Sedco 711: the regulatory issues

OE Staff
Tuesday, March 1, 2011

In the wake of the July 1988 Piper Alpha disaster in the UK North Sea, the Cullen Report introduced a risk management approach to offshore safety, making the production and maintenance of a risk-based ‘safety case' a legal requirement for every UKCS offshore facility, fixed or mobile. Lord Cullen referred to it as a living document that would be subject to continuous monitoring and updates (OE December 1990).

The safety case has to be prepared by industry and presented to the UK Health & Safety Executive (HSE) for review. This review checks the risk assessment process for completeness, but the HSE does not actually approve the safety case. It seeks to satisfy itself that the risks have been identified and assessed by the operator, and that the risk to life and the operational asset have been kept as low as reasonably possible – the ALARP principle.

The US Presidential Commission referred to this North Sea requirement and recommended that the same obligatory riskbased assessment approach to safety be introduced in the US . But it would be a mistake to assume that the production of the safety case is a panacea for the current ills in the offshore oil and gas industry – far from it.

The UK came close to another major disaster of its own with the Sedco 711 incident, which occurred just a few weeks before Deepwater Horizon's 31 January 2010 arrival at the Macondo location. Near miss or otherwise, this ‘eerily similar' incident was avoidable, just like Macondo.

Bardolino
On 23 December 2009, a major blowout was narrowly averted on Transocean's Sedco 711 semisubmersible when a formation isolation valve (FIV) located in the production liner failed, with the well in an underbalanced state. The rig was working on the Shell-operated Bardolino field, a single subsea well tied back to the Nelson field fixed platform in the Central North Sea.

The rig crew were circulating the well with seawater as part of the well completion and commissioning procedure. The isolation packer and FIV had been successfully pressure tested from above and then ‘successfully inflow tested to confirm the integrity of the mechanical barrier to the reservoir'.

After the ‘successful' tests, the well was being circulated with seawater in preparation for commissioning. During clean-up and mud displacement, the well began to flow. Mud was displaced over the rig floor and gas detected in the shaker room. The circulating pumps were closed down and the lower annular preventer successfully activated. The middle BOP pipe rams were closed and the well came under control.

By any standard this incident ranks as another negative test failure. In this case, the FIV failed when the well became underbalanced. But, unlike Macondo, the BOP did its job, thereby averting a catastrophic blowout. Transocean subsequently suggested to the Presidential Commission that the North Sea incident was irrelevant to Macondo, claiming that the failure involved a different type of barrier.

But the commission would have none of that nonsense, saying:

'Those are largely cosmetic differences. The basic facts of both incidents are the same. Had the [Deepwater Horizon] rig crew been adequately informed of the prior event and trained on its lessons, events at Macondo may have unfolded very differently.'

Shell had reported the incident to the HSE, as it was obliged to do. In a written response to a separate UK Parliamentary Committee on 10 December 2010, the HSE stated the following:

‘As a result of the HSE investigation . . . a letter was sent to Shell regarding their general well integrity responsibilities under regulation 13, Offshore Installations and Wells Regulations 1996.

‘HSE assessed the corrective actions implemented by Shell and Transocean and considered they addressed the shortcomings that led to this incident and have addressed the well control issues that occur when displacing mud out of the well.'

Predictably, neither Shell nor the HSE published any details. Indeed, were it not for the Macondo disaster we might never have discovered the facts surrounding the Sedco 711 incident – and only then after a Parliamentary Committee had dragged them out of another government department. Was the HSE, in apparently making light of the issue and helping to draw a veil of secrecy over it, acting in the public interest here?

Transocean advisories
Submitting a supplementary submission in respect of the Sedco 711 incident to the same UK Parliamentary Committee in December 2010, Transocean said:

‘The HSE was satisfied with the investigation led by Shell and the actions from the investigation report for Shell, Transocean and Schlumberger, and thus did not require a specific change in procedures as a result of the Sedco 711 incident on 23 December 2009.

