Schlumberger

Staged Hole Opener

Achieve high-quality hole opening at an aggressive ROP

The staged hole opener (SHO) incorporates precision-engineered cutting structures to ensure fast, smoothly drilled, high-quality, concentric hole opening under a wide range of application conditions. SHO tools are run successfully on rotary and rotary steerable assemblies in both straight and deviated holes. 

Precision-engineered cutting

While the overall cutting structure is balanced, it is divided into four sections, each serving a specific purpose:

  • Stage one, pilot bit
    Using either a fixed-cutter or roller cone bit, the pilot bit drills the initial hole diameter. A bull nose can also be used to follow a predrilled pilot hole. SHO assemblies can be used with multiple pilot configurations for specific applications and can be positioned for various drillstring configurations. 
  • Stage two, SHO pilot section
    The pilot section consists of one or two rows of cutting structures to recondition the pilot hole and remove any swelling clays or moving halites. Gauge pads provide initial stabilization as the SHO begins the staged reaming process to reduce stick/slip, whirling, or off-center tendencies.
  • Stage three, SHO pilot conditioning section (PCS)
    The cutting structure is designed to minimize work rates on each cutter position for maximum durability. By stress-relieving the formation with this intermediate stage, larger hole drilling can be done at a more aggressive ROP. The third stage recentralizes the SHO on the given well trajectory in both vertical and directional applications.
  • Stage four, SHO reaming section
    This cutting structure completes the final hole diameter. With the formation already stress-relieved, the reaming section remains aggressive, even in more competent formations. Gauge trimmers and spiraled gauge pads ensure good hole quality. Gauge pads in this section are kept short in length for directional responsiveness.

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SHO Specifications

Staged Hole Opener
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