Controlling the kinetic versus thermodynamic growth of calcium carbonate scale in the bulk and on surfaces

Mineral scale formation and deposition can cause dramatic and unacceptable safety risks and associated operational costs. It is recognized as a major flow assurance problem affecting production in the oil and gas industry. The current models used to predict scale precipitation are solely based upon thermodynamic data without taking into consideration any kinetic aspects of scale induction times or growth rates. The aim of this paper is to investigate the interplay between kinetic and thermodynamic control of calcium carbonate precipitation in the bulk and on surfaces. Standard bulk jar scaling tests were performed over a range of saturation ratios and temperatures. By analyzing bulk precipitation and surface growth experimental data the strong temperature dependence on the rate of surface fouling and a moderate dependency on saturation ratio has been confirmed. The experimental findings of this study suggest that reducing the kinetics of calcium carbonate precipitation in the bulk solution can under some conditions promote surface deposition.