Causes Analysis on Corrosion Perforation of a P110 Oil Tube

The corrosion perforation of a P110 oil tube occurred in a certain well, causing the fracture of the oil tube. The construction work was influenced seriously. In order to find out the reasons of corrosion perforation of the oil tube, the macro morphology, chemical composition and microscopy microstructure of the perforation position were analyzed. The micro morphology of the inner wall and outer wall of the perforation position was observed by scanning electron microscope, and corrosion products were observed by SEM, and the main element compositions of corrosion products of the inner wall and outer wall were analyzed by energy dispersive spectroscopy and X-ray diffractometer. The results show that in the acidic and high Cl- corrosion medium, pitting corrosion occurred in the pin holes defects of coating on the inner wall of the oil tube, resulting in the tube perforation, and then the erosion corrosion happened, accelerating the corrosion rate of the oil tube.