IMPACT OF SO42−, CA2+, AND MG2+ IONS IN CASPIAN SEA ION-ENGINEERED WATER ON THE RATE OF WETTABILITY ALTERATION IN CARBONATES
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Date
2020-09-20
Authors
Bazhanova, Meruyet
Pourafshary, Peyman
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Petroleum Exploration and Production Technology
Abstract
Tuning the salinity and concentration of potential-determining ions, such as Mg2+, Ca2+, and SO4
2−, could alter the wettability
toward a more water-wet state. The rate of alteration in carbonate rock wettability is a critical parameter to design the duration
of the ion-engineered water fooding. Characteristic experiments, such as dynamic contact angle and pH measurements, ion
chromatography, and spontaneous imbibition, are applied to study the rate of wettability alteration using diferent samples
of ion-engineered water. Our study shows that the Caspian Sea water (CSW) with a salinity of 15,000 ppm is an efcient
displacing fuid as it can initiate the multi-ion exchange (MIE) mechanism and alter the wettability from 86° to 35° within
2 d. The adjustment of salinity and active ion concentration makes the MIE mechanism much faster. For example, with fve
times diluted CSW, the same change in wettability is only achieved only within 9 h. Spiking the concentration of Ca2+ and
SO4
2− ions is used to further shift the contact angle to 22° within 9 h. Spontaneous imbibition tests demonstrate that the rate
of oil production doubles as a result of the ion-engineered brine due to the faster MIE process. The results obtained from this
research work suggest that even a short period of interaction with optimized engineered water can afect the brine, oil, and
carbonates interactions and change the reservoir rock initial wettability from neutral to strongly water-wet state. This allows
to efciently design engineered water fooding based on CSW in the feld scale and make such projects more proftable.
Description
Keywords
Type of access: Open Access, Ion-engineered water, Low salinity water, Caspian sea, Wettability, Active ions
Citation
Bazhanova, M., & Pourafshary, P. (2020). Impact of SO42−, Ca2+, and Mg2+ ions in Caspian Sea ion-engineered water on the rate of wettability alteration in carbonates. Journal of Petroleum Exploration and Production Technology, 10(8), 3281–3293. https://doi.org/10.1007/s13202-020-01006-z