Root causes of the disaster may not be known for some time, yet it is a stark reminder that good mud logging practices play a vital role in maintaining control of a well, writes Hamid Elwafi, HSEQ officer, Geoservices Libya, Tripoli.
Geoservices was not on board, but comments on the need for sustained awareness of hazards of drilling in a high pressure and high temperature environment. Good well monitoring practices include these procedures;
* Monitor mud density or Equivalent Circulating Density, estimated formation pressure or bottom hole circulating pressure, and maximum acceptable gas levels, during each phase of drilling.
* Observe gas, drilling fluid pit volumes, and return flow rates closely.
* Question changes in these parameters with drilling and supervisory personnel.
* Verify signs of pressure imbalance by flow checks and correlation with other pressure indicators.
* Initial signs of pressure imbalance, such as gas expansion in a riser, may be very subtle. Do not assume that small increases in flow or pit volumes are insignificant.
* Monitor non-drilling operations, such as casing and cementing, with the same level of attention as drilling or tripping operations. Highlight concerns immediately.
“At Geoservices we are reminded of an article in October 1993 in Schulumbeger oilfield review, by the president of DNV, one of the major leading international companies in the field of quality control and quality assurance, which analyses the world’s most severe incidents like Piper Alpha,” writes Elwafi.
DNV concluded that 80% of industrial accidents are ascribed to human error due to incorrect procedures, and that human error includes poor management procedures and decisions.
“The current oil well monitoring alert hints that ‘human error’ or organisational error applies here. We should continue to discuss our procedures and potential incidents during base, field, and ML safety meetings.”
The deep water oil platform burned for more than a day after a massive explosion sank into the Gulf of Mexico in April. Sinking of the Deepwater Horizon, which burned violently until the gulf itself extinguished the fire, could unleash more than 300 000 of gallons of crude a day into the water, reported Associated Press. The environmental hazards would be greatest if the spill were to reach the Louisiana coast, some 50 miles away.
Crews searched by air and water for the missing workers, hoping they had managed to reach a lifeboat, but one relative said family members have been told it’s unlikely any of the missing survived the blast. The Coast Guard found two lifeboats but no one was inside. More than 100 workers escaped the explosion and fire; four were critically injured.
An alarm sounded and the electricity went out, sending workers scurrying to a lifeboat that took them to a nearby service boat. They waited for as many people as they could before casting off.
As the rig burned, supply vessels shot water into it to try to keep it afloat and avoid an oil spill, but there were additional explosions two days after the initial event. Officials had previously said the environmental damage appeared minimal, but new challenges have arisen since the platform has sunk.
The rig carried 700 000 gallons of diesel fuel, but that would likely evaporate if the fire didn’t consume it.
At the worst-case figure of 336 000 gallons a day, it would take more than a month for the amount of crude oil spilled to equal the 11 million gallons spilled from the Exxon Valdez in Alaska’s Prince William Sound.
The well will need to be capped off underwater. Coast Guard Petty Officer Ashley Butler said crews were prepared for the platform to sink and had the equipment at the site to limit the environmental damage.
Oil giant BP, which contracted the rig, said it has mobilized four aircraft that can spread chemicals to break up the oil and 32 vessels, including a big storage barge that can suck massive volumes of oil off the surface.
Those who escaped did so mainly by getting on lifeboats that were lowered into the gulf. Weekly emergency drills seemed to help, he said, adding that workers apparently stuck together as they fled the devastating blast.
Coast Guard Petty Officer Kevin Fernandez was the flight mechanic on a helicopter that was the first to respond, about 15 minutes after the explosion. Fernandez said he could see the fire from 80 miles away, with flames rising about 500 feet.
“I was kind of expecting worse” in terms of fatalities, he said. But survivors already had made their way from the lifeboats into a supply boat. Fernandez and his crew plucked two critically injured survivors to a nearby rig that had a paramedic on board.
Family members of two missing workers filed separate lawsuits Thursday accusing Transocean and BP of negligence.
The USA Minerals Management Service, which regulates oil rigs, conducted three routine inspections of the Deepwater Horizon this year, in February, March and on April 1, and found no violations, MMS spokeswoman Eileen Angelico said.
Rose has said the explosion appeared to be a blowout, in which natural gas or oil forces its way up a well pipe and smashes the equipment. Precisely what went wrong is under investigation.
Transocean spokesman Guy Cantwell said 111 workers who made it off the Deepwater Horizon safely after the blast were ashore Thursday, and four others were still on a boat that operates an underwater robot. A robot will eventually be used to stop the flow of oil to the rig.
Seventeen workers brought to shore Wednesday suffered burns, broken legs and smoke inhalation. Four were critically injured.
Rose said the crew had drilled the well to its final depth, more than 18 000 feet, and was cementing the steel casing at the time of the explosion. They had little time to evacuate.
There are 90 rigs in the offshore Gulf of Mexico either drilling wells or performing work on existing wells, according to the MMS. Working on offshore oil rigs is a dangerous job but has become safer in recent years thanks to improved training, safety systems and maintenance.
Since 2001, there have been 69 offshore deaths, 1349 injuries and 858 fires and explosions in the gulf, according to the Minerals Management Service. Coast Guard Senior Chief Petty Officer Mike O’Berry said accidents are rare given that 30 000 people work on rigs there every day, reported Associated Press.
Safety precautions are described as ‘extreme’. A testament to that is 126 115 former oil rig workers alive and well.