Аннотация:The permeability of three shale samples is measured in laboratory
at the conditions similar to in situ (confining pressure is 41.4
MPa and pore pressure is 20.7MPa). The effective medium theory is
applied to invert parameters of shale microstructure from these measurements.
Shale is modeled as a patched medium consisting of two
types of patches related to (1) mineral matrix (2) pores and cracks. A
double-porosity model is used to describe the pore/crack geometry
of shale, which takes into account a degree of pore/crack connectivity.
The inverted parameters of shale microstructure are used to
predict the elastic wave velocities and thermal conductivity at in situ
conditions in different directions relative to the bedding plane. The
predicted values of velocities are in good correspondence with the
velocities provided by sonic logs and laboratory data. The inverted
permeability of “mineral matrix” and “fluid” patches can be used for
theoretical prediction of the permeability tensor for shale having similar
mineral composition and microstructure at the scale of laboratory measurements.