Toward Developing Non-Corrosive Acid System for Complex Scales Removal

Oil and gas industry deals with fluid streams with different ions and concentrations that might cause scale precipitation. The scale precipitation, will thereafter, affect the fluid flow characteristics. Many problems will be raised by the scale deposition that affects the overall petroleum production. This paper aims to develop a non-corrosive acid system with high dissolution efficiency for field complex scales. The paper provided a series of lab analysis that covers the compositional analysis for the collected scale sample, and evaluating the developed acid system for compatible and stable properties, dissolution efficiency, and the corrosive impact. A field scale sample that has a composite chemical composition of calcium carbonate, calcium sulfate, kaolinite, barium sulfate, magnetite, and halite with different weight percentages by employing the diffraction of X-ray technology. Developing the new scale dissolver was achieved by specific compositional study for the organic acids to achieve high dissolution efficiency and low corrosive impact for the field treatment operations. The study results showed the successful scale removal for the developed dissolver at 160 and 210 °F by dissolution efficiency 100 % for 5 hours. The fluid showed a stable and compatible performance with low rate of solids precipitation after the scale treatment (2.3 %). The developed dissolver has a pH of 9. The corrosion test was conducted without any scale inhibitors and the results showed the low corrosion effect by 0.0129 lbm/ft². The obtained successful results will help to dissolve such complex field scales, maintain the well equipment, and maintain the petroleum production from scale issues.