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wellbore circulation because it was concerned about additional lost returns that
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could result from a complete bottoms‐up circulation.

On April 19, Halliburton pumped the following fluids down the wellbore:
base oil, spacer fluid, unfoamed lead cement, foamed (or nitrified) cement that
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would go in the annulus, tail cement and additional spacer. After pumping
these fluids, Halliburton pumped mud down the well to move the cement into
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place. After about three and a half hours, the cement crew completed
displacement, and both plugs landed, or were “bumped,” with an estimated 100
psi of lift pressure (350 psi circulating to 450 psi) before bumping the top cement
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plug. The crew conducting the cement job believed they had received full
returns throughout the job, meaning that the crew believed that little or no mud
had been lost into the formation during the cement job. Brian Morel, who was
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usually based in Houston, had been on the rig during the cement job and sent an
email before he left the rig, saying that “… the cement job went well. Pressures
stayed low, but we had full returns the entire job, saw 80 psi lift pressure and
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landed out right on the calculated volume.”

1. Float Check

After finishing the cement job, the cementing crew conducted a float check
intended to confirm that the float valves had properly closed and, therefore,
would prevent any flow back up the well. Vincent Tabler, the Halliburton crew
cementer and Lee Lambert, a BP well site leader trainee, stood at the cement unit
(a vessel on the rig that injects cement into the well) to verify that the checks
were holding. They allowed mud to “flow back until it was probably what we
call a pencil stream, and then it quit for a little while, and then when the rig
would heave, it would give another little pencil stream,” Tabler said, “I know it
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was a good 15, 20 minutes that we watched it.” At the conclusion of the float
check, the crew concluded that the float valves were holding. The cementing
crew completed this job approximately two hours after the cement placement.

129 Guide testimony, July 22, 2010, at 150‐151.
130 See Halliburton post‐job nitrified cementing report and job log (Appendix F).
131 BP‐HZN‐MBI‐00137365.
132 “Bumping the cement plugs,” refers to the process by which the rig crew tests whether the
cement plugs are in the proper place. The crew pumps fluid and looks for a pressure spike that
indicates that the cement plug has “landed” in place.
133 Nathaniel Chaisson email to Jesse Gagliano, April 20, 2010.
134 BP‐HZN‐MBI00129052.
135 Tabler testimony at 22.

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