Saipem S.p.A. reported Tuesday that the Perro Negro 6 sank offshore Angola after the seabed collapsed under one of the rig's three legs.
The rig sank Monday night while being positioned for drilling operations near the mouth of the Congo River at the border of Angola and the Democratic Republic of Congo in approximately 130 feet (40 meters) of water, Saipem said in a press release.
One hundred and three workers were on board the rig when the Perro Negro suddenly tilted, causing the rig to take on water and capsize. One crew member is missing, and six other workers suffered minor injuries, Saipem reported.
Saipem's emergency response team is working closely with the Angolan authorities and the client's operational team, Saipem said.
The Perro Negro is under contract with Chevron Corporation through early 2015 at a day rate in the upper $110,000s.
