BicentricDrill (BD) Bi-Center PDC Bits
Eccentric Design for Enlarged Borehole Drilling
The BicentricDrill (BD) series features an innovative eccentric cutting profile that drills an enlarged borehole larger than the bit body diameter in a single pass. This bi-center design eliminates the need for separate underreaming runs, saving significant rig time while providing the casing clearance and annular space required for successful well construction in challenging formations.
Request a Quote View SpecificationsKey Features
Eccentric Design
Offset cutting structure creates a borehole larger than the bit body, providing additional casing clearance without requiring a separate underreaming operation.
Single-Pass Efficiency
Drills and underreams simultaneously, eliminating a complete trip and saving 12-24 hours of rig time compared to conventional drill-then-underream approaches.
Stabilized Drilling
Integral stabilization features maintain the bit on center while the eccentric cutting structure generates the enlarged hole profile consistently.
Adjustable Enlargement
Multiple BD configurations available to produce various enlargement ratios, matching the specific casing clearance requirements of each well design.
Technical Specifications
| Parameter | Value |
|---|---|
| Series | BicentricDrill (BD) |
| Bit Type | Bi-Center PDC |
| Body Material | Steel |
| Pilot Diameter | 152.4 mm (6") to 311.1 mm (12 1/4") |
| Enlarged Hole Diameter | Up to 115% of pilot diameter |
| Formation Hardness | Soft to Medium |
| Number of Blades | 4 to 7 |
| Cutter Size | 13 mm / 16 mm |
| Connection Type | API Regular Pin |
| Nozzle Configuration | Interchangeable nozzles |
| Stabilization | Integral near-bit stabilizer |
| Recommended RPM | 80 - 180 RPM |
Application Areas
Casing Clearance Enhancement
Creates the enlarged borehole needed for proper casing centralization and cement placement in sections with tight clearance requirements.
Swelling Shale Mitigation
Enlarged hole diameter provides additional annular space to accommodate shale swelling, reducing the risk of stuck pipe and casing running difficulties.
Cement Volume Optimization
Controlled enlargement provides consistent annular space for optimal cement column thickness, improving zonal isolation quality.
Gravel Pack Preparation
Creates enlarged sections for gravel pack completions where additional annular volume is required around the screen assembly.
Related Products
Request a Quote for BicentricDrill (BD)
Contact our technical team for pricing, availability, and custom configurations. We provide fast delivery across the UAE and the entire Middle East region.
BicentricDrill (BD): One-Pass Solution for Enlarged Boreholes
The BicentricDrill (BD) series from VBM introduces an elegant engineering solution to the common drilling challenge of creating enlarged boreholes. In many well designs, the borehole must be larger than the standard bit diameter to accommodate casing, provide adequate cement column thickness, or allow for formation movement such as shale swelling. Traditionally, this requires a separate underreaming run after the pilot hole is drilled, adding significant time and cost to the operation.
The BD bi-center design eliminates this additional step by incorporating an offset cutting structure that drills an enlarged hole in a single pass. As the bit rotates, the eccentric profile sweeps a circular path larger than the bit body itself, creating a borehole up to 15 percent larger in diameter. This approach combines the drilling and underreaming operations into one trip, saving operators 12 to 24 hours of rig time per section depending on well depth and conditions.
Maintaining hole quality with a bi-center design requires careful engineering of the stabilization system. The BD series incorporates integral near-bit stabilization features that keep the bit centered in the borehole while allowing the eccentric cutting structure to generate the enlarged profile consistently. This prevents spiraling, ensures uniform hole enlargement, and produces a wellbore suitable for casing running and cementing operations.
VBM Middle East offers BicentricDrill (BD) bits in a range of pilot diameters and enlargement ratios to match your specific well design requirements. Our engineering team can assist with selecting the appropriate BD configuration based on your casing program, formation characteristics, and drilling parameters. Contact our Dubai office for availability and technical support for your next well that requires enlarged borehole capability.