Wettability Alteration and Adsorption of Mixed Nonionic and Anionic Surfactants on Carbonates

Abstract

Mixed-surfactant systems consisting of secondary alcohol ethoxylates and anionic sulfonates are evaluated as wettability alteration agents for enhanced oil recovery. The cloud points of the nonionic surfactants are raised by the addition of the sulfonates. The oil/water interfacial tension and contact angles of oil on initially oil-wet calcite are reported at different temperatures and surfactant compositions. Adsorption experiments are performed for select mixed systems at high temperatures. The extent of the increase in the cloud point, changes in the contact angle, and adsorption are influenced by co-surfactants, surfactant concentrations, and temperatures. Mixed surfactant systems were identified which modified the oil-wet surface to a water-wet surface with final contact angles as low as 70°. Mixed surfactants exhibit a linear trend in adsorption and wettability alteration with the thermodynamic descriptor of cloud point temperature difference, which has been used previously for single surfactants. These findings enable the design of surfactant formulations for wettability alteration in high temperature, high salinity reservoirs.

Rock–Fluid Interactions of Alkyl Ether Carboxylate Surfactants with Carbonates: Wettability Alteration, ζ-Potential, and Adsorption

“…Deng et al 77 reported that carbonate rock (Indiana limestone was used in their work) became oil-wet after 0.5 days of contact with oil at 90 °C due to its strong tendency to oil wetness. Das et al 34 soaked Iceland Spar plates in oil at 120 °C for 2−3 days. Sharma et al 4 aged calcite mineral plates in oil 78 performed a statistical analysis of core samples with different mineral compositions soaked in various oils.…”

“…SAE surfactants can be used in mixtures with anionic sulfonates to increase the cloud point and expand the range of reservoir conditions where they can be applied. 34 Souayeh et al developed a cost-effective wettability alteration (WA) process based on a combination of a polyethoxylated nonionic surfactant with low-salinity brine. 35 Contact angle measurements showed that the wettability changed from the oil-wet to the water-wet state.…”

Surface Energy and Wetting Behavior of Dolomite in the Presence of Carboxylic Acid-Based Deep Eutectic Solvents

“…Analysis and estimation of the wetting behavior of oil reservoir rocks are imperative for enhanced oil recovery (EOR) operations, as wettability defines fluid distribution inside pore spaces . Previous studies have shown that certain chemicals (surfactants and nanoparticles, as examples) can alter the wettability of oil-wet rock samples toward a water-wet state, − where salinity, temperature, crude oil type, and mineral type are considered as dominant parameters . Among various types of chemicals, surfactants (anionic, cationic, and nonionic) have long been recognized as wettability alteration agents. ,,,, However, despite tangible advancements in the design and preparation of surfactants, environmental concerns, availability, cost of preparation, and adsorption issues of these chemicals have led scientists to explore new alternatives .…”

“…3 Among various types of chemicals, surfactants (anionic, cationic, and nonionic) have long been recognized as wettability alteration agents. 3,6,7,11,12 However, despite tangible advancements in the design and preparation of surfactants, environmental concerns, availability, cost of preparation, and adsorption issues of these chemicals have led scientists to explore new alternatives. 13 In this respect, deep eutectic solvents (DESs), a new class of green chemicals, have recently been introduced as an alternative to surfactants.…”

“…Previous studies have shown that certain chemicals (surfactants and nanoparticles, as examples) can alter the wettability of oil-wet rock samples toward a water-wet state, − where salinity, temperature, crude oil type, and mineral type are considered as dominant parameters . Among various types of chemicals, surfactants (anionic, cationic, and nonionic) have long been recognized as wettability alteration agents. ,,,, However, despite tangible advancements in the design and preparation of surfactants, environmental concerns, availability, cost of preparation, and adsorption issues of these chemicals have led scientists to explore new alternatives . In this respect, deep eutectic solvents (DESs), a new class of green chemicals, have recently been introduced as an alternative to surfactants. − …”