Feasibility Study of Smart Completion Application in a Complex Mature Field (Dunbar, North Sea)

Abstract

Abstract The Dunbar field is characterized by a high degree of geophysical, geological, and dynamic complexity. Current field recovery factor is 30 %, after 20 years of production. The field is compartmentalised by a number of faults, which subdivide the field into four main areas: the West Flank North, West Flank South, Frontal Central, and Frontal South, with limited to no communication between panels. Permeability degradation with depth is observed in all West Flank and Frontal panel layers, with significant impairment due to alteration of clay morphology, below paleo oil water contact, with a permeability range of only 1-10 mD. Half of Dunbar field's accumulation is located in this poor permeability region, explaining the limited recovery factor. New production technology application is necessary to help improving recovery from this low permeability region. Passive inflow-control devices (ICDs) and active inflow control valves (ICVs) provide a range of fluid-flow control options that can enhance the reservoir sweep efficiency and increase reserves. Both ICVs and ICDs are capable of equalizing the inflow or outflow into heterogeneous reservoirs. With a more evenly distributed flow profile, one can reduce water or gas coning, and solve other drawdown-related production problems, thus improving the field recovery. The objective of this study is to evaluate the interest of ICD and ICV application for the coming phase IV drilling campaign. Phase IV infill wells will encounter reservoirs with different levels of depletion and sweep efficiency. Early water breakthrough may become a threat to the success of the campaign. Application of smart completion on a new injector may help optimizing the final recovery on the West Flank panel, intelligent completion providing the availability to selectively steer water injection into zones where it is most needed at a particular time. First, the phase IV wells are analysed to choose the best candidate for smart completion application leading to retain one horizontal producer and one horizontal injector in West Flank panel The study was performed using a history matched ECLIPSE 300 ® reservoir model of West Flank panel. The study shows that the installation of ICD or ICV improves the well recovery factor by 10 to 15% and the overall field recovery factor by 1%. The simulation results show that smart completion application in the injector well improves the recovery from poor permeability region by 11 %. An important aspect of the work reported in this paper is also to test the proposed smart completion strategy against uncertainties on reservoir properties. Simulation results show that smart completion is more flexible facing different geological uncertainties.