Scale Inhibitor Residual Analysis: Twenty-first Century Approach

Abstract Control of inorganic scale deposition within the near well bore area under both natural depletion and injection water support has been a challenge to the oil industry for a number of decades. The application of scale inhibitor squeeze treatments to production wells to control the onset of inorganic scale within the near-wellbore and production tubing has been a common practice within the onshore and offshore oil and gas industry for over 30 years. The development of subsea fields require scale inhibitor squeeze treatments with extended squeeze lifetimes while limited number of flowlines to the host facility has increased the difficulty in obtaining and evaluating individual well water samples from which residual scale inhibitor concentrations are derived. Traditional analytical techniques, while robust and widely accepted, do not provide differentiation between scale inhibitors that belong to the same chemical family (i.e.: two or more phosphonates or two or more polymers). The individual analysis of phosphonate scale inhibitors in co-mingled flow backs from subsea wells is a particularly challenging application for analytical techniques in the industry. Advances in separation and mass detection techniques, however, provide new options to accurately measure the concentration of scale inhibitors in these fluids to very low detection limits. This paper will describe the analytical development of these new techniques and discuss its implication to the optimization of scale squeeze treatments in subsea, deepwater developments.