Assessment of the Performances of Carboxylic Acid Monomers as Fluid Loss Additives for Oil-Well Cement

Abstract

The application of polycarboxylic acid as a fluid loss additive for cement (i.e., a substance specifically designed to lower the volume of filtrate that passes through the cement) can prolong the thickening time of cement slurries. Given the lack of data about the effects of carboxylic acid monomers as possible components for the additives traditionally used for oil-well cement, in this study different cases are experimentally investigated considering different types of these substances, concentrations, temperatures, and magnesium ion contamination. The results demonstrate that itaconic acid has a strong retarding side effect, while maleic and acrylic acids have similar influences on the thickening time of the cement slurry. The rheological properties of the cement slurry tend to deteriorate when the carboxylic acid monomer content in the fluid loss additive is increased to 40%. If the temperature exceeds 80°C, there is a significant decrease in the related impact on the thickening duration. With an increase in the intrusion of magnesium ions to >0.5%, both the rheological properties of the cement slurry and the thickening time are affected in a negative way.