Surfactants for water /CO2/Hydrocarbon emulsions for combined CO2 storage and utilization

The goal of the project is to investigate and understand the key mechanisms of surfactant adsorption at liquid-liquid interfaces, which would provide essential informations for  developing efficient combined Enhanced Oil Recovery (EOR) / CO2 storage technology.

Several surfactants have successfully been applied to create stable emulsions of water and CO2. In addition, it seems that some of these have an even better affinity for aromatic hydrocarbons. In this case the injection of a water/CO2 emulsion leads to the creation of a new water/hydrocarbon emulsion. The efficiency of the process depends on the rate of CO2 release from the water: for low release rates CO2 end up as bubbles inside the continuous water phase. On the opposite side, the CO2 may release rapidly and form plumes acting similarly as the alternating water/CO2 flooding, which is widely known as a more efficient EOR technique than flooding only water or CO2 alone. The kinetics of the transition from a water/CO2 emulsion to the water/hydrocarbon one can be controlled by the design of the emulsifier, which is one of the goals of this project.

Fig 1: Pattern formation during phase separation in a ternary (left) and quaternary (right) liquid.

Technically more precisely, first we will analyze phase-field type continuum models of surfactant assisted phase separation to identify the key mechanisms of adsorption kinetics, then calibrate them for the water/CO2 and water/hydrocarbon systems by using miscroscopic interfacial properties emerging from experiments and atomistic simulations. Next, we plan to develop a multiphase description in order to model the full, water/CO2/hydrocarbon three-phase flow. It would open the possibility to define the range of desired material parameters establishing proper CO2 release rate during the formation of the new hydrocarbon/water phase.

Through the use of this state-of-the-art theoretical tool the main goal of the project is contribute substantially to the development of next generation of emulsifiers for CO2/water/hydrocarbon/emulsifier system. Secondary goals are the development of a general multi-scale modeling tool for understanding the mechanisms involved, estimating characteristic thermodynamic and kinetic parameters and provide a basis for development of qualified simplified correlations for use in reservoir modeling of the same systems.

Fig 2: Simulation of emulsion formation in the water/heptane/asphaltene system.

Publications:
[1] G. I. Tóth, B. Kvamme, "Analysis of Ginzburg-Landau-type models of surfactant-assisted liquid phase separation" Phys. Rev. E 91, 032404 (2015).

[2] G. I. Tóth, B. Kvamme, "Phase field modelling of spinodal decomposition in the oil/water/asphaltene system", Phys. Chem. Chem.

Phys. 17, 20259 (2015).

[3] G. I. Tóth, T. Pusztai, L. Gránásy, "Consistent multiphase-field theory for interface driven multidomain dynamics", Phys. Rev. B 92,

184105 (2015).

[4] G. I. Tóth, M. Zarifi, B. Kvamme, "Phase-field theory of multicomponent incompressible Cahn-Hilliard liquids", Phys. Rev. E 93,

013126 (2016).

[5] G. I. Tóth, "Phase-field modeling of isothermal quasi-incompressible multicomponent liquids", Phys. Rev. E 033114 (2016).

[6] G.I. Tóth, J. Selvåg and B. Kvamme, "A phenomenological continuum theory of asphaltene stabilized oil/water emulsions", submitted to Energy & Fuels (2016).