Enhancing the efficiency of scale inhibitor squeeze for mature fields of the Campos Basin-RJ using Ca2+ bridging ion

The Campos Basin is one of the main sedimentary areas already explored in the Brazilian coast, with mature fields in an advanced stage of production, some of which use seawater injection as recovery method. Injected seawater and formation water may be incompatible and, with production, precipitate insoluble inorganic compounds, in this case barium and strontium sulfates (BaSO4 and SrSO4). The main method of preventing scale in the reservoir is periodic scale inhibitor squeeze surrounding the production well. In this work, coreflood laboratory tests were performed using phosphonate inhibitor and Ca2+ as an additive. The objective was to assess Ca2+ as an additive to increase the squeeze lifetime, reducing well interventions for the sandstone reservoirs of the Campos Basin. The results showed that Ca2+ as an additive resulted in an increased performance of the scale inhibitor squeeze treatment.