Role of Brine Composition and Water-Soluble Components of Crude Oil on the Wettability Alteration of a Carbonate Surface

Abstract

In this study, the effects of amphiphilic water-soluble components of crude oil and ionic composition of water were investigated on the wettability alteration of a carbonate surface. Four different types of saltwater, which are made up of NaCl, MgCl2, CaCl2, and Na2SO4, with 0.5 M ionic strength, besides distilled water, were contacted with crude oil to be saturated with water-soluble components. The post-contact (after contact with crude oil) water properties were characterized by Fourier transform infrared spectroscopy, total organic carbon, and pH analyses. The results showed that some polar compounds of crude oil with basic and mostly acidic functional groups were transferred to saltwater and distilled water. Afterward, the oil-wet carbonate surface was soaked in both freshwater (not contacted with crude oil) and post-contact water, and their effects on the wettability of the surface were investigated through contact angle and scanning electron microscopy experiments. The results of the contact angle indicated that generally, soaking of the oil-wet carbonate surface in both freshwater and post-contact water altered the wettability of the carbonate surface toward more water-wetness. However, the presence of water-soluble components in post-contact water (except for Na2SO4 saltwater), significantly reduced its wettability alteration efficiency in comparison to freshwater. Similarly, when water contains the Ca2+ ion, the calcite surface could not be dissolved in the aqueous phase, and accordingly, wettability alteration would be seriously retarded in both freshwater and post-contact water. Moreover, several mechanisms may jointly contribute in wettability alteration of the carbonate surface, which include organic–ionic layer dissolution into the aqueous phase, dissolution of the calcite surface alongside its adsorbed amphiphilic compounds, expansion of the electrical double layer, pairing of the Mg2+ ion with surface-absorbed compounds, Mg2+ substitution for Ca2+ on the calcite surface, and interaction of cationic components with absorbed acidic compounds.

Formation and Stability of Heterogeneous Organo–Ionic Surface Layers on Geological Carbonates

“…A small but nontrivial fraction of CRO is water-soluble, dissolving into complex brines (formation and high-salinity injection water), ,, simple brines and distilled water. − Some of these water-soluble oil components can bind to mineral surfaces, altering mineral wettability. ,,, Thus, oil–brine phase transfer reactions appear crucial in setting initial reservoir conditions and subsequent oil recovery process. Yet computational and laboratory studies tend to utilize purely inorganic compositions of formation water and injection brines.…”

Implications of anionic and natural surfactants to measure wettability alteration in EOR processes

“…These methods have been used for decreasing the interfacial tension, raising the brine viscosity as a mobility control, and increasing sweep efficiency in tertiary recovery (Taber et al, 1997;Shandrygin and Lutfullin, 2008;Rai et al, 2015;Davarpanah, 2018;Mejia et al, 2019). The wettability of an oil reservoir affects the fluids flow displacement and its location in the porous media during the production, and it is a crucial parameter in oil recovery processes (Anderson, 1986;Zhang et al, 2012;Bahaloo Horeh et al, 2019;Emadi et al, 2019;Mofrad and Saeedi Dehaghani, 2020;. The reservoir rock mineralogy has a significant impact in the interaction mechanism between externally added surfactants and reservoir minerals and their influences on solid-liquid interfacial properties such as wettability and surface charge (Somasundaran and Zhang, 2006;Tu and Sheng, 2020;Chávez-Miyauchi et al, 2016).…”

Synergistic effect of salt ions and water‐soluble amphiphilic compounds of acidic crude oil on surface and interfacial tension

“…These salts were chosen based on their presence in both seawater and formation brine, and the vital role of these salts in enhanced oil recovery (EOR) process. [ 53,55–57 ] The salt waters were prepared through dissolving a certain amount of the pure salt (over 99%, Merck Company) in distilled water.…”

“…Recently, we studied the effect of soluble components on rock‐fluid interaction and wettability alteration. [ 53 ] The presence of water‐soluble components can effectively influence wettability of the rock in the low salinity water (LSW). Previously, Ghorbanizadeh et al presented the effects of ionic modification of the injected water and amphiphilic compounds on fluid‐fluid interaction.…”