Numerical modeling of unidirectional flow in self-affine fractures using the lubrication approximation requires averaging of the transmissivity between the nodes. Seven averaging techniques are reviewed: arithmetic averaging of transmissivity; harmonic averaging of transmissivity; two averaging techniques derived by cell-based collocation method; global reconstruction of profile by means of multiquadrics; arithmetic averaging...

The current study shows that heating a cased borehole in low-permeability shale rock can induce plastic deformation, leading to the closure of the casing annulus and decreasing annulus connectivity. The thermally induced borehole closure is interesting for the field operation of plug and abandonment (P&A), as it potentially saves operation cost and time by avoiding cutting casing and cementing. Lab experiments and numerical si...