Page 43 - test2

BP also identified advantages of using a liner design, including that the
liner hanger would act as second barrier for hydrocarbons in the annulus; the
primary cement job on the liner had a slightly better chance for successful cement
82
lift due to lower ECD; and it would be easier to justify postponing any remedial
83
cement job until after the temporary abandonment procedure was completed.

BP employees evaluated these approaches to designing the production
casing. For example, on April 14, BP Drilling Engineer Brian Morel emailed a
colleague, Richard Miller, about the options. In his email, Morel referred to
Macondo as a “nightmare well which has everyone all over the place.” Miller
responded to Morel’s email, advising Morel that he had updated his calculations
and model, which indicated that both proposals for the production casing design
were “fine.”
84

When early cement modeling results suggested that the long string could
not be cemented reliably, BP’s design team switched to a liner design. However,
on April 13, Morel asked Eric Cunningham, an in‐house BP cementing expert, to
review Halliburton’s cementing recommendations and modeling. Cunningham
determined that certain cement modeling parameters used by Halliburton
should be corrected. The results of the revised modeling caused BP to switch
back to the use of a long string as the primary option for the production casing.

Ultimately, BP chose to install a long string production casing in the
Macondo well instead of using a liner and tieback. A BP “Management of
Change” document stated that this decision was based on the following factors:
the long string provided the “best economic case and well integrity case for
future completions operations;” the recent cement modeling showed that the
long string could be cemented successfully and, while use of a liner “is also an
acceptable option,” doing so would add $7‐10 million to the cost of completing
the well.
85

The Panel found no evidence that the long string production casing design
was a cause of the blowout.

82
Cement lift is increased pump pressure that results when cement that is pumped down the well
begins to flow back upward against gravity.
83 BP‐HZN‐MBI00020910.
84 BP‐HZN‐CEC000021857.
85 BP‐HZN‐MBI00143292. “Management of Change” is BP’s formal process for evaluating and
approving operational decisions.

38