A preliminary evaluation of inorganic composite profile control and oil displacement agent for high water cut oil fields

ABSTRACT An environmentally friendly inorganic composite deep profile control and oil displacement agent was prepared for high water cut oil fields with formation water containing sodium bicarbonate. Sodium silicate and calcium chloride were used as the main agents, while polycarboxylic acid dispersant and liquid polymer were used as auxiliary agents. The effects of the type of polycarboxylic acid dispersants and the mass concentration of liquid polymer on the performance of deep profile control and oil displacement agent were studied. The results showed that when the acid-ether ratio of the polycarboxylic acid dispersant was 3.7 and its molecular weight was 23800, the electrostatic repulsion and steric hindrance from polycarboxylic acid dispersant and inorganic particles achieved an effective dispersing effect. Combined with low concentration of liquid polymer (500 mg/L), the viscosity and strength of the formulated inorganic composite deep profile control and oil displacement agent could be enhanced. Results showed that this inorganic composite deep profile control and oil displacement agent could increase the flow resistance, with a plugging rate of 82.3%. It could achieve online injection, rapid dispersion, deep profile control and oil displacement with low cost, which showed high potentials in applications in high water cut oil fields.