Last year, Baker Hughes introduced the next generation in polycrystalline diamond compact (PDC) bit design — re-engineered to deliver unmatched rate of penetration (ROP) and durability in a wide range of applications. The Quantec Force line of bits provides a cost-effective alternative to highly durable, but much slower, impregnated drill bits.

“Our technology developments are focused on reducing drilling costs for operators,” says Mark Freeman, diamond product manager for Baker Hughes. “With this new bit design, operators no longer are forced to sacrifice durability for high rate of penetration and vice versa. We see this as a definite game-changer in PDC bit technology.”

The new bit design is proving its value. In the first 50 runs documented in the US, Quantec Force lowered costs by drilling an average of 30% farther and 25% faster than offset bits.

The Hughes Christensen Quantec Force line of PDC bits features newly engineered stabilization technology and next-generation cutters. (Image courtesy of Hughes Christensen)

Improving durability, ROP

Quantec Force incorporates several design features to improve durability and ROP. A proprietary bit dynamics model was used to optimize the force distribution for stability and drilling efficiency throughout the bit run. All the cutters engage the formation uniformly to minimize highly destructive bit whirl for increased penetration rates.

With conventional PDC bits, reduced weight-on-bit or drilling of interbedded formations generates low depth of cut, which frequently results in bit whirl. Whirl means the cutters are not engaging the formation uniformly and will eventually destroy the cutting structure, wasting energy and reducing ROP.

During testing on a downhole simulator, which replicates challenging field applications, Quantec Force technology demonstrated significant ROP improvement and durability at up to 240 rpm.

Wear-resistant cutters

Newly engineered, wear-resistant cutters used in the Quantec Force design stand up to extremely abrasive drilling applications. The cutters have an optimized carbide substrate interface that is critical for balancing cutter stress.

Using finite element analysis, the Baker Hughes diamond research team reduced residual stresses while relocating primary stresses away from the vulnerable cutting edge. The new cutters allow operators to achieve longer bit runs than earlier PDC technology.

Specifically engineered nozzle locations and optimized junk slot efficiency enhance the bit’s hydraulics and chip flow management to balance fluid flow, cutter cooling, and erosion resistance. The efficient cuttings removal achieved through improved hydraulics and chip flow management increases ROP and reduces bit balling.

Depth of cut control

Baker Hughes engineers also developed patented depth-of-cut control technology to reduce vibration, enhance tool face control and reduce premature cutter damage for longer bit life, higher ROP and optimized well placement. Multiple cutter rows that drill various lithologies with no performance degradation and diamond volume management to customize the bit profile and cutter layout round out the design features of Quantec Force bits.

Bit performs in Texas fields

In the challenging Barnett shale, the new bit drilled 1,873 ft (571 m) of Atoka sand and Bend conglomerate intervals at an average of 47 ft/hr while holding tangent to the kickoff point. The bit run saved the operator almost 35 hours of drill time and reduced costs by US $58,000 compared with offset wells.

At a well in Limestone County, Texas, a 77?8-in. Quantec Force Q507FX bit was used to drill through the ratty hard sand and soft shale sequences of the Travis Peak /Cotton Valley transition zone. The bit drilled 1,269 ft (387 m) at 21.3 ft/hr — 31% faster than the offset well average and 122% more footage than the average at offset wells in a 6-mile (9.6-km) radius. The run saved the operator more than 18 hours of drilling time, reducing costs by $24/ft.

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