Survey Practice of Submarine Pipeline In-Position State

According to the difference in survey equipment carriers, the survey methods of submarine pipeline in-position state can be classified into three types: shipborne survey, AUV survey and ROV survey. The shipborne survey is commonly used in the shallow water areas, the AUV survey is adopted in the deep water areas and the ROV survey is conducted in the key areas screened based on the above two surveys. Finally, the overall analysis and evaluation are carried out. Such a combination mode of shipborne/AUV+ROV can well realize the complementary advantages of various investigation methods. It is the first time that AUV is used to investigate the submarine pipelines in-position state. The results obtained by using these methods include the position, the buried depth, the other submarine obstacles distributed around the pipelines and the manual handling status of the pipelines. All these can provide important basic data for the future pipeline maintenance. This successful practice has provided valuable experiences and references for the future similar surveys of submarine pipeline in-position state from the shallow waters to the deep seas.