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Technical Paper: Industry’s First Hydro-Mechanical Surface Controlled System for Multiple Reamer Activation/Deactivation Increases Drilling Efficiency

Society: IADC
Paper Number: 163537
Presentation Date: 2013
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Abstract

Using a concentric underreamer is a widely used technique for efficient  wellbore construction. Most underreamers are fitted with lock-out systems to provide a means of drilling out the shoe-track with the cutters closed before enlarging the tool below casing. Several underreamers also provide a system to lock the tool closed after reaching TD to enable full flow while POOH for best possible cleaning. However, a major limitation these systems have in common is the underreamer cannot be reactivated once closed and the tool must be placed at top BHA due to the activation method.

To increase reamer efficiency/BHA flexibility, a new hydro-mechanical system has been developed that makes it possible to perform multiple activation/deactivation of the underreamer by manipulating the flow rate in a short sequence allowing infinite open/close cycling for selective underreaming and more flexible placement opportunities within the BHA. The concept does not require any form of device to be pumped down the drill string. The system also increases the potential to save rig time on the activation/deactivation sequence.

Through the field testing stage, it has been proven that the system works as designed under difficult drilling conditions. It delivers operator value by having the flexibility to selectively activate/deactivate and save rig time. The majority of runs have been on complex rotary steerable BHAs together with MWD/LWD systems and does not interfere with those tools’ operating range. All criteria set in the comprehensive field testing plan have been met to qualify the reamer as a viable downhole tool system.

Several case studies will be presented to document successful operation of the on-demand surface controlled system with details about operator benefits including downhole flexibility, cost savings and increased safety.

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