Demulsifiers for crude oil based on acrylic-aminoacrylic random copolymers of controlled molecular mass

Abstract

Nowadays, one of the major problems of the oil industry is the presence of large amounts of water and salts, which cannot be efficiently removed by conventional dehydrating polymers. In addition, the acid stimulation operations of petroleum wells cause the chemical degradation of demulsifiers such as polyethers and phenolic resins, reducing drastically their efficiency as water and salt removers. Based on aforementioned, a series of new copolymers has been developed; these copolymers are combinations of an acrylic and an aminoacrylic monomer and they are synthesized by semi-continuous emulsion polymerization (under starved feed conditions), which ensures both the homogeneity of the different chains as well as the randomness of the monomers distribution. The solutions of one of these random copolymers have shown an efficiency similar or superior to combinations of two or three block copolymers (formulations), when they are applied in light or heavy crude oils. The acrylic-aminoacrylic copolymers show good performance as water/oil emulsion breaker initiators, coalescence agents of water droplets and clarifiers of the remaining aqueous phase. In addition, the chemical structure of the acrylic copolymers confers resistance to degradation induced by abrupt pH changes when acid stimulation operations of wells are performed.