Subsea Drive Deepwater Value

Casing drilling value: mitigate shallow hazards

• Smearing effect and narrow annulus

• Higher circulating friction increases bottomhole pressure (Conventional vs. Casing Drilling Geometries)

• Wellbore strengthens by plastering drilling cuttings into the formation

• Casing depths based on prevailing pore-pressure / fracture gradients

Deepen the structural casing

• Rapid growth of shallow fracture gradient allows deeper casing shoe for higher formation strength with higher mud densities to mitigate hazards

• Less casing strings in the riserless section allow larger casing strings deeper

• Mitigates loss/kick cycle

• Reduces use of contingency casing strings

Larger drilling operating windows in the lower well sections

• Reduced total well time — fewer hole sections and casing strings, with a single trip to drill the hole section and run casing

• Decrease circulating friction, minimizing fluid-loss/kick cycle

• Create opportunity for contingency casing strings

• Larger hole section across well objectives

• Larger completion

• Increased production rates and improved economics