With the development of deep-sea oil and gas development and LNG trade, floating offshore units have become crucial infrastructure for marine energy projects. While they all resemble large ship platforms, their functions differ. FPSO is responsible for crude oil production, processing, storage, and offloading; FLNG is responsible for natural gas liquefaction, storage, and offloading; FSRU is responsible for LNG storage and regasification; FPU is primarily responsible for offshore oil and gas production and processing. FSU stands for Floating Storage Unit, which only performs storage functions and should not be confused with FPU.