Abstract: The oil,gas and water produced by offshore oil and gas wells need to be transported through submarine pipelines to onshore processing plants,offshore floating production storage and offloading units,or central processing platforms for treatment. Due to various factors such as crude oil properties and viscosity,wax or dirt will form on the pipe walls of submarine pipelines after a period of transportation. This paper elaborates on the principles and characteristics of online,abandoned and storage,and variable diameter submarine pipeline cleaning technologies,introduces and explains the cleaning methods for submarine pipelines with different media,and compares their advantages and disadvantages.

Key words: submarine pipeline, cleaning technology, transportation efficiency, submarine pipeline sphere pig