Schlumberger

Case Study: Rhino XC 8000 Reamer Enlarges 9,313-ft Interval of Unstable Shale Formation in Single Run

Integrated solution with PowerDrive X6 RSS successfully underreams section with 205 circulating hours to facilitate casing run, Alaska

Challenge: Drill a 9,313-ft interval from 8 3/4 in to 9 7/8 in in one run with minimized shock, vibration, and stick/slip risk in an unstable shale formation, facilitating a 7-in, 26-lbm/ft casing run.

Solution:

  • Deploy an integrated BHA that included the Rhino XC 8000 on-demand hydraulically actuated reamer, PowerDrive X6 rotary steerable system, and SHARC high-abrasion-resistance PDC drill bit.
  • Use @balance Services managed pressure and underbalanced drilling and lowsolids, non-dispersed (LSND) fluids from M-I SWACO, a Schlumberger company.

Result:

  • Underreamed the 9,313-ft interval in one run with full index control for 205 circulating hours.
  • Overcame tight spots along the extended 2,900–12,213-ft-MD interval while running casing.

Efficiently enlarge interval in unstable shale

An operator in Alaska was drilling in a field that included low-pressure sands as well as unstable shales with weak bedding planes and fractures. These conditions posed significant risk to drilling operations, especially running 7-in casing.

The operator wanted to enlarge a 9,313-ft interval from 8 3/4 in to 9 7/8 in in one run while minimizing shock, vibration, and stick/slip risk by maintaining full index control from shoe to shoe.

Use a customized, integrated BHA

Based on these drilling challenges, Schlumberger engineers recommended an integrated solution that included the Rhino XC 8000 hydraulically actuated reamer, PowerDrive X6 RSS, a SHARC bit (MDSi516), and @balance Services drilling.

The Rhino XC reamer eliminates pumpdown activation and can be placed anywhere on the drillstring for increased operational flexibility. Additionally, its reaming mode can be changed in minutes to effectively enlarge boreholes regardless of the well’s inclination angle. This allowed the operator to deactivate multiple times during the run, both above and below critical formation tops, to circulate bottoms-up and to effectively manage equivalent circulating density for a clean wellbore.

The integrated drilling system also included the push-the-bit PowerDrive X6 RSS to minimize the effects of the external drilling environment and several drilling fluids to prevent risks associated with unstable boreholes, uncertain pressure regimes, and narrow pressure windows.

Additionally, to prevent, detect, and mitigate potential well control events while further stabilizing the shales from pressure cycling, Schlumberger suggested @balance Services managed-pressure drilling. This suite of engineering and software tools assess conditions and risks before and during managed-pressure drilling operations to effectively manage the downhole pressure barrier and meet operators’ drilling, economic, and HSE objectives.

Achieved drilling objectives

The operator successfully underreamed the 9,313-ft interval in one run with 205 circulating hours using the PowerDrive X6 RSS and Rhino XC reamer. By successfully managing precise wellbore stability challenges while drilling, the operator also performed a successful casing run and encountered no tight spots along the 2,900–12,213-ft-MD interval.


Download: Rhino XC 8000 Reamer Enlarges 9,313-ft Interval of Unstable Shale Formation in Single Run (0.56 MB PDF)

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Integrated BHA Meets Shale Objectives in Single Run

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Schlumberger recommended an integrated BHA that included the Rhino XC reamer, which eliminates time-consuming pumpdown activation.