According to maritime intelligence service Dryad Global, up to 11 personnel may have been kidnapped from the vessel.
The attack is unique within the wider realm of piracy incidents offshore West Africa, Dryad said, with both the manner of attack and target beyond those usually attempted by pirate action groups in Nigeria.
Three vessels were reportedly involved, one of which was used as a decoy to distract the security vessel Hudson Capt Eledu. The other two vessels approached the FPSO and are then thought to have boarded it by attaching a hooked ladder onto the halfway hoisted gangway.
Explosives may also have featured in the attack, a tactic more normally adopted by militants.
In recent weeks, Dryad said, various militant groups in the Niger Delta region have issued statements condemning the actions of the federal government. One group is said to have withdrawn a ceasefire that it previously negotiated with the government.
It appears likely that if personnel have been kidnapped they will be held for ransom. On the other hand, if this turns out to be an act of militancy, negotiations will likely also focus on political concessions tied to the release of personnel and cessation of activity, Dryad suggested.