Application of Integrated Production System Modelling in Effective Well and Reservoir Management of the Bonga Field

Abstract

The Bonga field located offshore Nigeria in OML 118, has produced more than 275 MMstb in the last 4 years. Production rates from 16 subsea high rate oil producer wells from 5 different manifolds are being sustained by waterflooding that was implemented from the onset of production. Currently, mostly single zone oil producer wells drain 5 different deepwater turbidite reservoirs in the field. Fully treated seawater is injected from 13 subsea high rate water injector wells daisy chained onto 2 separate injection lines. Oil offtake on reservoir level is highly dependable on successful voidage replacement and pressure maintenance. In addition, constraints and operating envelopes in both the production and injection system make day-to-day optimizations extremely challenging. As with all waterflood and Enhanced Oil Recovery schemes, 'world-class' Well and Reservoir Management (WRM) is the foundation of a successful project.One key element of effective WRM is the application of Integrated Production System Modelling (IPSM).Advanced and robust tools that model complex integrated systems from the reservoir to the topsides have been developed and applied extensively in the industry. An IPSM was built for Bonga allowing detailed dynamic reservoir simulation models to be linked with well, flowline / subsea and topside models. Both the injection and production network models were incorporated to simulate the actual field situation. In addition, an optimization script was built to manage offtake and distribution of injection water aligned to the field pressure policy. This enables the model to duplicate as closely as possible actions taken in the field. An integrated-discipline workflow was developed and applied on a monthly basis to maintain the Bonga IPSM 'live' through calibration with well test data and update with the latest field information.The 2 key benefits of the IPSM are:• Integration of multi-disciplines (from subsurface to topside) in model update and calibration, and to ensure all aspects are considered for a robust forecast • Testing new optimization opportunities or ideas for improving oil offtake and water injection prior to implementation in the field Examples of successful application of IPSM in WRM are described in this paper, which also highlights future applications of IPSM for the Bonga asset.