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of the Deepwater Horizon crew was a possible contributing cause of the kick
detection failure.

BP drilling engineer, Mark Hafle, allowed the temporary abandonment
operations on the Deepwater Horizon to proceed even though he told Donald
Vidrine, the Deepwater Horizon well site leader, that “you can’t have pressure on
the drill pipe and zero pressure on the kill line in a [negative] test that is properly
lined up.” Furthermore, Hafle did nothing to investigate or resolve the pressure
differential issue even though he remained in BP’s office until 10:00 p.m. the
evening of April 20 and had access to real‐time well data (which he logged out of
at 5:27:35 p.m.). Hafle’s failure to investigate or resolve the negative test
anomalies noted by Vidrine was a possible contributing cause of the kick
detection failure.

Patrick O’Bryan, vice president of drilling and completions, and David
Sims, drilling and completions operations manager, were both onboard the
Deepwater Horizon during the negative test on April 20. Between the two
managers, they possessed approximately 50 years of drilling experience. Neither
Vidrine nor Robert Kaluza consulted with their managers about the negative
tests, their interpretation, or any other anomalies that occurred on the evening of
April 20. Further, Hafle warned Vidrine that there might have been a problem
with the negative test. The failure of the well site leaders to communicate well‐
related issues with the managers onboard the Deepwater Horizon was a
possible contributing cause of the kick detection failure.

The Panel identified five negative test procedures that BP developed
between April 12 and April 20. In addition, Leo Lindner of MI‐SWACO
developed a negative test, and the rig crew performed a negative test through
the drill pipe. Also, on April 17, Guide sent an email to Sims stating that there
“had been so many last minute changes to the operation that the WSL’s have
finally come to their wits end. The quote is ‘flying by the seat of our pants.’”
BP’s failure to provide complete and final negative test procedures to the rig in
a timely fashion was a possible contributing cause of the kick detection
failure.

A 15 bbls influx in 6,000 feet of water contains approximately four times
the mass of gas of the same influx in 1,500 feet of water. Early recognition of the
warning signals and rapid shut‐in are therefore crucial to well control in deep
water. Taking action quickly minimizes the amount of formation fluid that
enters the wellbore. The rig crew first observed the drill pipe pressure anomalies

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