Mineral-Scale Control in Subsea Completion

摘要

Deepwater production is characterized by large productionrnrates from thousands of feet below the ocean floor. Multiplernwells are linked to the flowlines on the ocean floor where thernproduced brines from different wells commingle. Suchrnproduction system often increases the challenges of scalernprevention and control. In this paper, a new thermodynamicrnPitzer theory based computer software, ScaleSoftPitzerTM, willrnbe discussed first. ScaleSoftPitzerTM is a MicrosoftTM ExcelTMrnbased program to predict scale tendency, specifically writtenrnfor the oil and gas production systems. Secondly, the effect ofrnhydrate inhibitors on sulfate scale formation will be evaluatedrnover a wide range of temperature and salinity typicallyrnencountered in the oil field. The hydrate inhibitors can reducernthe solubility products of sulfate minerals by more than twornorders of magnitude. A new speciation model is proposed torncorrect the hydrate inhibitor effects in terms of a ionnonelectrolyternmean activity coefficient.