.pdf asset-performance field_planning_color fit_for_purpose_color production_optimization_recovery_color kpi-box kpi-money kpi-time ::before

A challenging deepwater application required enlarging a 12¼-in. pilot hole to 14½ in. through hard and abrasive interbedded sands, and the customer needed to complete the job without sacrificing penetration rates or drilling performance. They also needed to drill and ream the section to total depth (TD) in a single run—eliminating the rathole without having to trip out for a second hole-opening assembly.

After analyzing offset well data, it was evident that conventional under-reamers using standard polycrystalline diamond compact cutters couldn’t complete this application in one run. This is because traditional reamers/cutting structures often cannot withstand abrasive, highly interbedded formations, resulting in the need for complex bottom hole assemblies and multiple runs.

A customized hole-opening solution

To perform the operation in a single run, Baker Hughes, a GE company (BHGE) suggested deploying two under-reamers— a GaugePro™ XPR reamer and a GaugePro Echo™on-command digital reamer—and outfitting them with reinforced Stabilis™ cutters. The tough cutters would help to improve durability in the challenging formation, and because the GaugePro Echo reamer can be placed near the bit, it would eliminate the need for a dedicated rathole trip. To streamline operational efficiency and performance, a manual with detailed application-specific recommendations, procedures, and operating parameters was made available to key rig personnel.

Download the PDF to read the full case study.

Challenges & Results


  • Drilling a 12¼-in. pilot hole to TD and opening it up to 14½ in. without tripping
  • Maintaining optimal cutter performance in shale and abrasive sands
  • Maintaining optimal cutter performance in shale and abrasive sands


  • Drilled and reamed a difficult 4,807-ft section in a single, 171-hour run
  • Avoided additional trips due to premature cutter wear (1-1 dull grade on the cutters)
  • Eliminated 180 ft of rathole
  • Saved more than 20 hours of trip time
  • Delivered an average ROP of 28.1 ft/hr