Immiscible Contaminants in Natural Porous Media
SEIT AcademicsDr Robert Niven
Postgraduate StudentsMs Yasmin A. M. A. Abdelraouf
Control of the geometric form and mobility of an immiscible fluid phase, such as air or hydrocarbon liquids, in water-saturated natural porous media (soil and rock materials) has emerged as one of the most demanding engineering challenges of the 21st century. When subject to fluid flow, such immiscible fluids tend to fragment to form discrete gas bubbles or fluid droplets – commonly referred to as ganglia – which remain trapped in the porous medium due to the strong forces induced by surface or interfacial tension. Such droplets are then effectively immobilised. It has been estimated that some 20-30% of known petroleum reservoirs have been rendered unrecoverable by this mechanism, of critical importance in light of concerns over limitations to world oil supply (“peak oil”). In addition, such entrapment substantially increases the cost and difficulty of remediation of immiscible contaminants, such as hydrocarbons and solvents, from contaminated sites. Furthermore, efforts to redress global warming by the geosequestration of CO2, involving the injection of CO2 into deep geological formations, could be significantly impaired by this mechanism. For these reasons, a long-standing body of research has been conducted in SEIT on the behaviour of immiscible fluids in natural porous media.
In 2011 the following projects were conducted as part of this research theme: