OGJ Senior Staff Writer
HOUSTON, July 7 -- Transocean Ltd. evacuated 108 workers by helicopter from its Marianas semisubmersible after the rig took on water July 6 while working off Ghana for Eni SPA.
The Marianas semi, which was moored, was stable on July 7, according to Transocean spokesman Guy Cantwell. Efforts were under way to disconnect the rig so that it could be towed to sheltered water where it could be inspected for damage.
“It could take a week or more” before the rig can be inspected, Cantwell said, adding that the cause of the incident was still under investigation. He said water was being removed from some of the rig’s compartments, but he would have no other details until the rig had been inspected.
“No injuries have occurred,” Cantwell said, confirming that 20 or fewer workers remained on the rig. The Marianas is capable of drilling in 7,000 ft of water to depths of 25,000 ft.
Separately in a research note, FBR Capital Markets analyst Robert MacKenzie said, “We understand the Transocean Marianas rig developed a crack in one of the pontoons while it was hoisting anchors.”
Transocean moved the Marianas from the Gulf of Mexico during the US deepwater drilling moratorium following the April 2010 Macondo well blowout, resulting in a fire and explosion that killed 11 people on Transocean’s Deepwater Horizon semi. BP operated the Macondo well. The Deepwater Horizon eventually sank, and a massive oil spill resulted from the Macondo blowout.
Eni issued no immediate comment on the Marianas. Earlier this year, Eni said the Sankofa 2 appraisal well confirmed potential of the Sankofa oil and gas discovery to become the first development of nonassociated gas off Ghana (OGJ Online, Apr. 12, 2011).
Drilled in 864 m of water about 55 km off Ghana, the Sankofa confirmed 35 m of net gas and condensate pay in Cretaceous sands, Eni said. The Sankofa wells are on a block adjacent and to the east of the West Cape Three Points block.
Kosmos Energy Ltd. of Dallas said the Marianas incident likely will delay Kosmos from drilling the Cedrela well in the West Cape Three Points block. Kosmos issued a July 7 statement saying it delivered a force majeure notice to the government of Ghana and Ghana National Petroleum Corp. The Marianas was scheduled to arrive July 10 for drilling, Kosmos said.
Although Transocean declined to discuss what might have happened, Kosmos said the Marianas “was rendered temporarily inoperable following a reported anchor-handling incident.”
Contact Paula Dittrick at firstname.lastname@example.org.
Transocean evacuates semi off Ghana