Impact of Fault Rock Properties and Sub-seismic Scale Faults on Fluid Flow in Penguins C Field, North Sea

Fault transmissibility derived from lateral connectivity between compartments and changes with depletion was recognised as key subsurface uncertainty in the field. Therefore, structural logging and analyses (fault tip extensions), microstructural and petrophysical property analyses were carried out on cores obtained from 2 wells in the field, in order to assess their impacts on hydrocarbon recovery. Results of the sub-seismic fault characterisation and structural analyses were integrated into a structural modelling and dynamic fault seal project to aid in understanding current production behaviour, and predict possible infill locations. The modelling effort involved using the Petrel 3D Static reservoir models, underpinned by measured fault properties from Rock Deformation Research (RDR, 2000) on Brent and Triassic reservoirs. The result of this work showed that majority of the faults will act as strong baffles in production timescale, however, low, base and high fault permeability and thickness parameters were selected for dynamic simulations. Dynamic simulation sensitivities carried out with the range of potential fault properties bracketed the historical production behaviour observed in the field. Using the historically observed data (production, pressures) the uncertainty ranges for the fault properties were constrained and a suite of history matched models created to allow optimisation of potential infill wells.