Failure Analysis of Oil-gas Transportation Pipeline with Insert Temperature Transmitter Sheath

The failure morphology and corrosion products of a temperature transmitter sheath and the pipe around it were analyzed by SEM, EDS and X-ray diffraction. The simulated flow field of the pipe was used to find the failure reasons. The results show that FeCO3 was the main corrosion product; and the flow rates of both gas-liquid and two-phase flow were bigger than 15 m/s, which caused serious erosion. The failure of carbon pipe was caused by both the CO2 corrosion and the fluid erosion. According to the failure reasons, several measures to avoid and relieve the failure of temperature transmitter sheath such as adjusting the insertion angle of temperature transmitter sheath, using sticker wall sheathing jacket instead of plug-in one were put forward.