Different Methods of Predicting Permeability in Shale

Permeability is often very difficult to measure or predict in shale lithology. In this work we are determining shale permeability from consolidation tests data using Wissa et al., (1971) approach and comparing the results with predicted permeability from Kozeny’s model. Core and cuttings materials were obtained from Fjerritslev shale Formation in Juassic interval of Stenlille and Vedsted on-shore wells of Danish basin.

The calculated permeability from specific surface and porosity vary from 0.09 to 48.53 μD while that calculated from consolidation tests data vary from 1000 μD at a low vertical effective stress to 9 μD at high vertical effective stress of 100 MPa. The indirect permeability calculated from consolidation tests falls in the same magnitude at higher vertical effective stress, above 40 MPa, as that of the Kozeny model for shale samples with high non-clay content ≥ 70% but are higher by two to five orders of magnitudes at lower vertical effective stress below 40 MPa as the content of clay minerals increases causing heterogeneity in shale material.

Indirect permeability from consolidation can give maximum and minimum values of shale permeability needed in simulating fluid flow in shale useful in assessing their integrity for CO2 storage, gas shale exploitation and other engineering applications.