In a series of Bakken formation multizone completions, a polycrystalline diamond compact (PDC) bit for frac-plug drillout has averaged a 40% increase in plugs drilled with 40% more total drill time, while improving the drilling rate to an average 5.5 min/plug compared with standard mill bits. The SlipStream PDC bit developed by Varel Oil and Gas Drill Bits is designed to overcome drillout challenges presented by the metal, composite, and elastomer components of standard bridge and frac plugs. Building on the SlipStream roller-cone model, the PDC bit exhibits similar improvements in efficiency and wear while providing the inherently greater reliability of a solid-body bit. The PDC design improves efficiency and minimizes torque with shock studs located strategically around the bit shoulder and gauge. The studs limit interaction with the fracturing plug to achieve a more efficient cutting structure with reduced torque. Passive cutter back rake also helps reduce torque generated when cutting. Bit life is enhanced by a longer gauge to enhance stability and durability. The cutting structure is a six-blade, 9-mm PDC design plural set for redundancy, with cutters on different blades located on the same radius from the center.
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Fig. 1—Varel’s SlipStream PDC bit builds on fracturing-plug drillout success of the SlipStream roller-cone model