The value of fault analysis for field development planning

Faults play an important role in reservoir compartmentalization and can have a significant impact on recoverable volumes. A recent petroleum discovery in the Norwegian offshore sector, with an Upper Jurassic reservoir, is currently in the development planning phase. The reservoir is divided into several compartments by syn-depositional faults that have not been reactivated and do not offset the petroleum-bearing sandstones completely. A comprehensive fault analysis has been conducted from core to seismic scale to assess the likely influence of faults on the production performance and recoverable volumes. The permeability of the small-scale faults from the core were analyzed at high confining pressures using formation compatible brines. These permeability measurements provide important calibration points for the fault property assessment, which was used to calculate transmissibility multipliers (TM) that were incorporated into the dynamic reservoir simulation model to account for the impact of faults on fluid flow. Dynamic simulation results reveal a range of more than 20% for recoverable volumes depending on the fault property case applied and for a base case producer/injector well pattern. The fault properties are one of the key parameters that influence the range of cumulative recoverable oil volumes and the recovery efficiency.