Corrosion Reasons and Prevention Measures for Tubing of Water Supply Well in J Oilfield

Corrosion perforation occurred frequently for the tubing of a water supply well in J oilfield after three years of production. Actual operating condition of production field and corrosion characteristic of the tubing were analyzed. And the mechanism of corrosion perforation of the tubing was studied by dynamic simulating corrosion test. At last corrosion protecting measures were proposed. The results show that the produced water from the well with certain scaling tendency and corrosiveness caused the slight scaling and corrosion of nitrided N80 steel tubing. The existence of acid gas and the increase of flow rate resulted in severe asymmetrical scaling and under-deposit corrosion. As production progressed, the situation of scaling and under-deposit corrosion in the tubing became worse, which finally gave rise to perforation failure of the tubing. To extend the service life of the tubing, it was suggested to replace the tubing material with 3Cr steel, use sacrificial anode short piece and get rid of scaling and corrosion products in well.