Ch. Noïk (Institut Français du Petrole) | Ch. Dalmazzone (Institut Français du Petrole) | L. Komunjer (Universite de Technologie de Compiègne)
Oil exploitation is always accompanied by non-desired formation of emulsions due to the presence of naturally occurring surface-active molecules such as asphaltenes and resins. Their presence stabilizes the oil/water interface and therefore, it is necessary to break the emulsions by adding other surface-active molecules. Formulations based on polysiloxane molecules were selected as effective non-toxic products to enhance the oil/water phase separation. Relations between the efficiency of formulations and the interfacial properties of silicone molecules are the objective of this study. Formulation selection is based on bottle tests using turbidimetric measurements and on dynamic tests using a “dispersion rig” set-up. This experimental set-up permitted to reconstitute emulsions under pressure and temperature conditions and then to inject additives into the formed emulsion online. Rapid kinetics of separation as high levels of separated water were observed. Dynamic interfacial measurements were performed using complementary techniques. Drop volume technique allowed to measure the evolution of crude oil/water interfacial tension with time. Langmuir trough technique permitted to obtain two-dimensional compression isotherms as well as the measurement of elastic properties of interfaces. The coalescence of water droplets leading to the destabilization of emulsions and consequently to the water/oil separation efficiency could be related to the rheological properties of water/crude oil interface. Therefore, such comprehensive study based on a specific methodology can lead to a strict and effective selection of emulsion breaker additives in relation with the oil composition.