Total Eliminates Bit Run with OptiDrill Service in 17 1/2-in Section in North Sea | SLB
Case Study
Location
Offshore
Details

Challenge: Kick off a 17 1/2-in section from a 20-in vertical casing and drill to section TD in one run.

Solution: Use OptiDrill real-time drilling intelligence service to preserve the life of the bit and minimize risk; drill to section TD with PowerDrive X6 RSS and a roller cone bit from Smith Bits, a Schlumberger company.

Results:

  • Drilled large hole section to TD in one run
  • Increased overall ROP
  • Achieved smooth wellbore
Products Used

Total Eliminates Bit Run with OptiDrill Service in 17 1/2-in Section in North Sea

Real-time drilling intelligence service extends bit life by preserving cutting structure

Drill a large-hole section through interbeded formation in one run

Total was drilling an offshore field development well from a semisubmersible rig in the Laggan field of the North Sea. The operator planned to kick off from a 20-in vertical casing and drill a 17 1/2-in section to TD in one run. The wellplan called for a dogleg severity (DLS) of 2º/30 m. Drilling the 17 1/2-in section in offset wells in this field had required two bit runs, and Total expected to encounter interbedded higher-strength formations while drilling this section.

Manage drilling risks with OptiDrill service to extend life of BHA

Schlumberger recommended using the PowerDrive X6 RSS and a roller cone bit, complemented by the OptiDrill real-time drilling intelligence service, to drill the section in one run. Prejob modeling using the IDEAS integrated drillbit design platform helped to define suggested drilling parameters for each type of formation Total was anticipating.

The OptiDrill service would enable the rigsite team to monitor downhole BHA dynamics and quickly adjust drilling parameters to preserve the life of the BHA, decreasing the severity of an event.

Reached section TD in one run while achieving smooth wellbore

Total drilled to section TD in one run, eliminating the second run that is typically required to drill the 17 1/2-in section in offset wells in the field. On-bottom ROP was comparable to that of offset wells, and overall section ROP was significantly better because the second run was eliminated.

The section of the well crossed three faults and was drilled in inclination-hold mode, a feature of the PowerDrive X6 RSS, which resulted in a smooth wellbore. The smoothness was confirmed by real-time bending moment information from the OptiDrill service.

The roller cone bit rotated 802,000 times while drilling the hole section and encountered brief instances of bit bounce, which were detected and mitigated. Average downhole WOB and downhole torque on bit measurements from the OptiDrill service indicated the bit was performing as expected. Postrun observation of the bit confirmed the diagnosis.

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Average bending moment data from the OptiDrill service confirmed the section was smoothly drilled. The interval between the bending moment curves indicated low lateral motion in the BHA in real time.
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Products Used

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