The Deepwater Horizon Disaster

Deepwater Horizon Oil Slick Estimate

By now you’ve all heard of the environmental disaster in the Gulf of Mexico but my sense is the media (along with BP) is underplaying the scope and size of the disaster. Others like the Governor Perry set it as an “act of God”.

Perry questioned whether the spill was “just an act of God that occurred” and said that any “politically driven” decisions could put the U.S. in further economic peril.

“From time to time there are going to be things that occur that are acts of God that cannot be prevented,” Perry said.

His line of thinking offers a foil to liberal groups and lawmakers who are calling for an immediate halting in off-shore drilling, something that the Obama administration has championed. MoveOn called for President Barack Obama to reinstate the ban on off-shore drilling Monday.

There’s a much more mundane explanation. Dr. Ian MacDonald at FSU just produced a new spill-size estimate based on the U.S. Coast Guard image above. According to Dr. MacDonald, the map implies that on April 28, there was a total of 8.9 million gallons floating on the surface of the Gulf. Backtracking gives us a flow rate of over one million gallons per day blowing us past the Exxon Valdez disaster. A “not public” report by NOAA suggested that the 5000 barrel could be off by an order of magnitude. For reference 50000 barrels would be 2.1 million gallons of oil per day.

The underestimated size of the oil slick is only half of what is not being emphasized in the media. There’s also this story in the Wall Street Journal.

Blowout Protector

The oil well spewing crude into the Gulf of Mexico didn’t have a remote-control shut-off switch used in two other major oil-producing nations as last-resort protection against underwater spills.

The lack of the device, called an acoustic switch, could amplify concerns over the environmental impact of offshore drilling after the explosion and sinking of the Deepwater Horizon rig last week.

The accident has led to one of the largest ever oil spills in U.S. water and the loss of 11 lives. On Wednesday federal investigators said the disaster is now releasing 5,000 barrels of oil a day into the Gulf, up from original estimates of 1,000 barrels a day.

U.S. regulators don’t mandate use of the remote-control device on offshore rigs, and the Deepwater Horizon, hired by oil giant BP PLC, didn’t have one. With the remote control, a crew can attempt to trigger an underwater valve that shuts down the well even if the oil rig itself is damaged or evacuated.

The efficacy of the devices is unclear. Major offshore oil-well blowouts are rare, and it remained unclear Wednesday evening whether acoustic switches have ever been put to the test in a real-world accident. When wells do surge out of control, the primary shut-off systems almost always work. Remote control systems such as the acoustic switch, which have been tested in simulations, are intended as a last resort.

Nevertheless, regulators in two major oil-producing countries, Norway and Brazil, in effect require them. Norway has had acoustic triggers on almost every offshore rig since 1993.

The entire industry has been fighting regulation by the MMS. I checked the WSJ’s assertion about the so-called acoustic switch with industry expert, Bob Cavner, shown being interviewed by Fox News here. It’s amazing all the “reporter” was interested in was the “terrorist” angle. I guess she was taking orders from Rush.

…lest we forget, the carbon tax bill — Cap and Trade — that was scheduled to be announced on Earth Day. Then it was postponed, a couple of days later… what better way to head off more oil drilling, nuclear plans, than by blowing up a rig? I’m just noting the timing, here.

Here’s his response:

There’s actually nothing known as an “acoustic switch”. There is, however, an acoustic control system that does not rely on an umbilical from the rig floor to the BOP [Blowout Protector] on bottom for communication. If this system had been in place, it possibly would have prevented this incident, since if communication from the rig is lost, the BOP automatically closes.

However, if there was a tool, casing hanger, or other obstruction in the shear rams, that would have prevented the BOP from sealing the well, and it still would be flowing.

I believe, though, that this new system should be required on all deepwater drilling operations.

He said the following on his blog today:

Over the weekend, I’ve learned a lot through my own research and through contacts within the industry about BP’s blowout well, Mississippi Canyon Block 252, and, even though BP and Transocean remain silent as to the condition of the wellhead and BOP (blowout preventer), it seems that consensus is growing that the damage to the stack, 5,000 feet below sea level, is serious and likely irreparable. My sources tell me that ROVs have worked directly on the BOP, doing everything that should have activated it and it has failed to close. It is believed that something may have initially jammed the shear rams and they failed to close; however, the BOP was subsequently severely damaged by the stress of the collapsing riser that remained attached as the Deepwater Horizon sank. The riser was 5,000 feet of 21″ diameter pipe, some buoyant, some negatively buoyant, putting huge forces at the stack on the sea floor as it sank.

