Many academic computational studies are conducted on homogeneous, atomically flat idealized systems. However, most practical systems show surfaces that are not chemically homogeneous, nor atomically flat. Can we extrapolate our understanding developed on idealized substrates to imperfect, real ones? How can we adapt the simulation strategies to take into consideration the main aspects of realistic systems? What are such ‘main’ aspects? In this presentation some examples from our recent research will be presented, together with possible applications in the energy sector.

We will start from atomistic molecular dynamics simulations conducted for identifying possible mechanisms by which hydrocarbons can be dislocated from sub-surface formations. When conducted on idealized systems such simulations can provide information that is often qualitatively, and sometimes quantitatively in agreement with experiments. Although these results are encouraging, practical applications require quantifying the effect of heterogeneous properties on macroscopic observables. For example, fluid transport through shale rocks is difficult to predict because the pores are narrow, the pore connectivity is low, and the rocks are very heterogeneous. In these conditions, it is known that phenomenological equations such as the Darcy’s law, as well as analytical models such as the effective medium theory can fail. We have applied a stochastic approach, based on the kinetic Monte Carlo algorithm, which has proven valuable both in up-scaling the atomistic molecular dynamics simulation results and in attempting to quantify rock permeability based on materials characterization.

The second example is related to the flow assurance problem: clathrate hydrates can form in oil & gas pipelines, blocking and sometimes rupturing the pipes. We studied molecularly thin films of surfactants adsorbed on methane hydrates. In some cases, we observed a ‘frozen interface’. Interestingly, the surfactants that showed such structure are effective in preventing the formation of hydrate plugs. Did we identify a property useful to discover new surfactants for applications?

The third example is perhaps further from a direct application, but it concerns emulsions, which are present in many cosmetics, sometimes they are a nuisance, and other times we would like them to be stable for long time. When solid particles are used to stabilize emulsions, they are known as Pickering emulsions. We studied how Janus vs. homogeneous nanoparticles might affect the stability of Pickering emulsions. We also investigated how a droplet, covered by nanoparticles, changes its shape upon shrinking. Its shape can be modified by controlling the rate by which the droplet is shrank, and also by using Janus vs. homogeneous particles. Are these results just nice pictures, or could they help trigger innovations, e.g., in materials synthesis?

Back to event list

By: Sean Paul Ogilvie
Last updated: Friday, 6 April 2018