Adaptability evaluation of anti-corrosion oil pipe materials for water injection wells

The study considers the characteristics of complex working conditions of water injection wells in Shengli Oil Field, high salinity and hardness of water injection, corrosive gases, sulfate-reducing bacteria, and other corrosion and scaling factors. By comparing N80, the corrosion performance of four commonly used anti-corrosion tubing in Shengli Oil Field, namely, nitriding, tungsten plating, titanium nano, and titanium molybdenum, was systematically evaluated. Key factors affecting oil pipe corrosion were summarized through the grey correlation statistical analysis method. Corrosive gas is the key factor affecting N80, tungsten plating, and nitriding test pieces. Mineralization is the key factor affecting titanium nano and titanium molybdenum-coated oil pipes. Using N80 as a comparison, the scale formation on the surface of four types of anti-corrosion test pieces was evaluated. The surface of the four types of anti-corrosion test pieces was mainly composed of calcium carbonate scale. Among these, the scale crystal density of nitrided and titanium molybdenum test pieces was high, and the scale adhesion was relatively tight. The density of scale crystals on the surface of titanium nano and tungsten-plated specimens is sparse, and the adhesion is weak. On the surface of N80, there are both calcium carbonate and many corrosion products.