Government releases DNV's findings on Deepwater Horizon BOP

 (Story updated Mar. 24 with Transocean statement, see 4th paragraph)

Paula Dittrick
OGJ Senior Staff Writer

HOUSTON, Mar. 23 -- Federal officials have released a two-volume report from Det Norske Veritas (DNV) on the forensic examination of the Deepwater Horizon blowout preventer (BOP), and the report recommends additional study be done on the BOP’s failure to close and seal the Macondo well.

On Apr. 20, 2010, a blowout of the Macondo well in about 5,000 ft of water off Louisiana resulted in explosions and fires killing 11 crew members on Transocean Ltd.’s Deepwater Horizon semisubmersible drilling rig. BP PLC operated the Macondo well. A massive oil spill resulted in the Gulf of Mexico.

The Bureau of Ocean Energy Management, Regulation and Enforcement/US Coast Guard Joint Investigation Team released DNV’s report on the BOP, which concluded that off-centered drill pipe prevented the blind shear rams (BSR) from fully closing and sealing the wellbore.

Transocean issued a statement saying, “The findings confirm that the BOP was in proper operating condition and functioned as designed. These results are consistent with the function and pressure tests conducted on the BOP in the days preceding the Macondo well blowout. High-pressure flow from the well created conditions that exceeded the scope of BOP’s design parameters.”

While releasing the report, BOEMRE announced a seventh session of public hearings starting Apr. 4 in New Orleans. The hearings will focus specifically on the BOP forensic examination.

The forensic examination is one aspect of an investigation into the accident and subsequent oil spill. The full investigation report is not expected to be released until sometime this summer, BOEMRE said.

Forensic testing
The report said forces from the flow of the well induced the drill pipe to buckle between the upper annular and the upper variable bore rams (VBR). The drill pipe deflected until it contacted the wellbore just above the BSR.

“This condition would have most likely occurred from the moment the well began flowing and would have remained until either the end conditions changed (change in upper annular or upper VBR state) or the deflected drill pipe was physically altered (sheared), the report said. “The portion of the drill pipe located between the shearing blade surfaces of the BSRs was off center and held in this position by buckling forces.”

Drill pipe became trapped between the ram block faces, preventing the blocks from fully closing and sealing.

“This position of the drill pipe between the upper annular and the upper VBRs led to buckling and bowing of the drill pipe within the wellbore,” the report said.

The BOP examination was completed after the BOP stack was raised from the sea floor on Sept. 4 and transferred to the NASA-Michoud complex in New Orleans. The blind shear, casing shear, and three sets of VBR were removed from the lower section of the BOP and examined both visually and using laser profilometry.

DNV examined the wellbore using high-definition video cameras and used laser profilometry to examine the wellbore and the BSR. The upper and lower annulars in the lower marine riser packer were examined using a high-definition video camera.

Eight segments of drill pipe were recovered, examined, and tested. Two drill pipe segments were recovered from the BOP at Michoud. Three additional segments were recovered from the drilling riser at Michoud. Investigators also examined three other segments of drill pipe that had been previously recovered.

Function testing of the AMF/Deadman autoshear indicated the voltage of the 27-v battery in the blue pod was insufficient to activate the higher-pressure BSR pilot solenoid mounted on the blue pod. Tests of the yellow pod BSR pilot solenoid circuits were inconsistent, the report said.

Recommendations
DNV recommends that industry examine and study potential conditions that could arise in the event of the loss of well control. It suggests numerous studies including:

• Effects of the flow of the well fluids on BOP components and various tubulars that might be present.

• Effects that could arise from the tubulars being fixed or constrained within the components of a BOP.

• Ability of the BOP components to complete their intended design or function under these conditions.

DNV also recommended industry study the ability of shear rams to completely cut tubular and seal the well regardless of the tubulars position within the wellbore.

“The findings of these studies should be considered and addressed in the design of future BOPs and the need for modifying current BOPs to address these findings,” the report said.

DNV also recommended industry examine and study the potential effects or results that closing of the annulars or closing of the VBRs could have on the BOP stack, including an evaluation of how elastic buckling of tubulars could adversely affect the ability to regain control of the well.

Contact Paula Dittrick at paulad@ogjonline.com.

Related Articles

US Forest Service takes no stance on fracturing in national forest

12/12/2014

The US Forest Service has dropped a proposal that would have banned hydraulic fracturing in the George Washington National Forest.

