Velesto Energy-owned jackup rig Naga 7 has sunk off the Malaysian state of Sarawak while operating for ConocoPhillips.
The incident occurred at the worksite on May 3 due to rapid penetration into the formation, Velesto said.
The rig tilted and subsequently submerged at the location on Tuesday. Drilling activities have not commenced and no well has been drilled.
All personnel onboard have been reported safe and majority have been transferred to Miri, Sarawak. The remaining personnel are in the process of being transferred.
Velesto said it is investigating the incident and evaluating options while the recovery efforts are ongoing.