Posts Tagged ‘blowouts’

Now that the 2021 US OCS incident spreadsheet has been posted and I have commented on the fatalities, I’ll be looking at some incidents by category starting with losses of well control (LWCs). Incident summaries and links to investigation reports follow the bullet points.

  • 4 LWCs incidents in 2021
  • None posed a significant threat to worker safety or the environment
  • All were deepwater wells
  • 3 were during exploratory drilling and 1 was during completion operations
  • All 3 drilling incidents involved water flows after setting 22″ surface casing.
  • The completion LWC was the result of the inadvertent opening of fluid control devices. The report on this incident provides important information for well completion risk assessments.

Incident summaries

Spreadsheet incident 19: Well completion operation. Inadvertent shearing and opening of the fluid loss control devices were not adequately assessed during the planning and review phases of the completion. While displacing the wellbore from 14.8 ZnBr to 14.8 packer fluid, the downhole equivalent circulating density sheared the upper and lower fluid loss control devices. The rig immediately began to experience fluid losses of 600 bph. A 50 bbl fluid loss pill was spotted and losses slowed to 345 bph. A second fluid loss pill was pumped which significantly decreased the losses eventually resulting in zero losses. After losses stopped, the rig experienced approximately a 14 bbl gain on the trip tank. The well was shut in on the annular and circulated out using the driller’s method. Oil was observed in the returns. While waiting on additional fluids and materials, wellhead pressure was managed by bullheading 14.8 brine when required. The well was killed via bullheading down the annulus followed by bullheading down the workstring with 3 CaCo3 pills. investigation report

BOE comment: While the cause of this incident is classified as “human error,” the failure to properly assess and plan for risks associated with the inadvertent shearing and opening of the fluid loss control devices is an organizational/management issue.

Incident 186: Shallow water flow during exploration drilling. Lost well. A shallow water flow was observed from one of the ports in the 38″ wellhead housing following cementation of the 22″ riserless casing string at Caramel Keg (GB 962 #1). Additional wireline logging (casing bond log and temperature log) runs were performed to gain additional insights into the potential source/location of the flow, as well as the quality and presence of cement behind the 22″ casing string. Approval from BSEE Lafayette district was received on April 1st to proceed with running the riser/BOP and continue with subsequent planned operations. Flow from the wellhead was monitored and a general reduction trend in flow from wellhead port was observed. Approval was received from BSEE on April 19th to install and close ball valves on two wellhead ports to isolate flow from wellbore. On April 20th, the ball valves were closed and flow from the wellbore ceased approximately 23 days after initial observation. Approval to temporarily abandon the well was received from BSEE on April 25, along with a monitoring plan of the wellbore and the surrounding area. TA operations concluded on April 27th. The ongoing monitoring program has since identified no indications of flow/broaching at or near the GB 962 #1 wellbore as of May 7th. No personnel were injured or evacuated as a result of this subsurface shallow water flow. report

Comment: The BSEE incident investigation team determined that salt contamination probably caused the cement to go under-balanced triggering flow and channeling behind the 22-in casing.

Incident 478: Exploration well – 7188′ WD; exploration. The 22″ casing cement job went as planned with positive cement returns to the mudline from dye and pH meter. The rig observed post cementing flow. Flow was predominantly gas. The flow started with a single source from the seabed, about 20 ft away from the wellhead. Within the next 2-3 hours, two other flow sources developed, one immediately adjacent to the jetpipe while another flow source surfaced about 10ft away from the wellhead. The rig continued to monitor the post cementing flow and completed multiple ROV wagon wheel surveys. No new seafloor anomalies or active flow points were identified away from the wellhead. Minor flow of water and gas continued at the wellhead. No investigation report.

Incident 507: Post Cement Flow Summary: The 22″ casing was cemented in place at 2:30 AM on August 18, 2021. At approximately 5:45 AM, a minor post cementing flow was observed by the ROV. The flow was only observed from 1 cement port/ball valve connected to the 28″x22″ annulus. The flow composition was predominately cement and absent hydrocarbons. The ROV continued to monitor the flow. No investigation report.

Read Full Post »

