Page 146 - Principles of Applied Reservoir Simulation 2E

Rock-Fluid Interaction

The previous two chapters described the data needed to model the solid
structure of the reservoir and the behavior of fluids contained within the solid
structure. Small-scale laboratory measurements of fluid flow in porous media
show that fluid behavior depends on the properties of the solid material. The
interaction between rock and fluid is modeled using a variety of physical
parameters that include relative permeability and capillary pressure [Collins,
1961; Dake, 1978; Koederitz, et al., 1989]. Laboratory measurements provide
information at the core scale (Macro Scale) and, in some cases, at the micro-
scopic scale (Micro Scale). They are the subject of the present chapter.

14.1 Porosity, Permeability, Saturation, and Darcy's Law

Porosity, permeability, and saturation can be obtained from Mega Scale
measurements such as well logs and well tests, and by direct measurement in
the laboratory. Comparing values of properties obtained using methods at two
different scales demonstrates the sensitivity of important physical parameters
to the scale at which they were measured. Ideally there will be good agreement
between the two scales; that is, well log porosity or well test permeability will
agree with corresponding values measured in the laboratory. In many cases,
however, there are disagreements. Assuming measurement error is not the source
of disagreement, differences in values show that differences in scale can impact
the measured value of the physical parameter. A well test permeability, for
example, represents an average over an area of investigation that is very large

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