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XIX. Recommendations

A. Well Recommendations

1. The Agency should consider promulgating regulations that require the
negative pressure testing of wells where the wellbore will be exposed to
negative pressure conditions, such as when the BOP and riser are
disconnected from the wellhead during permanent or temporary
abandonment procedures. All subsea wells will experience a negative
pressure condition when the BOP and riser are disconnected from the
wellhead at either temporary or permanent abandonment time. While
operations are being conducted on a well, the mud weight exerted on the
formation is from the rig to the formation. Prior to unlatching the BOP,
the mud in the riser is displaced with seawater in preparation of the rig to
move off of location. This reduces the effective mud weight on the
formation should a cement plug not set properly. Had the Deepwater
472
Horizon crew interpreted the negative test properly, the blowout may have

been averted.

2. The Agency should consider incorporating in the Code of Federal
Regulation (CFR) parts of API Recommended Practice (RP) 65, parts 1 and
2; The Agency should also consider supplementing the CFR to require
compliance with specific API RP 65 requirements relating to among other
things: a minimum hole diameter of 3.0 inches greater than the casing
outer diameter; rathole mud density greater than cement; and mud
conditioning volume greater than one annular volume. Currently, the
CFR only requires a designated operator to provide a written statement on
how it evaluated the best practices included in API RP 65.
473

3. The Agency should research and consider, with a Notice to Lessees (NTL),
defining the term “safe drilling margin(s)” in 30 CFR § 250.414(c), which
refers to “[p]lanned safe drilling margin between proposed drilling fluid
weights and the estimated pore pressures.” The definition should be
expanded to encompass pore pressure, fracture gradient and mud weight.
This expanded definition would be beneficial to BOEMRE and industry.

472 This requirement was incorporated into the regulations with the interim final rule effective
October 14, 2010.
473 API 65 Part 2 was incorporated into the regulations with the interim final rule effective
December 2010. This recommendation is to incorporate specifics within the regulations.

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