Phil Rae piece in Fuel Fix

  1. The well clearly had losses through the shoe during the initial displacement of the heavy spacer with seawater, immediately prior to the negative test.
  2. Allowing for, and accepting, losses of ~80 bbls during spacer displacement, explains ALL pressure and flow anomalies without the need to create or invoke undocumented and unsubstantiated valve closures or manipulations that contradict witness testimony of events. It also eliminates the need to adopt unrealistically-low pump efficiencies for the rig pumps, hypothetical washed-out tubing and ridiculously high viscosities for the drilling mud, in an effort to fit questionable computer models.
  3. Despite extensive examination by investigators and the publication of several reports, the fact that the well experienced losses, making it even more severely underbalanced than was planned, has been given little credence or has received little or no attention, despite several clear indications that this was the case. While this statement regarding losses may be self-evident, its significance on the outcome at Macondo merits closer examination since it explains many previous, apparently-contradictory aspects of the disaster.
  4. Under-displacement of heavyweight spacer, as a result of losses during displacement, caused U-tubing and partial evacuation of the kill line, the lower end of which was later refilled with heavyweight spacer, driven by pressure and flow from the formation. The vacuum, initially, and subsequent invasion of heavy fluid rendered the kill line useless for monitoring the well since the line was effectively blind to pressure changes in the well.
  5. While initial flow into the well was through the shoe, pressure above the casing hanger seal during the negative test was reduced to levels that could have allowed the casing to lift, compromising the seal and possibly also allowing flow from the external annulus.
  6. The well encountered further losses during the second displacement (to displace the riser), after completion of the negative test. These losses, which were perhaps as much as 200 bbls, effectively replaced heavy mud with sea water in the casing below the drill pipe. This further underbalanced the well to the point that it was being kept under control only by pumping friction pressure. As the pump rate was reduced prior to shut down for the sheen test, effectively reducing system backpressure, the now severely underbalanced well began to flow.

Read Full Post »


oil-eating bacteria

Woods Hole Oceanographic Institute scientists have published important new findings on the rapid bacterial degradation of the Macondo spill.

They found that bacterial microbes inside the slick degraded the oil at a rate five times faster than microbes outside the slick—accounting in large part for the disappearance of the slick some three weeks after Deepwater Horizon’s Macondo well was shut off.


Read Full Post »

Dauphin Island tarballs, May 2011

Cheryl’s update after reviewing the latest reports:

  • There is a USCG unified command specific to BP spill residue after storms.
  • The tarballs are not considered toxic, just an unattractive nuisance.
  • Tarball cleanup on Dauphin Island was halted on May 1 to protect nesting birds.
  • BP estimates a total Macondo spill volume of about 4 million bbl as opposed to the government estimate of 4.9 million bbl.
  • BP estimates that 850,000 barrels were captured, burned or skimmed off the water.
  • 1,260 people remain employed in spill cleanup as of [July 14, 2011], down from a peak of 48,200 a year ago

Articles of interest:


WALA New Orleans

Bloomberg Business Week 

Read Full Post »

Very interesting findings for those interested in the fate of spilled oil:

The deep sea entrainment of water-soluble hydrocarbons has far-reaching implications for deep water oil spills. Our results demonstrate that most of the C1-C3 hydrocarbons and a significant fraction of water-soluble aromatic compounds were retained in the deep water column, whereas relatively insoluble petroleum components were predominantly transported to the sea surface or deposited on the seafloor, although the relative proportions are not known.

The resulting apportionments of hydrocarbon transfers to the water column and atmosphere are therefore very different for a deep water oil spill versus a sea-surface oil spill. During seasurface oil spills, highly water-soluble components such as BTEX, C3-benzenes, and naphthalene quickly volatilize and are rapidly lost to the atmosphere within hours to days, thereby limiting the extent of aqueous dissolution into the water column. In the case of the Deepwater Horizon oil spill, however, gas and oil experienced a significant residence time in the water column with no opportunity for the release of volatile species to the atmosphere. Hence, water-soluble petroleum compounds dissolved into the water column to a much greater extent than is typically observed for surface spills.

Read Full Post »

From the West Australian:

A new system to regulate the offshore gas and oil industry – a direct response to the 2009 Montara north of the Kimberley – has been approved by the Federal Parliament’s lower house.

Under the changes, the seven state and territory authorities will be replaced by a single Commonwealth body, the National Offshore Petroleum Safety and Environmental Management Authority.

It will regulate all safety issues from exploration to well decommissioning.

In the US, the jurisdictional conflicts (offshore) differ in that they typically involve multiple Federal regulators with overlapping jurisdiction and different priorities. Since most of the necessary streamlining would only involve Federal agencies, one would think that regulatory reform would be achievable, especially after a major blowout that killed eleven. Unfortunately, meaningful US reform appears to be highly unlikely.

Read Full Post »

I don’t buy the argument that industry and regulators have paid too much attention to personal safety at the expense of process safety. Casualties from falls, falling objects, helicopter crashes, and other workplace activities have been persistent, and safety management programs must emphasize practices and procedures that will reduce occurrence rates.

Also, process safety has hardly been ignored. API RP 14 C has proven to be an effective safety analysis procedure for addressing undesirable events associated with each process component of a production facility.  For more complex facilities, Deepwater Operating Plans and API RP 14J, “Recommended Practice for Design and Hazard Analysis for Offshore Production Facilities, ” are good risk management supplements to RP 14C.

