 2016

Publication series

NameSociety of Petroleum Engineers - SPE Europec Featured at 78th EAGE Conference and Exhibition

Other

OtherSPE Europec Featured at 78th EAGE Conference and Exhibition
CountryAustria
CityVienna
Period5/30/166/2/16

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All Science Journal Classification (ASJC) codes

  • Geotechnical Engineering and Engineering Geology
  • Fuel Technology
  • Geochemistry and Petrology

Cite this

Qiao, C., Johns, R., & Li, L. (2016). Understanding the chemical mechanisms for low salinity waterflooding. In Society of Petroleum Engineers - SPE Europec Featured at 78th EAGE Conference and Exhibition (Society of Petroleum Engineers - SPE Europec Featured at 78th EAGE Conference and Exhibition). Society of Petroleum Engineers.