Deepwater Gulf of Mexico operator drills narrow margin in depleted brownfield and elimiates lost circulation, improves wellbore stability, and gains access to proven and conventinally undrillable reserves

• Reservoir sands with depleted pore pressure and fracture gradient
• Wellbore stability requires high static mud weight above 13.4 ppg → High ECD
• Narrow margin between fracture gradient and wellbore stbaility → Lost circulation
• Low fracture gradient needs low static mud weiight and ECD → Wellbore instability
• Conventional drilling unable to drill → 2 sidetrack wells lost

• Get first MMS approval for automated pressure drilling in deepwater
• Close circulation drilling with HOLD 2500
• Reduce static mud weight below level needed for well control
• Manage pressure during connections with Dynamic Annular Pressure Control system
• Perform HAZID / HAZOP and train personnel

Controlled BHP between 13.9 ppg dynamic & 13.7 ppg static
Maintained a 0.3 ppg margin of safety in the high risk lost circulation zone
Reduced mud cost and increased drill rate - drilling had to be controlled at 200 fph
Drilled planned TD and ran production liner with no lost circulation or hole instability
Reached previously unreachable reserves