That said, we need better programs for sustaining the focus needed to further reduce the probability of low frequency, high consequence events.  When memories about the most recent disaster start to fade, what do we do to keep workers on edge and prevent complacency? What more can be done to prevent events with enormous consequence potential?  Some thoughts:

  1. Establish programs to remind employees about past disasters – how they happened and how they could have been prevented. How many offshore workers know the chain of events that led to the Santa Barbara blowout, Ocean Ranger sinking, Alexander Kielland capsizing, Piper Alpha fire and explosion, Ixtoc blowout, and other historic incidents? When discussing international incidents, we need to explain how our facilities or region might have been vulnerable under similar circumstances.
  2. Present information on minor incidents that could have escalated into disasters, emphasizing what could have gone wrong and why.
  3. Don’t just focus on the last disaster.  While addressing the operational and organizational issues that surfaced at Montara and Macondo, we also must assess incident data and identify activities and practices that could lead to the next disaster.
  4. Operators should not rely on the regulator to manage their operations. Reading about Montara and Macondo, one senses that the regulators were called on to referee internal company disputes and protect the operators and contractors from themselves.
  5. Regulators should not be making day-to-day operating decisions. Regulators should make sure that the regulations are clear and that operators have effective management procedures for adjusting programs as new information is obtained. Regimes that provide for regulator approval of each activity or adjustment promote operator complacency and are not in the best interest of safety over the long term.
  6. Service companies and contractors must challenge operators and regulators.  Operators should expect contractors to think and question, not to simply execute orders. There are impressive examples of contractors insisting on safety improvements, and being willing to forego business rather than compromise on safety.
  7. All sectors of the offshore industry should participate in standards development. Effective standards are dependent on diverse input.
  8. Industry and government leaders should promote innovation. Obvious weaknesses should be identified and industry should be challenged to propose solutions. For example, why do concerns about “false alarms” preclude automatic alarm activation (see Transocean’s Macondo report)? Data from redundant sensors can be analyzed by predictive software that is capable of quickly identifying real events. Similarly, why have advances in BOPE, including monitoring systems, been so slow? Why are BOP capabilities still poorly understood? Why are well integrity and casing pressure issues (producing wells) so common?

Read Full Post »


Animation of Transocean’s BOP analysis

Transocean’s BOP Defense:

Forensic evidence from independent post-incident testing by Det Norske Veritas (DNV) and evaluation by the Transocean investigation team confirm that the Deepwater Horizon BOP was properly maintained and did operate as designed. However, it was overcome by conditions created by the extreme dynamic flow, the force of which pushed the drill pipe upward, washed or eroded the drill pipe and other rubber and metal elements, and forced the drill pipe to bow within the BOP. This prevented the BOP from completely shearing the drill pipe and sealing the well.

In other words, Transocean contends that properly maintained BOPE was not up to the task of shutting-in and securing a high-rate well. If true, this finding has significant implications for the offshore industry.  I’m looking forward to reading the government’s findings on the BOP failure when the Joint Investigation Team report is issued next month.


Read Full Post »

BP settled Macondo litigation with Weatherford, manufacturer of the float equipment equipment used in the Macondo well. The failure of this equipment was a key contributing factor in the Macondo blowout. Under the agreement, Weatherford will pay BP $75 million.  This money will be applied to the $20 billion Macondo trust fund.

Weatherford is the first of BP’s contractors to formally agree with BP that the entire industry can and should learn from the Deepwater Horizon incident. Accordingly, Weatherford has committed to working with BP to take actions to improve processes and procedures, managerial systems, and safety and best practices in offshore drilling operations. BP and Weatherford will encourage other companies in the drilling industry to join them in this improvement and reform effort.


  1. $75 million seems like a rather modest payment by Weatherford given the magnitude of Macondo damage costs. BP will “indemnify Weatherford for compensatory claims resulting from the accident.”  Presumably, Weatherford’s sales agreements provide good legal protection.
  2. One of the root causes of the Montara blowout was also a float collar failure. That float collar was also supplied by Weatherford.  I’m surprised that this common cause and supplier have received almost no attention. Of course, no one has paid much attention to Montara, either before or after Macondo. Had more attention been paid to the Montara inquiry, Macondo might have been avoided.  (Note that most of the post-Macondo commentary still implies that deep water is the threat even though Montara was in 80 m of water and the root causes of Macondo were not water depth related).
  3. When do we learn more about the “improvement and reform effort” described in the quote above?

Read Full Post »

Resources Minister Martin Ferguson is determined to establish a single national regulator after the Montara oil spill in the Timor Sea leaked oil and gas condensate for more than two months in 2009.

The WA government is at odds with Mr Ferguson over plans for a national regulator and wants to maintain responsibility for oversight of the industry in the state.

Senator Eggleston and Senator David Bushby said the federal government had introduced the legislation to parliament before concluding ongoing negotiations with the WA government. Herald Sun

Meanwhile, still no news regarding any penalties for Montara operator PTTEP.  Will there be none?

Read Full Post »

Older Posts »