By Oleg Vukmanovic
LONDON, July 11 (Reuters) - Chevron Corp. left workers pleading to be evacuated from a gas exploration platform off Nigeria which kept drilling while smoke poured from a borehole until an explosion killed two people as the rig became engulfed in flames, according to accounts from four of the platform's workers.
Chevron, the second largest U.S. oil major, said it did not receive requests to evacuate the KS Endeavour rig and that staff on board had the right to call a halt to work if they believed conditions were unsafe.
"There were no evacuation requests received before the KS Endeavour incident occurred," the U.S. energy company said in an emailed response to questions from Reuters.
Testimony from some of the 154 workers who were present alleges that, instead of addressing fears that equipment failures and smoke presaged disaster, Chevron flew extra staff to the platform just before the Jan. 16, 2012, blowout.
Chevron says a nationwide Nigerian strike that included staff at airports had disrupted its normal crew changes but that at no time were approved safe manning levels exceeded.
The fire that followed the blast burned on the rig for 46 days until March 2. Chevron drilled a relief well to stem the gas leak, sealing it on June 18. It said in an email to Reuters on July 2 that an investigation with the Nigerian authorities had concluded that an entry of high pressure gas in the wellbore had caused the failure of equipment and fire.
The two who died in the explosion were the installation manager for the rig, Bruno Marce, a French national, and Indian driller Albert Devadas. They worked for KS Drilling, a subsidiary of Singapore-based KS Energy, a sub-contractor employed by Field Offshore Design Engineering (FODE) Ltd to drill a gas exploration well for Chevron off Nigeria.
Transcripts of accounts from three workers were given to Reuters by the offshore oil branch of Britain's Rail, Maritime and Transport (RMT) trade union which said the documents were genuine but withheld the names of the witnesses to protect their employment prospects. Those accounts were backed by subsequent interviews in Nigeria with a worker who was also on the rig.
FODE declined comment, citing confidentiality clauses in its contract with KS Drilling preventing it making public any information about work for Chevron.
The accounts convey rising panic from some of those on the platform, who fearing a blowout, checked each morning the volume of smoke billowing from the drilling borehole.
"Chevron knew for over a week that the well was unstable yet they refused to evacuate us," said one of the rig workers who gave his account to the RMT union.
A Nigerian worker who was aboard the rig at the time of the blast said many wanted to be evacuated.
Speaking at a hotel in Yenagoa, the oil capital of the Niger Delta's oil-rich Bayelsa state, Omietimi Nana, 28, a maintenance worker for FODE said: "We were told we may be evacuated, it was mentioned but it didn't happen. I don't know who made the decision not to evacuate but certainly many people wanted to be evacuated because of the situation," he said.
The most senior witness to give testimony to the RMT, a Frenchman, said a series of pump failures throughout the drilling operation led to a massive build-up of pressure that triggered the blowout.
The Frenchman said rig engineers held a site meeting and advised Chevron to evacuate staff while well pressure control measures were applied.
"That advice was not heeded and additional personnel were even brought onboard to get ahead of what was believed to be impending strike action," the Frenchman, who was at that meeting, said.
Nana added: "About three days before the accident, the drilling company workers told us they wanted to stop drilling because of the gas pressure but they spoke with Chevron who told them to carry on."
The French witness said an earlier failed attempt in late December to drill an exploration well near the same was abandoned after the discovery of a gas leak.
He said that "in an attempt to learn from experience" Chevron began drilling a second well "despite repeated failure of the pumps" and often having to stop drilling in order to service the top-drive, the device on the rig that provides rotational force.
Chevron acknowledged that the first exploration well was abandoned but denied it was because of a gas leak.
"SCARED LIKE HELL"
The second well, drilled 300 metres from the first, at a depth of 12,945 feet (3,946 metres), soon began to lose pressure integrity, the French witness said.
"At almost every point in time, we saw thick smoke coming out of the open hole, and we were all scared like hell because we could see a disaster happening any moment yet they (Chevron) did not evacuate us - why, I do not know," the witness said.
"This is the reason so many of us survived because we were all aware that it was going to happen, but just didn't know when," he said.
FODE maintenance worker Nana said: "Everyone was talking about how the mud weight had been lost but by then it was too late to stop the gas rising to the surface."
Within days, said the French witness, rising gas pressure overwhelmed the mud weight in the wellbore spewing gas over the rig, sending workers scrambling for the lifeboats.
"The blowout occurred on Monday at 5.30 a.m., and if Bruno (Marce, the rig manager who died) had not advised as he did that the lifeboats be kept serviced and in functional condition then none of us would have made it out alive," said the eyewitness.
"Bruno was shouting, but with a very strange voice, over the public address system that everyone should abandon the rig, I really felt for him for if not for his timely intervention myself and others would not have been alive today," he said.
The witness said that by the time he had reached the lifeboat the rig was smothered in gas. When the lifeboat operator called rig manager Bruno Marce for permission to launch there was no reply, he said. The gas exploded and the lifeboat launched.
"By the time we hit the water the entire rig was engulfed by fire," he said, describing metal debris raining down.
A second eyewitness described a deafening release of gas followed by "a loud bang and an orange flash as the gas ignited."
The witnesses described how crew on a barge adjacent to the platform jumped into the water and scrambled into a life raft. The raft quickly began to melt from the heat of the fire, forcing them into the sea to be rescued by fishermen three hours later.
"If it were not for the fisherman those guys would have died in the water," the French witness said.
Asked to respond to the principal points of the allegations, Chevron said it was at no time asked to evacuate staff and that all personnel present had the power to order a work stoppage if they felt they were in danger.
"Our employees and contractor are fully empowered to exercise stop work authority (SWA) when they sense an unsafe work environment," Chevron said, explaining that an SWA gives anyone aboard a rig the power to order a stop to operations in the event safety guidelines are breached.
"At no time was an evacuation initiated by anybody on the rig before the incident occurred," Chevron said.
The union said it believed workers were worried they would lose their jobs if they quit the rig without permission.
"It appears the Endeavour workforce were reluctant to abandon the rig after the evacuation request was denied for fear of losing their jobs," said Jake Molloy, head of OILC, the offshore energy branch of the RMT, which had members on the rig.
Molloy said the installation manager's efforts to prepare lifeboats demonstrated that the danger was known.
"That fear is evident in the actions of the offshore installation manager who, as part of some bizarre 'risk assessment process', opted to ensure the lifeboats were in a state of readiness for what appears to be an inevitable evacuation," the union official said.
Chevron said its rules required that lifeboats should be kept ready at all times and the crew held weekly drills, one of which was scheduled by the Offshore Installation Manager (OIM) Bruno Marce for the morning of the day before the blow-out happened.
"Like any other personnel, the OIM has full responsibility to stop the operation if he feels conditions are not safe," Chevron said.
The company said it had launched a prompt, full rescue effort and the evacuation had been orderly and structured, although it acknowledged fishermen had picked up some workers.
"Search and rescue operations began immediately upon being made aware of the abandon ship alarms being sounded," it said. Nearby vessels were directed to aid the rescue.
"152 of the 154 personnel on board the KS Endeavour and the Mako barge were evacuated immediately. Aircraft operations were impacted initially by darkness and by visibility conditions," it said.
(Additional reporting by Joe Brock in Nigeria, Editing by Richard Mably, Anthony Barker and Giles Elgood)