MEETING THE CHALLENGES OF THE HAYNESVILLE Donya Blakney, Drilformance, USA, outlines the impact that meaningful pairing of bit design and cutter geometry can have on drilling performance in over-pressured shale plays such as the Haynesville.
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s the shale market continues to accelerate, so does the need for drilling technology development to keep up so that performance can be optimised and operator costs reduced. Over-pressured shale plays, such as the Haynesville in the US, present a unique challenge. High mud weight and elevated temperatures can wreak havoc on downhole tools, increasing the risk of unplanned trips and non-productive time (NPT). Choosing the proper drill bit and complementary bottomhole assembly (BHA) to address these challenges can provide notable gains in performance. Bit design and ‘fit-for-purpose’ cutter geometry affect bit response. The bit response must be understood in order to identify the appropriate motor configuration and torque output. Meaningful pairing of these two BHA components ensures success.
Drill bit platform
The Badger Drill Bit Platform presents three drill bit options to target specific
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requirements within the application. Design elements include Badger cutters, TruSteer cutters, TruSteer back rakes, a gauge design that enhances lateral stability and hole quality, blade stand-off and a nozzle placement that increases hydraulic efficiency. Operators have used the platform on over 75 runs.
Cutter technology
The Badger cutter is designed for operators drilling over-pressured shales. The cutter’s relieved face geometry is more sensitive to weight on bit, providing better point loading and shearing capability in high mud weight applications. The relieved cutter face reduces the confining pressure of the formation more effectively than a flat face or wedge style cutter. The geometry also reduces friction along the cutter face, changing the cutting’s structure and resulting in faster cuttings evacuation and reduced heat generation at the cutter tip. Lower temperatures
