Posted on 05/05/2010 6:51:46 AM PDT by Nobel_1
Fooled by Randomness
Rigzone CEO, David W. Kent 5/4/2010
www.rigzone.com/news/article.asp?a_id=92780
Even when random circumstances or events contribute to a catastrophe we search for and assign non-random causes. Sometimes a catastrophic event spirals downward to a disastrous outcome. Other times, lady luck steps into the breach and disaster is narrowly averted. We almost always focus on the former.
Most airline disasters occur just after take off or just before landing. US Air Flight 1549 suffered a double bird strike immediately following take-off. By random selection, pure luck, the plane was under the command of one of the airlines' most senior pilots, an Air Force Academy graduate who trained new pilots and conducted air accident investigations for the Airline Pilots Association. You could not have hand picked a more qualified captain to be at the helm. Instructions from the ground were clear, "proceed south, and turn due north for Teterboro." The captain responded without hesitation and just as clearly, no thanks, "we will be in the Hudson." And, what about the weather? It was perfect. Cold, but visibility unlimited. The initial hit could have easily resulted in a disaster but the stars seemed to line up in favor of a life-saving recovery.
A year later, Air France 447 reported level flight at 36,000 feet three hours after take off. Minutes later, the plane crashed into the Atlantic killing all 256 people onboard. The stars lined up once again, but this time they pointed straight south as circumstances conspired against the plane and crew. One small technical failure was followed by a series of weather circumstances, pilot errors and mechanical failures that led to tragedy. It is worth noting that neither the Brazilian nor the French governments ordered a suspension of all future flights until the cause of the disaster had been determined. That, of course, would have been an inappropriate response.
The Transocean Deepwater Horizon had been working for BP since it was delivered in 2001. Transocean was being paid $500,000 per day to provide a fully crewed rig capable of operating in water depths up to a maximum of 10,000 feet and drilling depths up to 35,000 feet. The rig had started drilling operations at British Petroleum's Mississippi Canyon Block 252 location in February 2010. By April 20th, drilling operations had been successfully completed. Successful from Transocean's point of view in that they had drilled and cased the hole to the depth called for by BP's well design program, and from BP's point of view in that they had drilled into a commercially viable oil and gas pay zone. But on April 20th there was work left to do before the rig could mobilize from this location to the next drilling site. The actual "To Do" list might have looked something like this:
- Run 5" production casing to the total 18,000 foot well depth
- Cement the production pipe and set temporary cement plugs at various depth intervals
- Land the wellhead seal and hanger assembly
- Function and pressure test Blow Out Preventors (BOPs) and top of wellhead seal assembly
- If test successful, displace 5,000 feet of mud in the riser with seawater
- Open BOP ram
- Pull riser and BOP up to the rig
- Done
Something went wrong sometime during the time-line of these procedures. And while the first event may not have caused the deadly blowout and fire, it did likely herald a sequence of other events that led to the explosion, fire, crew deaths and eventual rig capsize. From an interview with one of the surviving crew members on yesterday's Mark Levin Radio Talk Show, it is clear that the drill crew had almost no time to respond. The BOP and wellhead hanger assembly test was apparently successful. The 5,000 feet of drilling mud in the riser pipe above the BOP had been displaced with seawater, but as soon as the BOP was opened the entire 5,000 feet of seawater in the riser unloaded under enormous pressure. Perhaps the initial event was the result of a mechanical failure or human error. The precise sequence of events won't be available until the accident investigations are complete. However, from what is already known, it appears that an unusual convergence of events and circumstances, some random and beyond anyone's control, contributed to the final outcome or at a minimum the magnitude of the tragedy. For example, given what was about to happen as soon as that BOP ram was opened, the weather could not have been worse...dead calm. Had the wind been blowing 20 knots, as it does as often as not in the Gulf of Mexico this time of year, gas may not have accumulated, ignition would not have occurred or would have been delayed, providing a gift of time, to coin a phrase from the USCG...time for the crew to respond, enough time to close the BOPs, or enough time to escape the rig floor.
