3D Modelling of Fault Bounded Pressure Compartments in the North Viking Graben

The work presented in this paper involves modelling of the overpressure distribution in Jurassic reservoir and carrier rocks in the North Viking Graben. The main concept used in this study is that faults may form low-permeability barriers to fluid flow in compacting basins, and may thus influence overpressure distribution. The mapped faults in the study area are linked together so that they divide the area into 225 compartments. A model based on Darcy's law and information about offset and burial depth describes the flow conditions across the faults and between the compartments. This model describes a regional fault permeability architecture. A commercial reservoir simulator is used to calculate the fluid flow and the pressure development in all the compartments. The model was calibrated to pressures measured in 16 released exploration wells. The best match to these wells was obtained with a mean deviation of 9.5 bars and a standard deviation of 18.5 bars between the observed and predicted overpressures for the Brent Group. The results from this pressure modelling can be used to simulate secondary migration of oil and gas.