Effect of salinity, Mg2+ and SO42- on "smart water"-induced carbonate wettability alteration in a model oil system

Jin Song; Qing Wang; Imran Shaik; Maura Puerto; Prem Bikkina; Clint Aichele; Sibani L Biswal; George J Hirasaki

doi:10.1016/j.jcis.2019.12.040

Effect of salinity, Mg²⁺ and SO₄^2- on "smart water"-induced carbonate wettability alteration in a model oil system

J Colloid Interface Sci. 2020 Mar 15:563:145-155. doi: 10.1016/j.jcis.2019.12.040. Epub 2019 Dec 12.

Authors

Jin Song¹, Qing Wang², Imran Shaik³, Maura Puerto⁴, Prem Bikkina⁵, Clint Aichele⁶, Sibani L Biswal⁷, George J Hirasaki⁸

Affiliations

¹ Rice University, 6100 Main St., MS-362, Department of Chemical and Biomolecular Engineering, Houston, TX 77005, USA. Electronic address: [email protected].
² Rice University, 6100 Main St., MS-362, Department of Chemical and Biomolecular Engineering, Houston, TX 77005, USA. Electronic address: [email protected].
³ Oklahoma State University, 420 Engineering North, School of Chemical Engineering, Stillwater, OK 74078, USA. Electronic address: [email protected].
⁴ Rice University, 6100 Main St., MS-362, Department of Chemical and Biomolecular Engineering, Houston, TX 77005, USA. Electronic address: [email protected].
⁵ Oklahoma State University, 420 Engineering North, School of Chemical Engineering, Stillwater, OK 74078, USA. Electronic address: [email protected].
⁶ Oklahoma State University, 420 Engineering North, School of Chemical Engineering, Stillwater, OK 74078, USA. Electronic address: [email protected].
⁷ Rice University, 6100 Main St., MS-362, Department of Chemical and Biomolecular Engineering, Houston, TX 77005, USA. Electronic address: [email protected].
⁸ Rice University, 6100 Main St., MS-362, Department of Chemical and Biomolecular Engineering, Houston, TX 77005, USA. Electronic address: [email protected].

PMID: 31874304
DOI: 10.1016/j.jcis.2019.12.040

Abstract

Hypothesis: We present a systematic study of the "smart water" induced wettability alteration. This process is believed to be greatly affected by the brine salinity and the presence of Mg²⁺ and SO₄^2- in the brine.

Experiments and modelling: To characterize the wettability alteration, we perform spontaneous imbibition measurement using Indiana limestone cores and a model oil with added naphthenic acid. Both single-electrolyte-based and seawater-based "smart water" are tested to investigate the effect of Mg²⁺, SO₄^2- and salinity on wettability alteration. Rock/brine and oil/brine zeta potentials are measured, and the electrostatic component of disjoining pressure is calculated to understand the role of electrostatics in the wettability alteration. The surface concentration of charged species on the limestone surface is analyzed based on a natural carbonate surface complexation model (SCM).

Findings: Both the reduction of Na⁺ and addition of SO₄^2- are found to contribute to wettability alteration. Mg²⁺ is found to be unfavorable for wettability alteration. Ca²⁺ is believed to facilitate SO₄^2- with wettability alteration based on the comparison between the single-electrolyte-based and seawater-based brines. The reduction of the Na⁺ surface complexation (>CaOH⋯Na^+0.25) in low salinity brines is believed to be a critical mechanism responsible for wettability alteration based on the SCM calculations.

Keywords: Enhanced oil recovery; Low salinity water; Smart water; Spontaneous imbibition; Wettability alteration.