**2. The technical challenges of offshore chemical flooding**

Chemical flooding has been successfully carried out in onshore oil fields in China for nearly 30 years. The implementation of traditional polymer flooding technology

requires a large amount of freshwater supply, large injection allocation equipment, good reservoir conditions, and loose environmental requirements. It is difficult to meet these requirements in offshore oil fields. To realize the field application of polymer flooding technology, there are several challenges to overcome to conduct offshore chemical EOR projects:

