Cause Analysis on Galling and Corrosion of Stainless Steel Tubings in Well DN2-12 after Acidification

The stainless steel tubings had serious galling and corrosion after two times of acidification operation in well DN2-12. A thorough investigation on two times of acidification operation in the well was carried out, and found that most tubings galling and part tubings corrosion by inspecting the tubings after acidification. It is considered that the tubings galling was caused by improper operation per macro analysis on galling morphology and statistic analysis on galling position. It is thought that there was corrosion concentration at the tubings joints that was related to joint design and machining precision by analyzing corrosion morphology. Tubings corrosion was related to the corrosion medium in the acidification liquid and CO2 in the well gas, as well as the stress state.