Enhanced Vision (EV or EVS) and Synthetic Vision (SV or SVS) are two totally different things in current technology.
EV enhances something that is seen, though poorly (fog, haze, etc), with assistance and image enhancement.
SV is purely that - synthetic, not real, created from a database and displayed as a "virtual" scene. It can display terrain with elevation relief (from a terrain DB) and obstacles (from an obstacle DB). Terrain is quite accurate but obstacles are basic geometric symbols.
Current SV technology, as good as it is, would not be of much help in the offshore environment. Not much "terrain" to look at. It could have offshore obstacles (if in the DB), but not a realistic display of each individual rig, etc. Then, any movable obstacles obviously would be an uncharted hazard.