My understanding is that the flowing wellhead pressure may be as high as 10,000 PSI and that, even if the BOP could be closed now, could very well be leaking in the locking mechanism below the stack. Leaks always get worse, not better, as anyone knows who’s been annoyed by a dripping kitchen faucet. The only problem here is that this faucet is “dripping” at upwards of 25,000 barrels per day. One industry source, who has knowledge of the operations, said, “[the BOP] isn’t closed and In my professional opinion, its not going to close…”

The well has now been flowing uncontrolled for 13 days. As we’ve talked about before, these units are designed to slam shut, not be flowed through, at least at these high rates and pressures. Erosion of the ram faces and the bore is now likely severe, further reducing its chances of ever actually shutting the well in and sealing.

I understand that preparations are now being made to cut the riser above the BOP in preparation of installing the containment structure to control the flow of oil. Essentially, it is a large structure that is lowered over the source of the leak, attached by a riser to the surface. Oil will then flow up the riser to a ship that will process and collect the oil. It is believed that, if successful, this structure could capture 85% of the produced oil. This is a technique that has been used successfully in shallow water, but never this deep. It appears to me that the containment structure is the only chance BP has of slowing the growth of the spill, at least until they get the well killed by a relief well, or if well bore damage slows the flow by itself.

The best comparison of this accident is not the Exxon Valdex but the largest accident ever, the Ixtoc I spill. (The largest spill was deliberately set by Saddam Hussein.)

On June 3, 1979, the 2 mile deep exploratory well, IXTOC I, blew out in the Bahia de Campeche, 600 miles south of Texas in the Gulf of Mexico. The IXTOC I was being drilled by the SEDCO 135, a semi-submersible platform on lease to Petroleos Mexicanos (PEMEX). A loss of drilling mud circulation caused the blowout to occur. The oil and gas blowing out of the well ignited, causing the platform to catch fire. The burning platform collapsed into the wellhead area hindering any immediate attempts to control the blowout. PEMEX hired blowout control experts and other spill control experts including Red Adair, Martech International of Houston, and the Mexican diving company, Daivaz. The Martech response included 50 personnel on site, the remotely operated vehicle TREC, and the submersible Pioneer I. The TREC attempted to find a safe approach to the Blowout Preventer (BOP). The approach was complicated by poor visibility and debris on the seafloor including derrick wreckage and 3000 meters of drilling pipe. Divers were eventually able to reach and activate the BOP, but the pressure of the oil and gas caused the valves to begin rupturing. The BOP was reopened to prevent destroying it. Two relief wells were drilled to relieve pressure from the well to allow response personnel to cap it. Norwegian experts were contracted to bring in skimming equipment and containment booms, and to begin cleanup of the spilled oil. The IXTOC I well continued to spill oil at a rate of 10,000 – 30,000 barrels per day until it was finally capped on March 23, 1980. Keyword: Boom, Corexit 9527, skimmer, manual removal, volunteers, blowout, fire, evaporation, blowout preventer, relief well, submersible..

Prevailing northerly currents in the western Gulf of Mexico carried spilled oil
toward the U.S. A 60-mile by 70-mile patch of sheen containing a 300 foot by
500 foot patch of heavy crude moved toward the Texas coast. On August 6, 1979,
tarballs from the spill impacted a 17 mile stretch of Texas beach. Mousse
patches impacted the shoreline north of Port Mansfield Channel on August 15 and
again on August 18. On August 24, mousse impacted shoreline south of Aransas
Pass. By August 26, most of North Padre Island was covered with moderate
amounts of oil.

As of September 1, all of the south Texas coast had been impacted by oil. A
storm lasting from September 13-15 removed the majority of the oil. For the
remainder of the response and subsequent study period (through August 1980) only
tarmats were observed on the beaches. Some oil escaped around boom barriers
protecting the three major inlets. During the September storm, there was
washing of oil over the Barrier Islands. Impacts to the estuaries were minor.

