The objective is to develop models and other tools that can be used to help understand, predict and prevent a broad class of flow assurance problems.
Our overall goal is to develop generic methods to describe complex fluid systems in tools that can be incorporated into scaleable and robust multiphase flow assurance models needed by the petroleum industry for developing new production solutions for oil fields with complex well fluids.
Lattice Boltzmann simulation of a two-phase flow.
Multiphase flow simulation
Droplets of oil or water embedded in water or oil is a common situation. We can study the properties of such systems using two-fluid simulations with or without surfactant. How droplets break up to smaller ones in shear flow, and how the droplets are generated from large scale interfaces in initially layered flow, are topics we study. The stabiltiy and rheology for oil-in-water or water-in-oil emulsions may also be studied.
The classes of fluids to be addressed in the FACE Centre are suspensions, emulsions and heavy crudes. Collectively, these are referred to as “complex fluids”. The challenge of the FACE Centre is to address Flow Assurance in Multiphase Systems, so that the models and other tools developed in this project must be capable of describing multiphase flows in which one or more of the phases is a complex fluid.
2D Lattice Boltzmann simulation
In the simulation example shown, we demostrate the breakup of a single droplet into smaller ones. The right wall is moving upwards and the left downwards. Fluid is injected asymetrically
The large initial droplet is stretched in the shear to form a filamnet. This is unstable due to capillary forces and generate smaller drops, that may later coalesce. Such simulation can be extended to 3D where the instability is even more efficient.
2D simulation of emulsion stability.
The upper movie shows that coalescence stops at a certain characteristic droplet size, when there is surfactant in the system. Equilibrium is reached when the energy in the system is at a minimum, determined by the balance between interfacial energy (surface tension times total surface area, which is large for a large number of small droplets) and the chemical potential energy of the surfactant. The lower movie shows the same case, but without surfactant. Here one would eventually have one single droplet, providing the minimum surface energy.
Both cases are in zero g, and with no walls (periodic boundaries). These cases can also be studied with moving walls and with gravity, to understand more of the rheological properties of oil/water emulsions for complex fluids containing surfactants.