Caracterización petrográfica y petrofísica de la roca encajante de la Cueva del Rull (Vall d'Ebo, Alicante)

La Cueva del Rull se encuentra en el sector nororiental de la Cordillera Bética, en el denominado Prebético Externo de Alicante (Azema 1977). Regionalmente, la zona de estudio está dominada por la dinámica compresiva de los materiales calizos existentes (Cretácico Superior) afectados, desde el Mioceno Medio y durante el Mioceno Superior, por diversos movimientos tectónicos a partir de los cuales se origina la Depresión de la Vall d'Ebo. Esta fosa tectónica, cuyos bordes norte y sur quedan delimitados por fallas normales con dirección aproximada E-O, está rellena por materiales rudíticos de edad Mioceno Superior, predominantemente conglomeráticos, de espesor variable (decenas a más de 100 metros), localmente plegados y depositados sobre margas de facies “tap” (margas mal estratificadas de carácter arcillo-limoso, desagregadas y de color blanquecino en superficie, cuya edad se atribuye al Mioceno Medio).Este trabajo ha sido financiado por el proyecto CGL2011-25162 del Ministerio de Economía y Competitividad. C. Pla cuenta con una beca predoctoral del MEC correspondiente a dicho Proyecto

Experimental relationship between water permeability and capillarity imbibition in porous rocks

The movement of fluid through porous systems in rocks has been widely studied in several fields of research such as ground water, petroleum engineering, engineering geology, soil physics and building materials.This research was financed by the Spanish Ministry of Science and Innovation (CGL2011-25162). A pre-doctoral research fellowship was awarded to C. Pla for this project

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]

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

Predicting water permeability in sedimentary rocks from capillary imbibition and pore structure

In this paper, absolute water permeability is estimated from capillary imbibition and pore structure for 15 sedimentary rock types. They present a wide range of petrographic characteristics that provide degrees of connectivity, porosities, pore size distributions, water absorption coefficients by capillarity and water permeabilities. A statistical analysis shows strong correlations among the petrophysical parameters of the studied rocks. Several fundamental properties are fitted into different linear and multiple expressions where water permeability is expressed as a generalized function of the properties. Some practical aspects of these correlations are highlighted in order to use capillary imbibition tests to estimate permeability. The permeability–porosity relation is discussed in the context of the influence of pore connectivity and wettability. As a consequence, we propose a generalized model for permeability that includes information about water fluid rate (water absorption coefficient by capillarity), water properties (density and viscosity), wetting (interfacial tension and contact angle) and pore structure (pore radius and porosity). Its application is examined in terms of the type of pores that contribute to water transport and wettability. The results indicate that the threshold pore radius, in which water percolates through rock, achieves the best description of the pore system. The proposed equation is compared against Carman–Kozeny's and Katz–Thompson's equations. The proposed equation achieves very accurate predictions of the water permeability in the range of 0.01 to 1000 mD.This study was financed by the Spanish Ministry of Science and Innovation CGL2011-25162. A pre-doctoral research fellowship was awarded to C. Pla for this project