A platform on the Norwegian Continental Shelf with extremely saline produced water was encountering persistent scale issues despite the deployment of a new third-party scale inhibitor. Historically, sulfate and sulfide scale was the predominant challenge, but after deploying the new product, analyses of solid samples revealed substantial amounts of apatite scale (Cax(PO4)y).
Increasing the amount of inhibitor worsened the problem. This correlation was explained by an examination of the chemical’s material datasheet, which revealed that the formulation contained a source of phosphorus and was clearly playing a role in apatite precipitation. The operator reduced the inhibitor dosage but then faced a rapid increase in sulfate scaling.
To address the challenge, SLB proposed its new scale inhibitor—SI-41057—and the operator agreed to conduct a field trial. Data collected during the rigorous testing process was collated and showed significantly reduced scale deposition. Pleased with the outcome, the operator incorporated SI-41057 into the chemical treatment process on the platform. During the following months, thermography and monthly samples of produced water showed a significant reduction in the amount and size of precipitated scale particles.
As reservoirs are souring and H2S and sulfide scales are presenting increasing challenges on many of the installations on the Norwegian Continental Shelf, SI-41057 has the potential for widespread application in this region.
