Response to ENGEO7253 Discussion of: “Predicting water permeability in sedimentary rocks from capillary imbibition and pore structure” by D. Benavente et al., Engineering Geology (2015) [doi: 10.1016/j.enggeo.2015.06.003]

Abstract

The authors would like to express their thanks to C. Hall and A. Hamilton for their interest, clarifications and suggestions about our paper, mainly in the analysis of wettability effects on capillary imbibition. They theoretically supported the permeability, porosity and capillary imbibition relations and elegantly demonstrated some of the empirical equations obtained in our paper. They also proposed using low surface-tension liquids to avoid wettability effects on permeability estimations. This discussion is an excellent opportunity to present additional comments and results and to clarify certain aspects of our paper that may not have been clear enough. Thus, we here highlight that our scaling relations assume that rocks present a homogenous porous medium and the saturation state of the wetted zone in capillary imbibition test is the same as the saturation state in the saturated permeability test. As Hall and Hamilton's Discussion points out, this is not generally true since the mean liquid content of the wetted zone in imbibition is below saturation as a result of air-trapping.