Experimental and Modeling Study on Enhancement of Squeeze Treatment in Sandstone by the Addition of Zinc Ion

Abstract

Abstract Scale inhibitor squeeze treatment is often used to control mineral scales in the oilfield. However, the performance of scale inhibitor squeeze treatment is sometimes not satisfactory due to low inhibitor retention in the formation and a short squeeze life. It has been previously found that the addition of transition metal ions increased the retention of phosphonate and carboxylate polymeric inhibitor in carbonate formation. In this study, laboratory squeeze experiments were conducted to evaluate squeeze treatment by the addition of metal ions (zinc) in Berea sandstone and oil field core materials. Several scale inhibitors including phosphonate, phosphinopolycarboxylic acid (PPCA), and phosphonated carboxylate polymer were investigated, and these scale inhibitors were mixed with metal ions in the inhibitor pill for squeeze application. Experimental results demonstrated that zinc ions in the inhibitor pills improved retention of scale inhibitors and increased squeeze life significantly. It is proposed that the metal-inhibitor precipitate or complex formed, and the formation of the precipitate/complex enhances the adsorption of scale inhibitor in the mineral matrix. It was also found that chemical composition of the mineral may have an impact on the performance of squeeze treatment, and high concentration of iron may limit the effectiveness of this treatment. The demonstration of metal ions to improve scale inhibitor squeeze will have significant implications on scale control in the oilfield.