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I recently had a lecture on diffusion as a method for fluid or heat flow through a medium. As I am interested in petroleum geology I was thinking if this would also be applied to oil reservoirs. I imaging that oil or gas flows to the point with least pressure and over time will try to achieve an even pressure throughout the connected reservoir. Can anybody explain to me if reservoir simulation software uses these diffusion laws to model gas-oil saturation and flow? I read that finite difference models are often used, but I can't find out if these use diffusion laws?

merci!

Dion

Hi - Permedia MPath (http://www.permedia.ca) allows for modelling the effects of diffusion, however in terms of large-scale migration its usually not the dominant method of mass transport. It does come into effect for accumulations that have long residence times as well as in-reservoir mixing processes.

Hope that helps.

Thank you for this! So what I understand diffusion is generally not the method for modeling fluid flow in reservoirs. I am reading deeper into finite element models but they basically are models that use a mesh (that can have different sizes) so that spatial differences (and changes) can be modeled; am i right?

But can you explain how flow is calculated between cells.
I imagine each cell (A) just 'looks' at it's neighbours and if there is a lower saturation, pressure or higher OWC contact there the oil will flow there (cell B). As this process is iterated the saturation, pressure or OWC will also change in cell A and thereby start effecting cell C for instance. Is this clear and is it how it works?

thanks!