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hanger and seal assembly remained properly seated in the 18‐3/4 inch high
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pressure housing, where it had been placed on April 19 prior to the blowout.

Additional evidence from the intervention operations also tends to
eliminate this first well flow scenario. On September 10, during the well
intervention operation, BP conducted a positive pressure test of the 9‐7/8 inch
production casing in the Macondo well by pumping 6 bbls of 13.2 ppg drilling
mud down the BOP kill line and reached an instantaneous shut‐in casing
pressure (ISICP) of 4,270 psi. The kill line was then shut in and, after 30 minutes,
the shut‐in pressure remained at 4,158 psi, therefore revealing no flow through
the annulus.

On September 11, following installation of the lock‐down sleeve, BP
successfully pressure tested the lock‐down sleeve seal to 5,200 psi, which
indicated that the well hanger was properly seated because otherwise, annular
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flow would have lifted the hanger.

On September 22, Schlumberger used an isolation scanner tool to log the
characteristics of fluid in the annulus between the mud line and 9,318 feet
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measured depth. This log evaluated, among other things, whether the fluid in
the annulus included “free gas.” Based on the logging data, Schlumberger
determined that free gas was not present in the annulus below the BOP. The
absence of free gas in the annulus provides strong evidence that hydrocarbons
were not present in the annulus during the blowout.

On October 7, the intervention team perforated the 9‐7/8 inch production
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casing between 9,176 feet and 9,186 feet to monitor pressure and returns. The
drilling mud in the interior of the casing at the time was approximately 14.3 ppg
synthetic‐based mud (“SBM”). Hydrocarbons, if present in the annulus, would
have exhibited a much lower density. When fluids of different densities meet at
an opening, gravity and the “u‐tube” effect typically cause the more dense fluid

154 DDII IADC Report, 9/11/10 (TRN‐USCG_MMS‐00043342).
155 DDII IADC Report, 9/11/10 (TRN‐USCG_MMS‐00043342). A “well hanger” is a long string of
production casing that hangs from a casing hanger inside the wellhead.
156 DDII IADC Report 9/22/10 ‐ TRN‐USCG_MMS‐00043388. An isolation scanner tool is used to
evaluate a cement job by taking measurements to help distinguish solids from liquids in the
wellbore. The tool can identify potential channeling and can evaluate whether a cement job has
achieved zonal isolation.
157 DDII IADC Report 10/7/10 (TRN‐USCG_MMS‐00043449). This was done using a perforating
gun and well testing equipment.

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