Fredagskollokvium: A talk about geophysics. Some animated examples of fluids - rocks interactions

First I will introduce briefly some aspects of geosciences. This talk
will then focus on interactions between fluids and rocks. Fluid
circulations have a strong influence on thermal, mechanical and
chemical processes occurring in the rock.  These processes depends on
the geometry of the interface between the solid and the fluid. I will
show modelling of the fluid circulation in a rock, using complex geometrical data acquired by computer
tomography. Fluid channelling occurs in fractures due to topography
variations. Hydro-thermal interactions will then be shown.  Modelling
and experimental measurements of the rock and fluid temperature fields
will be shown in the context of geothermal energy, when cold fluid is
injected into a fractured hot bedrock. This work is done in fractures
(centimetre to half a meter long).  I will then present experiments
that illustrates that, vice versa, the geometry of the fluid-rock
interface evolves itself in function of the chemical and mechanical
interactions between the solid and reactive fluid that
circulates. These experiments are done in chalk samples, with
microscope observations from about 50 micrometer to centimetre
scale. Chalk constitutes large and challenging oil reservoirs in
Norway. In-situ observations of structural changes in the pore space
of porous rocks during reactive flow provide valuable insights into
the pore scale mechanisms that may increase oil recovery. Notions of
wettability and relative permeability will be explained.