Due to the increased cost of scale management in subsea compared to platform or onshore fields, and because of the more limited opportunities for interventions, it is becoming increasingly important to carry out a risk analysis process for scale management as early as possible in the field development plan. A critical part of this process is to evaluate methods of chemical deployment for reservoirs where near wellbore scale has been identified as a significant risk to production – often leading to consideration of the scale squeeze process.

This paper discusses how scale squeeze treatment deployment options can be modelled and demonstrates the comparison of mechanical and chemical diversion (particulate or viscosified fluids) with simple rate diversion. In subsea heterogeneous wells diversion via bullhead deployable treatments can be more cost effective than deployment via a rig and coil tubing, provided the treatment distribution is as effective. The ability to model the application process is critical in the economic assessment of coil/rig vs. fix facility deployment in deepwater fields.

The paper will outline the process of chemical selection, reservoir/near wellbore modeling and field application for solid, viscosified divertors or deployment options where high pump rates are utilized to achieved better chemical placement.

Field treatments where this process has been utilized (North Sea, Brazil and West Africa) will be presented along with the results of these treatments. Practical issues related to overcoming the challenges of subsea flow line cleaning and the effective rates required to achieve diversion are discussed, as are monitoring methods following such treatments to ensure effective placement has been achieved.

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