Abstract: A fault seal analysis system with a data input which receives data pertaining to one or more physical parameters of a rock stratigraphy at or near a fault and means for analysing the data by applying one or more algorithm to create a model of the geometry and physical properties of the rock at or near the fault, the analysis means further comprising a user input which allows a user to vary input parameters of the one or more algorithms and creating one or more data volumes or models of the geometric and physical parameters. The analysed data is represented on a fault plane property viewer having at least one fault property diagram of a fault and a software module adapted to interrogate the data volume to map data from the data volume onto the diagram to show the sealing properties of the fault.