Multifunctional floating dry tree cylindrical FPSO (Floating Production Storage and Offloading) and use method thereof

The invention relates to a multifunctional floating dry tree cylindrical FPSO (floating production storage and offloading) which comprises a ship body, a moon pool penetrating through the center of the ship body and an upper module mounted on the ship body. The circular-truncated-cone-shaped transition section is installed on the heaving body; the cylindrical barrel is mounted on the circular truncated cone type transition section; the interior of a whole formed by the circular-truncated-cone-shaped transition section and the cylindrical barrel is divided into voids, crude oil cabins and ballast water cabins, the voids are symmetrically arranged on the outer side of the moon pool, one part of the crude oil cabins and the voids are annularly arranged on the outer side of the moon pool, and the other part of the crude oil cabins are annularly arranged on the outer sides of the voids; the water ballast tank is annularly arranged on the outer side of the crude oil tank; the outer floating structure is installed a