|Funding for:||UK Students, EU Students|
|Placed On:||28th May 2020|
|Closes:||31st August 2020|
Supervisor: Dr A. Vorobev
Mineral hydrocarbons are likely to remain a primary resource for power and chemical industries, as hydrocarbon derivatives are fuels, plastics, resins, fabrics, lubricants, solvents, detergents, precursor chemicals, and a great number of other highly useful everyday products, inseparable from today’s world. The UK energy and refinery industries are highly dependent on import of mineral hydrocarbons, and this dependency worsens every year owing to abandonment of North Sea oil fields. Abandoned oil fields are not fully ‘depleted’, they still possess up to 40-60% of initial reserves that however remain unrecoverable with the use of current techniques.
Based on everyday observations, one knows that a sponge taken out of water remains water-saturated, with water entrapped by capillary forces. Capillary trapping is the main mechanism that prevents the recovery of residual oils from mature oil fields.
A large number of experimental and field studies confirm that vibrational stimulation of a porous reservoir improves the percolation of fluids. Although a detailed understanding of the physical mechanisms that are responsible for this effect remain obscure, and hence its quantitative description remains unavailable. We aim to develop a new comprehensive model that will explain how vibrations break capillary trapping.
It is known that small-amplitude but high-frequency vibrations are able to change the conditions of mechanical equilibrium. The best-known example is the Kapitza’s pendulum, when bob is stabilized in an inverted position, above suspension point, by vibrating the suspension. Similarly, high-frequency vibrations of a two-phase fluid system may retain a heavier liquid on top of a lighter liquid.
We aim to show that shaking of a porous matrix can alter the mechanical equilibria of droplets entrapped in a matrix, either strengthening trapping of the droplets, or mobilising the droplets, separating the liquid phases within a porous medium.
This hypothesis will be validated by examining the stability and dynamics of liquids within a single capillary and within a network of capillaries (a representative element of the porous medium) that are subjected to mechanical vibrations. The evolution of two liquids will be numerically modelled using a recently-developed continuum (phase-field) approach for the time-averaged description of the effects of high-frequency vibrations on the behaviour of heterogeneous (with interfaces) binary mixtures. A CUDA-enabled numerical code will be developed and employed.
Handling of the vibrational effects that will be achieved by this project will provide a breakthrough technique for dynamic control of capillary trapping. This will be a new interesting tool for a more secure storage of gases and liquids within porous materials (required for CO2 sequestration), or for unlocking entrapped phases, separating liquids within a porous medium (needed for enhanced oil recovery or for efficient cleaning of porous materials).
A good undergraduate degree (at least a UK 2:1 honours degree).
Closing date: applications should be received no later than 31 August 2020.
Funding: full tuition fees for EU/UK students plus for UK students, a stipend of £15,285 tax-free per annum for up to 3.5 years.
How To Apply
Apply online, select the academic session 2020-21 “PhD Eng & Env (Full time)” as the programme. Enter Dr A. Vorobev under the proposed supervisor.
Applications should include:
Two reference letters
Degree Transcripts to date
For further information please contact: email@example.com
Type / Role: