Upper THDTM Package Latched Onto 20 in. Wellhead

1
Mud Circulating System Top Hole Dual Gradient
S/W Supply Mud Return Lines

• Stabilizes hole to
• Improve core quality
• Run longer total length of OH core
• Improve success with logging
• Mud returns to rig for cutting analysis
• Minimal environmental impact
• Eliminate pump and dump onto seafloor
• Risk mitigation
• - Shallow hazard control
• - Equipment reliability
• Allows drilling to maximum possible depth with
  annular control at all times
• Enhanced safety benefits

Upper THDTM Package Latched Onto 20 in. Wellhead
2
Static Wellbore Pressures
FLOATER
SEA WATER POWER FLUID
MUD HYDROSTATIC PRESSURE THDG
MUD HYDROSTATIC PRESSURE Conventional
MUD RETURN RISER
THDG
DEPTH
DRILL PIPE
SEA WATER HYDROSTATIC PRESSURE
BIT
PRESSURE
TOP HOLE DUAL GRADIENT DRILLING SYSTEM
3
THDGVirtual Riser System
4
Top Hole Drilling Package Options

• Option 1. Deploy Mud Lift pump (MLP) and connect
  to wellhead connector--analogous to drilling open
  hole sections prior to setting surface conductor.
• Option 2. Subsea shutoff device (SSOD), which
  affords some level of well control and shut-in in
  an emergency.

5
Option 1

• THD package connected directly to wellhead
  profile
• Estimated Wt 143,000 lb
• Max WD 10,000 ft
• Run on dual casing risers
• Circulation rate 300-900 gpm
• Mud Weight 12.5 ppg
• Single THD Pod
• Subsea dump line on THD package (annulus suction
  side discharge)
• Surface umbilical reel (11 x 9 x 11 40,000
  lbs.)
• Surface high voltage transformer (7 x 3 x 4
  7100 lbs.)

6
Option 2

• THD package connected to subsea shutoff device
  (SSOD), which is then connected to wellhead
• Estimated Weight s
• THD Pacakage 143,000 lb.
• SSOD 240,000 lbs.
• Total 383,000 lbs.
• Max WD 10,000 ft
• Hydraulic connector between THD package and SSOD
  
• Run on dual casing risers
• Circulation rate 300-900 gpm
• Mud Weight 12.5 ppg
• Single THD Pod Reel
• 52 accumulator bottles--emergency disconnect and
  reconnect sequence
• Integrated THD SSOD controls
• Single control pod reel

7
THDTM Package Layout

• 14 7 x 13 8 x 15 5 (L x W x H)
• 143,000 lbs (est.)