The Hadrian-5 prospect in the United States (US) Gulf of Mexico’s Keathley Canyon 919 block was drilled by the operator in ~7000-ft water depth as one of the first Gulf of Mexico wells drilled after the deepwater moratorium. This exploration well was permitted under the new regulatory requirements of the US Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE). These new requirements included additional blowout preventer (BOP) certification and testing, incorporation of selected API recommended practices, and certification of the well design by a registered professional engineer.

In addition to the well design regulations, BOEMRE required operators to calculate a worst-case discharge scenario and develop plans to contain that scenario. Well containment plans were developed that included the newly-formed Marine Well Containment Company’s (MWCC) response capabilities.

The well was drilled between March and August of 2011 to a total depth (TD) of 19,631 ft and encountered several hydrocarbon intervals that were safely managed. The rig selected for this well was the dynamically-positioned (DP), Maersk Developer semisubmersible.

This paper describes the planning, permitting, and execution of this challenging well. Topics covered include:

  • New permitting requirements for federal waters in the US

  • Worst-case discharge scenario and impact on casing design

  • Elimination of trapped annular pressure via well design

  • Minimizing vibrations in the tuff formation of the Hadrian mini-basin

  • Managing the uncertainties associated with sub-salt formation pore pressures

  • Drilling and casing mobile tar zones

The well was drilled and evaluated in a safe manner with no significant incidents even though the geologic formations encountered were different than predicted.

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