The two most experienced and senior men on the rig were BP's Company man and Transocean's Offshore Installation Manager. Typically, their day starts at 5:00am. With operations proceeding according to plan, no sign of trouble, and the night tool pusher tasked, they had probably retired for the night. So the weather is horrible and the senior captain is not on the flight deck, what other stars might have lined up in a southerly direction to foil a last minute recovery? Consider if you will, that perhaps the BOPs worked fine. After all, they had just opened without a problem; there is no reason to think they wouldn't now close, unless the drill crew never had time to press the close button. The seawater and drilling mud is roaring out of the hole and has covered the rig floor lights; the noise is so loud you cannot hear yourself scream. You are effectively blind and deaf, covered in oil-based mud...now go close the BOPs.
BP is one of the world's most experienced deepwater exploration companies and Transocean is the largest offshore drilling contractor with an outstanding safety record. The technical challenges are enormous, but these two companies will no doubt marshal the assets and expertise required to clean the spill and kill the well.
Personal comment - with 20-20 hindsight, the engineers should have employed a secondary blowout system from a different manufacturer with a failsafe remote trigger.
A BOPBOP?
Why not a BOPBOPBOP?
Interesting article, but editorials aren’t “Breaking News.”
You make a good point--adding complexity to the system, even if it's "failsafe" measures, doesn't necessarily increase the reliability or safety of the system.
BP self-ping, and thanks for posting this, Nobel_1.
WBAP Dallas / Mark Davis - transcript of first-hand account of accident ... http://www.rigzone.com/news/article.asp?hpf=1&a_id=92765
BTTT
I cannot imagine that standard hazard review procedures would not have such a valve already, so I'm wondering about some of these procedural details in the article. Certainly the seawater would become saturated with natural gas thus requiring the purging process be executed with adequate ventilation; inadequate air exchanges and no go. So if there was no wind, why did they go ahead?
Not to monday morning quarterback but the industry should have one of these blow out cones they are building now to drop on a leak. It appears to just be a huge iron or steel cone. I would guess at the top there is a valve that can suck out the oil. It seems like it is just a huge and heavy piece of metal.
Avoiding disasters is a better option but this thing could have been dropped on the leak after two days. I realize it does not solve the problem but reduces the chances of a spill or reduces the time of a spill or leak to about 2 days. Have one on the docks in TX or LA and have ships in the area available to move quickly.
The acoustic device discussed is not a separate BOP.
It is another set of switches for remotely activating the same BOP. Since the BOP won’t work from direct operation from the main control panel on the BOP, another remote switch trying to trigger the same set of valves will not help.
Think of it this way. If the main breaker of the electrical panelboard in your house is off, adding light switches inside the house is not going to get the lights on.
From the Mark Davis / WBAP first-hand account (see http://www.rigzone.com/news/article.asp?hpf=1&a_id=92765 for transcript), it appears the BOP had just passed a test, and they had displaced the mud with sea water ... which was when the gas bubble (”kick”) occurred under high pressure.
The sea water was blown out the top of the rig, and the gas (heavier than air) decended and found an ignition source. Crew raced to life boats after initial explosion ...
and where the hell was bummer’s bopbopbop czar when all this was going on????
Good info ping
BOPS can’t close if blocked by something the shears can’t cut.
and that is the problem at this time.
you can have all the switches you want...ain’t gonna matter
I suspect you DON’T work in the oilfield and don’t understand WHAT BOPS are used for.
The metal dome will have a spot on the top with flanges, they will attach COFLEXIP hose to it.
They will try to guide that escaping oil from the damaged well head up into the metal funnel and they hope the pressured oil will be pushed up one mile in an oil stream to be collected at the surfaces boomed in and with a collection method.
So instead of a CLOUD of oil coming up to the surface, it will be a controlled (they hope) column of oil surfacing.
WE will see.
Two mitigation thoughts came from offshore people at the OTC conference this week ... one was a dual-BOP setup, using different technologies on each with deadman switches.
The second idea was simply to adopt the “Norway standard” with remote signalling capability.
(Some BOP history for those of you who are interested ... in 1922, James Smither Abercrombie and Harry S. Cameron invented the ram BOP in Humble, TX. Their invention sealed off a well using a sharp horizontal motion. The first ram BOP was controlled manually, and quickly became an industry standard. Early BOP designs could withstand pressures up to 3,000 psi. Today’s average BOP can withstand 15,000 psi in water depths up to 10,000 ft.)
You can have all the remote signalling capability in the world and it won't make a bit of difference if the BOP is not mechanically functioning or is physically blocked from doing so.
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Remote Acoustic BOP