Gavels In the Gulf: The BP Trial - Week 7 In Review

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Derek Park

BP On the Stand

Week 7 saw BP field a string of witnesses; outside experts as well as its own people. We visited many if the topics from previous week and saw BP having to defend its corporate management practices, despite its attempts to confine the trial scope to the operational activities around the well.

Drilling and Well Construction

BP’s first witness was a well-respected expert in petroleum engineering, drilling operations, well monitoring and well control. He believes that the Deepwater Horizon was a ‘top of the line rig with a top of the line crew’. The well was drilled safely and consistent with industry standard. However the temporary abandonment phase was not consistent with that standard; had it been the well would not have blown out.

The major contention is with earlier testimony from an expert on behalf of the US government who said that BP was outside the safe drilling margin on the final section of the well. BP disagrees that safe drilling margin is defined in reference to the weakest zone in the open hole. They claim it relates to the shoe test or formation integrity test done when drilling out of the shoe into the new section.

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The US witness had also said that shoe test itself was invalid because it was too good to be true and had suggested that the leak off had been measured whilst still within the casing or cement. This led to a belief that the formation was stronger than it really was. BP contested this and also the earlier testimony that drilling of the final interval made the well unstable and dangerous.

They cited MWD technology which allowed the drillers to be fully aware of the changing conditions and to make appropriate adjustments to mud weight as they drilled. The witness said ‘the well was talking to them and they were listening’.

The government lawyers insisted that safe drilling margin is the difference between mud weight and weakest fracture gradient. MMS depositions to the trial showed that BP had drilled the last section with much less than 0.5 ppg margin required by regulation, and they had also failed to notify the MMS accordingly. It is worth remembering that subsequent to the blowout, MMS issued an Incident of Non-Compliance notice (INC) to BP regarding the drilling of this interval.

Other experts included a witness from Weatherford who had managed the team that designed the float collar. He confirmed that Weatherford had run tests on identical equipment which demonstrated that the float collar had converted and that the flapper valves would have held. He dismissed the theory that the ball had somehow extruded from the bottom of the auto-fill tube whilst the tube itself remained in place.

On cross examination Halliburton pointed out that these tests had not considered the possibility of debris inside the float collar which could have jammed the tube. They also raised an interesting question which the judge didn’t allow (but I will!). ‘If the float collar converted, how come 1400psi was seen on the drill pipe during the negative pressure test?’

BP also fielded an expert on casing design. Both the long string and liner casing designs were good, well within industry and BP standards. The long string offered advantages regarding the control of annulus pressure and has less components to fail, so on balance it was a good option.

Temporary Abandonment

BP accepted that the negative test had been a failure and that they bought into it, not because they were reckless but because they genuinely believed there was an explanation. Lawyers for the plaintiffs pointed out that a successful test has no flow and no pressure and ‘a moron would have spotted it’. They said that BP had allowed the well displacement to proceed and did so knowing that the negative test was a failure. A Transocean lawyer pointed out that whilst everyone had ‘stop work’ authority only BP had ‘go forward’ authority.

One of the BP witnesses was a trainee Well Site Leader who had been a ‘fly on the wall’ at key meetings and discussions on the rig. He maintained that the cement job went to plan with no apparent concerns about the float collar. There was no confusion about the temporary abandonment procedure but there was much discussion about the results of the negative test. He saw the drill pipe bled off and the pressure return to a steady 1400 psi. The Transocean driller had put forward the theory that pressure on the drill pipe was the result of heavy mud in the riser somehow transmitting pressure across the closed annular element in the BOP; the so called ‘bladder effect’. The well site leaders seemed happy to accept this explanation.

BP onshore engineers had been aware that initially the negative test had failed but subsequently accepted assurances from offshore that the problem had been solved.


BP conceded that if it had not proceeded to displace the well at that stage then blowout and explosion would not have happened. But if others had caught the kick, or if the BOP had worked or if the flow had been quickly diverted then the situation would not have escalated either. Continual monitoring and control of the well is not the responsibility of the company man; he hires competent contractors to do that.

The line-up of the diverter was again raised by Transocean. It was a BP principle to routinely line up to the mud gas separator to minimise the environmental risk, but surely it should have been lined up overboard prior a critical activity such as displacement? The evidence suggests that the drill crew did manage to get the flow diverted overboard but it was too little too late.

Flow Modelling

BP produced an expert witness in flow modelling who had run the simulations for the BP internal investigation. Taking all the data he had modelled the flows and timings from mid-afternoon until the real time data stopped just before 10pm on the night of the disaster. The pressure on the drill pipe was seen as the key parameter and the simulated case was able to match the records perfectly.

The bottom-hole conditions were however only simulated in terms of ‘net pay zone exposed’. The model was accurate if around one fifth of the interval was assumed to open. There was no detail of what this represented in reality; it could have been a partial cement job and a clean flow path through the shoe track, or less cement and some blockage further up the well (or anything in between!)

The only way the model could replicate the recorded conditions of the blowout were if the flow path was inside the casing. It was impossible to replicate the data using any other scenario such as flow via the annulus to the surface or a breach at the 9"/7" casing crossover. One exception to this however, was Halliburton’s theory that there was a failure in the integrity of the casing below the float collar. He conceded that this could possibly be modelled to fit the data.

Safety Management System

The GoM performance unit leader from 2007-09 was another BP witness. He detailed BP’s full commitment to safety and refuted that the organisation was driven by an ‘every dollar counts’ culture.

BP’s new Operational Management System (OMS) had been implemented as soon as he took over, a demonstration that safety was a key enabler of the business. This process had started in 2008 with a detailed gap analysis leading to a program of improvements. The production areas had been the first to change to the new systems with the drilling areas staring to implement OMS in 2009. The plaintiffs tried to exploit the time delays between identification of problems and implementation of solutions; this was ‘all analysis and no action’.

He said it was true that between 2008 and 2009 production was up and costs were down, but this was the result of new production coming on stream and some extraordinary expenditure on refurbishment coming to an end. It had nothing to do with operations on ‘Deepwater Horizon’. The ‘every dollar counts’ programme was a justifiable focus on not wasting money, within the boundary of safety always being the number one priority.

The plaintiffs raised the question of why BP’s internal investigation had not looked at how its management systems had failed to prevent the incident. BP claims that this was not causal to the blow out but I am sure the court will be looking closely at the evidence. Next week will see evidence from the well team leader onshore amongst managers closer to the front line; I am sure there will be rigorous cross examination

Batteries and Solenoids

BP called their own expert witness to testify whether the AMF/deadman function of the BOP worked on the night of the disaster. You may recall the Transocean story that, despite a flat battery on one control pod and a mis-wired solenoid on the other, the AMF did fire on the night but the pipe was not cut because it was off-centre in the rams.

We have heard hours of testimony on battery and solenoid testing during the trial. The judge even rebuked a lawyer for falling asleep during this latest evidence!

Suffice to say that this expert testified that there was no way the BOP could have functioned given the faults in the control systems and so he agrees with all the other experts except Transocean’s. They are on their own here I am afraid.

Next week sees more from BP and perhaps we can glimpse the light at the end of the tunnel! More to come meanwhile!


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