Evidence of PDMS-based foam control agent mechanism on crude oil foams

Abstract

Crude oil foam is a frequent problem faced in oil production operations that can cause the reduction of the separator efficiency, separator overflow, carry out of liquid by the gas stream, and other serious problems. Among the techniques used to attenuate foams in crude production, the injection of chemical additives is still considered one of the most efficient. However, the effectiveness of a foam control agent (FCA) is limited to the knowledge of its mechanisms of action on crude oil foams. In this work it will be presented a new apparatus and methodology to produce foams with crudes in the range of 20 – 30 °API densities and discuss the experimental data focusing on the mechanism of antifoam/ defoamer mechanism. The study was performed with two crude oils in the temperature range of 25 – 55°C and FCA concentrations up to 75 ppm of a foam control agent (FCA) PDMS based. The experimental results indicated a distinct mechanism of FCA action on both oils. While the FCA caused a decrease in the initial foam height for the heavier crude (oil A), acting as an inhibitor, for the lighter crude (oil B), it mostly performed as a defoamer, i.e., increasing the bubble collapsing rate and reducing the total amount of time spent collapsing.