A Review on Wettability Alteration in Carbonate Rocks: Wettability Modifiers

Abstract

More than half of the global oil reserves are in carbonate reservoirs. Carbonate rocks, however, in most cases tend to be mixed-wet or oil-wet. Wettability alteration of carbonate reservoir rock has been proven to increase oil recovery significantly. Several chemicals have shown their effect on wettability; however, selection of an appropriate wettability modifier should be made on the basis of the underlying mechanisms and their behavior at reservoir conditions. This review discusses techniques that can help in assessing wettability alteration or reflect on the underlying mechanism and describes several categories of wettability modifiers focusing on their structure−property relationship and factors affecting their performance at reservoir conditions. Surfactants, nanoparticles, salts, and alkalis are four major categories of wettability modifiers that are discussed in this review. Among surfactants, gemini surfactants have great potential and could be a major focus of future research in this area. Nanoparticles are relatively novel materials for wettability alteration with the capability to reduce contact angle significantly at low cost. This review also identifies the current and future challenges related to the performance of various wettability modifiers at high-temperature and high-salinity conditions.

Wettability alteration of oil‐wet carbonate rocks by chitosan derivatives for application in enhanced oil recovery

“…AFM is a convenient technique for showing the changes in sample surfaces. It is commonly used to help reflect wettability alteration mechanisms 44 . Al Nassari et al studied by AFM the effect of irreversibly adsorbed nanoparticles on the surface roughness 4,45 .…”

“…[59][60][61] Although the literature shows that low-salinity systems are capable of decreasing the residual oil content, the flooding with just brine in the solution presented a poor performance, demonstrating the need for the implementation of an EOR process. 44 The chitosan derivatives were able to satisfactorily increase the residual oil recovery factor in the porous medium experiment. TMC increased production by about 25% while TMC-C14 produced a displacement of about 16% higher.…”

“…It is commonly used to help reflect wettability alteration mechanisms. 44 Al Nassari et al studied by AFM the effect of irreversibly adsorbed nanoparticles on the surface roughness. 4,45 While Xie et al used AFM together with other techniques to understand the importance of basal-charged clays during low-salinity water flooding in sandstone reservoirs.…”

Optimal Wetting Angles in Lattice Boltzmann Simulations of Viscous Fingering

“…In particular, we aim to study the effect of the wetting angle and viscosity ratio on the viscous fingering and the saturation at breakthrough or sweep, which directly relates to the oil "Recovery Factor" in EOR. In the field of petroleum engineering, it is well accepted that the wettability is a crucial factor for EOR (Deng et al 2020), and while the relationship between wettability and recovery factors is known to be complex, there is a general consensus based on extensive research that the recovery factor increases as the invading fluid becomes more wetting (Deng et al 2020).…”

Impact of Spacer Nature and Counter Ions on Rheological Behavior of Novel Polymer-Cationic Gemini Surfactant Systems at High Temperature

“…Chemical Enhanced Oil Recovery (cEOR) methods such as a surfactant, polymer, alkali flooding, and a blend of these chemicals are found to be successful techniques to unlock more oil from carbonate reservoirs [13]. Surfactants decrease the interfacial tension (IFT) between oil and water phases, while polymers enhance the displacement efficiency by increasing the viscosity of the injected fluid, hence improving the mobility [13][14][15][16][17][18]. Recently, it has been proved that polymers having higher elasticity (storage modulus) improves the sweep efficiency.…”