Optimizing Ion-Tuned
Diluted Formation Water for Sustainable Enhanced Oil Recovery in Sandstone Reservoir
Barman Joyshree, Bordoloi Tanaya, Saikia Jyoti Bhaskar and Talukdar Prasenjit
Res. J. Chem. Environ.; Vol. 29(8); 36-43;
doi: https://doi.org/10.25303/298rjce036043; (2025)
Abstract
Ion-tuned diluted formation water (DFW) optimization offers a sustainable alternative
to conventional low-salinity water (LSW) flooding for enhanced oil recovery (EOR)
in sandstone reservoirs. This study investigates the effects of DFW and LSW through
wettability alteration (WA), zeta potential (ZP), conductivity measurements, X-ray
diffraction (XRD), Scanning electron microscopy (SEM) and coreflooding experiments.
DFW samples were prepared by diluting distilled water (DW) in ratios of 1:1 to 1:9,
with DFW-7 exhibiting properties closest to LSW and selected for further comparison.
Experimental results demonstrate that ion-tuned dilution effectively modifies rock-fluid
interactions, reducing clay swelling and enhancing oil displacement.
ZP measurements indicated increased electrostatic stability, while conductivity
trends confirmed reduced salinity, minimizing formation damage. XRD and SEM analyses
showed that DFW-7 mitigates pore-scale mineral precipitation and clay swelling,
preserving permeability better than LSW. Coreflooding confirmed DFW-7 recovered
56.41% IOIP while maintaining reservoir integrity whereas LSW achieved higher initial
recovery (61.44% IOIP) but led to greater permeability loss due to fines migration.
LSW improves wettability alteration and recovery efficiency, it risks long-term
reservoir damage. DFW-7 offers an optimal balance between formation stability and
EOR efficiency, making it a more sustainable and field-applicable technique for
sandstone reservoirs.
