Investigation of Causes for Corrosion of Φ73.02 mm×5.51 mm P110 Tubing

Analyzed in the paper are the causes for corrosion of the Φ73.02 mm×5.51 mm P110 tubing as used in a certain oilfield by means of site-data investigation，macrostructure analysis，metallographic structure analysis， SEM and XRD，etc. The analysis result shows that the primary cause for the tubing corrosion is the co-existence of high contents of carbon dioxide and Cl^-，stratum water and acid fracturing outlet liquid in the well. And the severity of the corrosion is related to the position of the gas-liquid interface and the well section temperature. It is recommended to adopt the anti-CO₂ corrosion tubing and casing.