Evaluating efficiency and stability of calcite scaling inhibitors at high pressure and high temperature in laboratory scale

Abstract

Reduction or prevention of scaling is commonly achieved by injecting scaling inhibitors into the geothermal circuit. Inhibitor-efficiency tests can be carried out in static or dynamic experiment set-ups allowing measurements at high pressures and high temperatures (HPHT). For these measurements, suitable analytical methods have to be selected depending on the nature of the scales and the specifics of the related sensors in a HPHT environment. In this study, a calcite scaling inhibitor was evaluated in static batch tests at HPHT conditions with respect to its inhibitory efficiency as well as its degradation behaviour. The inhibitor efficiency significantly decreases in comparison to ambient p,T-conditions. In a long-term stability experiment, a delayed partial degradation of the inhibitor at HPHT conditions could be observed.