Synthesis of Synthetic Brine to Estimate Carbonate Scale Index in Oil Industry

Abstract

The decreased oil production due to scaling in production equipment results in costs. In oil wells, ions such as calcium, barium, carbonate, sulfate, magnesium, sodium, and chloride are commonly present in formation water. Excessive solubility of ions can trigger precipitation or what is often called scale. This study focuses on creating synthetic brine with a composition resembling field formation water as an alternative solution for rapid laboratory-scale measurement of the scale index. In this study focus on carbonate and bicarbonate scale. The stages of the research involves synthetic brine preparation, physical and chemical testing of the brine, comparison with formation water, and calculation of the Stability Index (SI) using Stiff & Davis method. The results indicate that synthetic brine can be prepared based on laboratory analysis of field samples by estimating the materials and masses present in formation water, thus allowing replication using natural or chemical materials in the laboratory while considering parameters such as pressure, temperature, and pH during the manufacturing process. The pH significantly impacts the risk of scale formation, where a slightly basic pH, around pH 8, supports higher concentrations of carbonate ions (CO₃^2-) and bicarbonate ions (HCO₃^-), thereby increasing the risk of scale formation.