Fig. 10

Verification of directional permeability caused by anisotropy of rock samples. a The measurements are distributed along each spatial dimension of the cylindrical plug to generate vertical (\(k{\text{v}}\)) and horizontal (\(k{\text{h}}\)) permeability information. Horizontal permeability generally shows a higher variance due to vertical variations in deposition. Sample C contains abundant vugs along the cylinder, which significantly increase the horizontal permeability, while the vertical permeability of sample F is reduced due to stylobedding. b Permeability anisotropy for all samples measured with the air-driven permeameter, which often show a higher permeability in the horizontal direction