Frac ban exemption made in Broomfield

12/12/2014 A Colorado District Court judge has ruled that a hydraulic fracturing ban in Broomfield, Colo., does not apply to an operator that entered into an ...

OSHA seeks to limit silica exposure for oil workers, Proposed rules target frac sand mining, fracturing

12/12/2014 The rapid growth in oil and gas production from shale and tight oil formations in the US is generating a boom in a related industry: frac sand. San...

Study links methane contamination in water wells to poor well construction-not fracing-in Marcellus

12/12/2014 A new study found that fugitive gas contamination at eight clusters of water wells in the Marcellus and Barnett shale regions might be linked to we...

Weak crude prices could threaten Bakken production growth

12/12/2014 Bakken shale production set another record in August, but weakening crude prices and flaring reduction efforts threatened to temper production grow...

Husky reports start of steam operations at Sunrise oil sands project

12/12/2014

Husky Energy, Calgary, reported the start of steam operations at the in situ Sunrise Oil Sands Project in northeastern Alberta.

TAEP: TPI still peaking, but ‘contraction unavoidable’ as oil prices fall

12/12/2014 The Texas Petro Index (TPI), a composite index based on a comprehensive group of upstream economic indicators released by the Texas Alliance of Ene...

US needs more data before ending crude export ban, House panel told

12/11/2014 Much more environmental impact information is needed before the US can reasonably remove crude oil export limits, a witness told a House Energy and...

BOEM raises offshore oil spill liability limit to $134 million

12/11/2014 The US Bureau of Ocean Energy Management increased the liability limit for oil-spill related damages from offshore operations to $134 million from ...

White Papers

AVEVA NET Accesses and Manages the Digital Asset

Global demand for new process plants, power plants and infrastructure is increasing steadily with the ...
Sponsored by

AVEVA’s Approach for the Digital Asset

To meet the requirements for leaner project execution and more efficient operations while transferring...
Sponsored by

Diversification - the technology aspects

In tough times, businesses seek to diversify into adjacent markets or to apply their skills and resour...
Sponsored by

Engineering & Design for Lean Construction

Modern marketing rhetoric claims that, in order to cut out expensive costs and reduce risks during the...
Sponsored by

Object Lessons - Why control of engineering design at the object level is essential for efficient project execution

Whatever the task, there is usually only one way to do it right and many more to do it wrong. In the c...
Sponsored by

Plant Design for Lean Construction - at your fingertips

One area which can provide improvements to the adoption of Lean principles is the application of mobil...
Sponsored by

How to Keep Your Mud System Vibrator Hose from Getting Hammered to Death

To prevent the vibrating hoses on your oilfield mud circulation systems from failing, you must examine...
Sponsored by

Duty of Care

Good corporate social responsibility means implementing effective workplace health and safety measures...
Sponsored by

Available Webcasts


On Demand

Optimizing your asset management practices to mitigate the effects of a down market

Thu, Dec 11, 2014

The oil and gas market is in constant flux, and as the price of BOE (Barrel of Oil Equivalent) goes down it is increasingly important to optimize your asset management strategy to stay afloat.  Attend this webinar to learn how developing a solid asset management plan can help your company mitigate costs in any market.

register:WEBCAST


Parylene Conformal Coatings for the Oil & Gas Industry

Thu, Nov 20, 2014

In this concise 30-minute webinar, participants have an opportunity to learn more about how Parylene coatings are applied, their features, and the value they add to devices and components.

register:WEBCAST


Utilizing Predictive Analytics to Optimize Productivity in Oil & Gas Operations

Tue, Nov 18, 2014

Join IBM on Tuesday, November 18 @ 1pm CST to explore how Predictive Analytics can help your organization maximize productivity, operational performance & associated processes to drive enterprise wide productivity and profitability.

register:WEBCAST


US HYDROCARBON EXPORTS Part 3 — LNG

Fri, Nov 14, 2014

US LNG Exports, the third in a trilogy of webcasts focusing on the broad topic of US Hydrocarbon Exports.

A discussion of the problems and potential for the export of US-produced liquefied natural gas.

These and other topics will be discussed, with the latest thoughts on U.S. LNG export policy.

register:WEBCAST


Careers at TOTAL

Careers at TOTAL - Videos

More than 600 job openings are now online, watch videos and learn more!

 

Click Here to Watch

Other Oil & Gas Industry Jobs

Search More Job Listings >>
Stay Connected