The South Arne field, located in the Danish sector in the North Sea, has been produced since 1999. The field is Operated by Hess with Dong energy and Danoil as partners. Initially, the field was developed with production wells only but water injectors were added after 1½ years which increased the recovery potential of the field significantly. Currently the field is operated with 20 wells (7 injectors and 13 producers). All wells are fitted with sliding sleeve doors that allow zones to be opened or shut. This provides the valuable opportunity (or obligation) to pursue a more efficient recovery of oil by manipulating sliding sleeve doors – both in injecting and producing wells. In order to understand the long term effects from such well interventions a full field streamline simulation model has been built that will allow the injection efficiencies of individual zones to be quantified. Knowing the injection efficiency of zones enables the right zones to be chosen for interventions and to optimize the overall field water injection efficiency. The main goal has been to reduce water recycling and improve the macroscopic sweep by diverting flow from injectors into less swept areas. An associated benefit from reducing water recycling is the reduced need for lift gas, that can then be allocated to other wells.

It will be shown how an existing conventional simulation model was adapted to a streamline simulator and how this model was used to predict future optimal interventions in injection wells to optimize oil recovery. Excluding the positive effect from freeing up lift gas a ∼1% increase in oil recovery is expected from relatively few yearly interventions.

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