Understanding surface wettability in EOR processes

Water injection techniques based on enhanced oil recovery (EOR) can significantly increase reservoir yields. Typically, the yields of oil reservoirs revolve around 20 to 40% in contrast to the yields observed in gas reservoirs of the order of 80 to 90%. In the pore scale, the performance of these techniques depends, among other factors, on the physical-chemical characteristics of the water-oil-rock interfaces, in particular on the interfacial tension between the phases. The main reason is related to the direct relationship between the interfacial tension and the capillary forces of the porous medium (rocks) where a large part of the oil is retained due to the residual saturation of the rock. The interfacial tension arises at the interface between two fluids, related to the interaction between oil molecules and water in the emulsions present in the reservoir, keeping the interfaces in contact with certain characteristics.

In this sense, this project aims, using state-of-the-art instruments from the Laboratory of Surfaces and Interfaces to investigate mineral-water-oil interfaces at the atomic and molecular scale, the mechanisms of adsorption, interaction and reversal of oleophilicity and hydrophilicity of water-oil mixtures at different temperatures, salinity and pH conditions on well-defined crystalline planes of minerals of interest (eg calcite, dolomite, aragonite, siderite, quartz). The surface characterization techniques allows us to verify how molecules present in the mixtures interact, modify and adsorb on the surface of the minerals and the changes in the physical and chemical characteristics of the interfaces as a function of thermodynamic parameters (pH, temperature and ionic concentrations) and their effect on mineral wettability.