Abstract: Based on a platform in Weizhou, a water-conducting conduit was used for field test. The wall thickness measurement and ultrasonic guided wave corrosion detection were used to determine the corrosion and pitting position and crack depth of the water-conducting conduit. The results show that due to the combined effects of waves, dissolved oxygen and lighting, the water-conducting conduit was more seriously corroded in the tidal zone and splash zone. Risk assessment, life prediction and repair of the water-conducting conduit were performed respectively, and the results could provide technical guidance for the reuse of old wells in other oil and gas fields at sea.