The similarity between the two spills is striking but there’s a key difference. Ixtoc had human divers while Deepwater Horizon used robots which couldn’t activate the BOP like Ixtoc. The initial BOP failure is stiking. The collar on the pipes kept the shears from severing the pipes in the blowout protector. Note how long it took to cap the well, from June 3, 1979 to March 23, 1980. The flow rate is similar to some estimates of Deepwater Horizon, 10,000 to 15,000 barrels per day. From an engineering perspective this is striking. There’s a single point of failure and no backup plan if the BOP fails. I’ve seen failure rates as high as 50% for the BOPs. Why we even do deepwater drilling is beyond me. The President should re-institute the moratorium on offshore drilling.

13 comments to The Deepwater Horizon Disaster

  • Wayne Dawson


    For what it is worth, what I wrote was “back up plans”.  (The plural.)   That is, not just one last ditch effort to shut the whole thing down, but multiple options.  They had nearly a mile of pipe between their “panic button”  (the BOP) and the spigot at the top. 

    Even a typical accelerator facility has more options than that.

    I think one of the things that made Boeing famous was a picture of a B17 held together by a thin piece of skin on the fuselage but still flying (and indeed it made it home).   In engineering, there cannot be enough said about overdesign.  

    Perhaps some higher-up (who was probably paid 20 to 100 times more than the engineers and therefore obviously 20 to 100 times wiser) felt that the pautry wisdom of a thoughtful engineer wasn’t worth a few extra bucks of investment.  

    Various remarks in Ecclesiasties comes to mind.

    by Grace we proceed,

  • Richard Blinne

    Wayne, I was trying to be generous with BP at the time but the more I find out the more shocked I am. Note the following from a recent AP report:

    “In the 52-page exploration plan and environmental impact analysis, BP repeatedly suggested it was unlikely, or virtually impossible, for an accident to occur that would lead to a giant crude oil spill and serious damage to beaches, fish, mammals and fisheries.
    BP’s plan filed with the federal Minerals Management Service for the Deepwater Horizon well, dated February 2009, says repeatedly that it was “unlikely that an accidental surface or subsurface oil spill would occur from the proposed activities.”
    And while the company conceded that a spill would “cause impacts” to beaches, wildlife refuges and wilderness areas, it argued that “due to the distance to shore (48 miles) and the response capabilities that would be implemented, no significant adverse impacts are expected.” 

  • Richard Blinne

    Uh-oh. The Ocean Circulation Group at the University of South Florida is forecasting the oil spill to enter the loop current.
    <a href=”” rel=”nofollow”></a&gt;
    <a href=”” rel=”nofollow”>Giant hypoxic zones</a> are being created under the water. Meanwhile, the Pelican is the only NOAA ship monitoring the use of dispersants under the water (so BP can claim the spill is smaller than it is). The problem is the cold water does not disperse the oil well creating the above-mentioned hypoxic zones. If we learned anything from the Exxon Valdez disaster it was the environmental damage that is caused when oil is in deep, cold, water.
    The Southern Environmental Law Center filed suit yesterday to prohibit offshore drilling exemptions.

    “On May 17, 2010, SELC filed a lawsuit challenging the Minerals Management Service for its complicity in the Gulf oil disaster and its failure to require a thorough examination of spill risks from exploratory drilling operations like British Petroleum’s Deepwater Horizon. Our legal filing seeks to overturn environmental review exemptions MMS has issued for more than 20 exploratory wells since the April explosion that destroyed the BP rig, and it seeks to prohibit the agency from continuing to exempt new exploratory drilling operations in the Gulf from an in-depth environmental analysis, which is required by federal law.

    A Free Pass for Drilling Operations

    According to documents we filed in court, MMS violated the National Environmental Policy Act by exempting BP’s Deepwater Horizon from an environmental review and by giving the same free pass to more than 20 new structures and exploratory wells in the wake of the Gulf disaster. These include four projects at almost twice the depth (over 9,000 feet) of the one currently hemorrhaging oil in the Gulf of Mexico (almost 5,000 feet).  The agency’s continued issuance of these waivers—known as “categorical exclusions”—must be halted in light of the widespread environmental damage caused by the BP spill.  ”

May 2010
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