Electrodeposition of Double Chromium Plating to Improve Corrosion Performance of Screw Drilling in Chloride Environment

Abstract

To adapt to and satisfy rising energy demand, oil and gas exploration and production are gradually spreading to locations with poor underground conditions, and the demand for screw drilling instruments is rising as well. When underground drilling tool materials are subjected to these harsh operating circumstances, they corrode severely and may even cause drill pipe breakage and blowout incidents. Failure due to corrosion is still the most common type of failure, with drilling fluid being the leading cause of downhole drilling tool corrosion and equipment damage, particularly in high-temperature and high-pressure working conditions with higher corrosiveness, which must be avoided and controlled. Double chromium was successfully plated on the surface of the screw rotor using the electrodeposition method to extend the service life of screw drilling instruments. Electrochemical methods such as scanning electron microscopy, open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization curve were used to analyze the plating’s morphology and corrosion resistance. The research results show that at high chloride concentrations (50g/L∼100g/L), when the chloride ion concentration is 60g/L, corrosion resistance is the lowest, and that double chromium plating enhances threaded drilling tool corrosion resistance. The dual chromium plating’s polarization resistance has been enhanced by 18 times. The double chrome plated milky white chrome plating functions as a physical barrier to prevent corrosive substances from diffusing to the substrate interface, corrosive ions from reaching the substrate, and considerably improving the screw rotor’s anti pitting performance.