The development of oil and gas reservoirs in the deep water environment is playing an increasingly significant role in supporting the global energy demand. Oil field scale is an important aspect of flow assurance that determines continuous production from reservoirs, because improper scale management could result in astronomical losses. Currently most commercial software packages for scale prediction and risk assessment use stand-alone thermodynamic models that rely on water composition data as input parameters. As seawater injection has become an integral part of deepwater development, the coupling of scale modeling with reservoir simulation becomes necessary to not only track scale reactions and precipitation in the reservoir, but also to assess scaling risks in production wells and surface facilities as a result of the these reactions. Appropriate treatment strategies can thus be recommended based upon simulation results. The scale reaction for barium sulfate (BaSO4) has currently been implemented as a coupled option in our in-house reservoir simulator, CHEARS. Besides conventional reservoir simulation results, the model also outputs scale related information, such as barium and sulfate scaling ion concentrations, the amount of barium sulfate precipitation, scaling tendency of barium sulfate, as well as the time and extent of injection water breakthrough over years.

The scale model in reservoir simulation has been validated using both literature data (Delshad and Pope, 2003) and field data from one of Chevron's assets. The recommendations for scale control based upon the simulation results are in good agreement with field operation. Scale modeling in reservoir is expected to provide a more precise evaluation of scaling risks under challenging production conditions, and a more realistic recommendation for scale squeeze treatment. With the continuous advancement in deepwater development, scale modeling in reservoirs should be an integral part of reservoir management. Reservoir management strategies will be implemented in the field development with the collaboration among experts from different disciplines such as reservoir, scale, flow assurance, production, and process engineers.

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