Abstract: Thermal production, which is used in Liaohe Oil Field as a main method to explore viscous oil, gives rise to the artificial increase of CO₂ content in the crude produced from well. After CO₂'s dissolving into water, dilute carbonic acid solution is formed, which is corrosive to the gathering lines. Also included in the crude produced are hydrogen chloride, hydrogen sulfide as well as hydrogen. Under this corrosive environment, gathering lines are subject to severe corrosion damages. Through site investigation and techno - econmical comparisons, it is pointed out that corrosion can be completely prevented by applying internal extrued coating on the gathering lines. This coating technology can improve pipeline operation efficiency, reduce costs and prolong pipeline service life, so it is suitable for the internal corrosion control of short distance pipelines.