A continuum representation of fracture networks. Part II: application to the Äspö Hard Rock laboratory

A method to represent fracture networks in a continuum model is evaluated by an application to the Äspö Hard Rock Laboratory (HRL). The basic approach of the method is to first generate a fracture network, based on data from field measurements and then represent the network as grid cell conductivities, using a staggered grid arrangement. It is argued that the resulting conductivity fields capture the correlation and anisotropy structures, as well as the mean conductivity, of the rock in a realistic way. The main objective is to evaluate if the suggested method can be used in an application to a real site. The objective is formulated in three questions: ‘Can the method utilize available field data?’, ‘Can the generated fields be calibrated and conditioned?’ and ‘Are realistic distributions of pressure, flow and density obtained?’. From the application to the Äspö HRL, it is concluded that the hydraulic conductivity fields, generated by the suggested method, can utilize field data and be calibrated. It is also demonstrated that realistic distributions of pressure, flow and density can be simulated.