However, Transocean issued two operations advisories in response to the incident. A Well Operations Group Advisory, dated 5 April 2010 and issued to all Transocean installations, confirmed the Well Control Handbook would be modified to clarify the requirements for monitoring and maintaining at least two barriers when displacing to an underbalanced fluid during completion operations.

‘The second advisory was issued (14 April) to the entire Transocean North Sea fleet and recommended specific follow up actions related to well control preparedness during a completion phase, awareness of well control indicators, and adequate well programs.'

The remainder of this submission is not worth repeating. It did not impress the Presidential Commission, and does not impress me. In fact, the commission noted:

‘Moreover, according to Transocean, neither the PowerPoint nor this advisory ever made it to the Deepwater Horizon crew.' (p124)

A footnote to Transocean's submission stated:

‘Transocean continues to operate its rigs on the UK Continental Shelf with the highest degree of safety and diligence. It is committed to ensuring a safe and reliable work place for its employees and stands willing to assist the [Parliamentary] Committee in its ongoing inquiry.'

In which case, how does it explain the deaths of 11 crew members on the Deepwater Horizon on 21 April 2010? Perhaps Transocean could begin by explaining why its ‘advisories' did not make it to the Deepwater Horizon before the rig and 11 crew members perished.

News blackout
The Sedco 711 incident was not reported in the UK press at the time, as far as I can tell. Indeed, it only seems to have come into the public domain in August 2010 – some eight months after the event – when the US media picked it up, presumably as a result of the ongoing Presidential Commission interviews and activities.

Having noticed the emerging similarities between Bardolino and Macondo, the UK Department of Energy & Climate Change (DECC) set up a Parliamentary Committee to investigate. They requested submissions from the HSE and Transocean, and these became a matter of public record in December 2010 (www.parliament.uk).

Then the furore erupted. It reached the Scottish Parliament, which also attempted to downplay and trivialise the incident during a heated debate.

What seems clear from the foregoing is that someone did a very thorough ‘news management' job over the many months it took for the first details of the Sedco 711 incident to emerge. If that ‘someone' was the UK Health & Safety Executive – or it was complicit with others in doing so – one again has to ask: whose interests was the HSE serving here?

Case for change
The Presidential Commission has established a new benchmark for public expectation and quite probably transformed the global offshore regulatory landscape forever. It is no longer good enough for the HSE to trivialise and secrete recorded events when direct action and reporting is required. A strong, vigorous regulatory regime is required – one that can learn to communicate freely with Parliament, industry and public alike.

Although its starchy submission to the UK Parliamentary Committee hardly inspires confidence in that regard, the HSE can make a start by being open about the Sedco 711 incident and by answering the questions I have put to it (see above).

The Deepwater Horizon created a huge wake when it sank on 22 April 2010. It has washed against the coasts of America and Europe and found its way into their seats of government – the fingers of 11 dead men pointing the way.

Gone, but never forgotten. OE


Ten questions the UK's HSE should answer

1) The Presidential Commission has investigated the Macondo disaster and reported the facts to the public. Will the Health & Safety Executive (HSE) now do the same for Bardolino and publish the results of the Shell investigation?

2) The HSE has stated it was satisfied with the Shell investigation and the ‘corrective measures' it put in place. Will the HSE explain the foregoing in light of the Transocean submission that it ‘did not require a specific change in procedures as a result of the Sedco 711 incident'?

3) Will the HSE publish the details of the ‘corrective measures' proposed by Shell?

4) Why did the HSE not disseminate details of the Sedco 711 incident to other interested parties, for example the industry body Oil & Gas UK?

5) Why did the HSE not notify BP of the Sedco 711 incident?

6) Why did the HSE not notify the Presidential Commission directly of the Sedco 711 incident?

7) What notices have the HSE circulated in respect of negative pressure tests on wells and the use of single barriers in underbalanced wells?

8) Is the HSE satisfied that the Sedco 711 was operating with a valid safety case?
9) How many FIVs have been installed in the UK sector of the North Sea?
10) How many FIV failures have been reported to the HSE?

 

Categories: Europe Regulations Safety & Security

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