Deepening first string provides stronger casing shoe strength due to the rapidly increasing fracture gradients at shallow depths

Deepwater Riserless Casing Seat Optimization improves deepwater well reliability, creating larger hole diameters below the high-pressure wellhead conductor (HPWH)

The larger hole / casing annuli results in ECD reduction to drill the narrow operating pressure windows while navigating the ballooning cycle

Basis of Design:

  • First casing setting depth on prevailing pore / fracture pressures, that is structural casing

  • Drill to planned depth, replacing jetting & mitigating shallow geohazards

  • Drill next riserless section conventionally using “pump & dump”, or

  • Set HPWH with high-pressure conductor deeper than conventional practice

U.S. Patent No. 8,229,671 B2 July 24, 2012, Method and System for Riserless Casing Seat Optimization