Drivers of pH increase and implications for low salinity effect in sandstone
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© 2018 Elsevier Ltd. Low salinity water flooding appears to be a cost-effective and environmentally friendly means to shift wettability of oil/brine/rock system towards more water-wet, thus improving hydrocarbon recovery. While the contribution of kaolinite (edge-charged clays) on low salinity effect has been extensively investigated, how basal-charged clays (e.g., illite, smectite, and chlorite) contributing to the low salinity effect remains unclear. We thus hypothesize that low salinity water facilitates ion exchange in the presence of basal charged clays, thus lifting off oil films from pore surfaces. To test the hypothesis, we performed a geochemical study using PHREEQC in light of double layer diffuse theory. We quantitatively interpreted the pH increase and low salinity effect from corefloods conducted by RezaeiDoust et al. [RezaeiDoust A, Puntervold T, Austad T. Chemical verification of the EOR mechanism by using low saline/smart water in sandstone. Energy & Fuels. 2011;25(5):2151–62.]. We demonstrate that low salinity water triggers a pH increase at the presence of basal-charged clays, thus a more water-wet because of ion exchange. We therefore expand the application envelope of low salinity water flooding to reservoirs with basal-charged clays.
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Xie, Sam; Liu, F.; Chen, Y.; Yang, H.; Saeedi, Ali; Hossain, Mofazzal (2019)© 2018 Elsevier B.V. Wettability of an oil/brine/sandstone system is an important petro-physical parameter, governing subsurface multi-phase flow and residual oil saturations. While how edge-charged clays (e.g., kaolinite) ...
Role of Basal-Charged Clays in Low Salinity Effect in Sandstone Reservoirs: Adhesion Force on Muscovite using Atomic Force MicroscopeAl Maskari, N.; Xie, Q.; Saeedi, Ali (2019)Low salinity water flooding appears to be an important means to improved oil recovery in sandstone reservoirs. Wettability alteration has been identified as the main effect behind low salinity water flooding due to the ...
Role of ion exchange, surface complexation, and albite dissolution in low salinity water flooding in sandstoneChen, Y.; Xie, Sam; Saeedi, Ali (2019)Wettability alteration appears to be an important mechanism for low salinity water flooding, but two major challenges in predicting the low salinity effect are (1) to understand the contribution of ion exchange, surface ...