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well condition data collected by Sperry‐Sun during the temporary abandonment
procedure and reports prepared by the International Association of Drilling
Contractors (“IADC”) to help reconstruct and identify key issues during the 24
hours immediately prior to the blowout. Keystone Engineering conducted a
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casing buoyancy analysis. Oilfield Testing and Consulting conducted a cement
blend analysis on samples provided by Halliburton. Det Norske Veritas
(“DNV”) conducted the forensic examination of the Deepwater Horizon’s BOP
stack and sections of drill pipe and provided a forensic analysis report detailing
the information and conclusions developed based on this examination. These
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expert reports are attached as appendices to this Report.

The purpose of this investigation was to identify the causes of the
Macondo blowout and issue recommendations in order to reduce the likelihood
of a similar event in the future. Throughout this report, the Panel classifies the
factors that contributed to the blowout in the following categories:

 Causes are those factors that most immediately and proximately caused
the blowout; that most directly led to the circumstances underlying the
blowout; or that allowed the blowout to happen. But for these factors,
there would not have been a blowout. These factors may be specific
events or conditions that existed in the well or on the rig at the time of the
blowout.

 Contributing Causes are those factors that alone would not have led to
the blowout, but that were significant in contributing to the events or
conditions that gave rise to the blowout. For a factor to be classified as a
contributing cause of an event, there must be compelling evidence
supporting both the existence of the factor and that it materially
contributed to the occurrence or severity of the event.

 Possible Contributing Causes are those factors that either were minor
contributing causes of the blowout or for which the evidence suggests the
factor’s contributing role in the blowout is weaker or less compelling.

10 The casing buoyancy analysis evaluated whether the production casing floated up the wellbore
a result of the blowout.
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As discussed in more detail later in this report, a BOP stack is a large device that sits on top of a
well and is designed to assist rig crews in maintaining control of the well. Various BOP stack
components can be manually or automatically operated to seal the well and protect against a
blowout. The central issue investigated by the JIT regarding the Deepwater Horizon BOP was why
the BOP failed to stop the flow of hydrocarbons from the Macondo well.

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