Spear

Shale-optimized steel-body PDC drill bit

Spear PDC drill bits have been specifically designed to improve the economics of shale plays by efficiently drilling a curve and a long lateral hole section, minimizing bit balling and short runs, improving ROP, and enhancing directional control.

Conventional PDC bit designs target either the curve or the lateral section, but not both. Moreover, lack of hydraulic energy at the drill bit means that cuttings accumulate at the bottom of the well, impeding access to fresh rock and dramatically reducing ROP. Packed blades, plugged nozzles, and drillstring stick/slip are other consequences. The shale-optimized steel-body drill bits provide a solution to all these challenges.

Efficient cuttings removal

Spear drill bits minimize buildup of cuttings in front of the bit and improve ROP with the following engineered features:

• Directional mud flow–cleans debris so that a sharp cutter edge always meets rock, maximizing ROP.
• Bullet-shaped body–streamlines the bit, making it easier for cuttings to sweep around the body and into the junk slot.
• Reduced body diameter–increases the distance between the borehole and the bit body in the junk slot, improving the ability of cuttings to pass through the slots. Greater area around the body allows the bit to pass over or through a cuttings bed, without blade packing and nozzle plugging.
• Greater blade height–increases the junk slot area.

Enhanced directional control and ROP

To improve directional control, Spear drill bits use smaller—11 mm and 13 mm —cutters, with no adverse effect on ROP. Large cutters have a substantial depth of cut that creates a higher instantaneous torque response and can cause the loss of toolface control.

The bits can be fitted with ONYX II PDC cutters that are more thermally stable, as well as more wear- and impact-resistant than other PDC cutters, both standard and premium. ONYX II cutters remain sharp longer, translating into more footage drilled at maximum ROP and substantially reduced drilling costs over a wide range of applications.

Improved stability and dogleg capability

Lo-Vibe depth of cut control inserts minimize BHA vibration that can cause numerous drilling problems and result in significant NPT.

In the targeted applications, directional drillers use a steerable motor with a bent housing to steer the bit and achieve the desired dogleg severity (DLS). A longer bit-to-bend length puts excessive torque on the motor and bit. The smaller makeup length of a Spear bit is an inherent advantage. Moreover, the bits can be run on a motor with a lower bend angle, allowing rotation and a high ROP in the lateral, while still achieving the desired build rates in the curve section.

IDEAS-certified design 

IDEAS integrated drillbit design platform is used to optimize the cutting structure design for bit dynamics and formation lithology. The design takes into account every element of the BHA, resulting in superior, application-specific bits and reduced drilling risk.

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