Dramatically reduce bit related torque
TorkBuster® Technology by Ulterra
Ulterra’s patented TorkBuster tool is the only drilling tool that adds a torsional impact directly to the drill bit. Just like an impact driver, the TorkBuster converts hydraulic energy into torsional hammering action that enables aggressive PDC bits to fracture and drill through even the hardest rock at higher depths of cut. Also, failing the rock more frequently prevents stick-slip, a destructive process where torsional energy is cyclically stored up and released from the drill string. That means that not only do you drill faster, but your bit and BHA stay drilling longer.
The phenomenon of stick-slip is well researched and documented within the drilling industry. Bit-related stick-slip is often a problem when drilling hard formations with a Polycrystalline Diamond Compact (PDC) fixed-cutter bit. Under optimum drilling conditions, the PDC bit shears formation with a constant depth of cut (DOC). When a harder formation is encountered the bit loses DOC and more weight-on-bit (WOB) must be added to engage the PDC cutters in formation. Many times, however, the reactive torque of the formation cannot be overcome immediately – in this case the bit slows or stops (stick) while torque is stored in the drill string until the torque required to fail formation is achieved and the bit violently rotates (slip). This action can cause damage to PDC cutters and other drill string components, resulting in reduced bit and tool life as well as poor rate of penetration (ROP).
Traditional methods for mitigating stick-slip involve adjusting operating parameters to avoid the stick-slip phase, pacifying the PDC bit by using higher blade counts, higher backrakes, etc., or even by using less-efficient roller cone or diamond-impregnated bits. These methods have only been marginally successful and reduce overall drilling efficiency and lead to reduced potential ROP.
Inside TorkBuster a rotating hammer and anvil assembly – driven by drilling fluid pumped through the tool – creates low level torsional impacts that are transferred to an independent bit drive sub. This mechanism delivers additional energy directly to the bit in the form of high frequency torsional impulses. Drilling RPM and WOB is transmitted to the bit via the TorkBuster housing which utilizes a castellated drive mechanism. Torsional impulse is transmitted independently to the bit drive sub. The castle section therefore isolates the additional energy from travelling back up the string. In the event the TorkBuster ceases to function, it becomes an inert component of the BHA. There is no need to stop drilling or pull out of hole as the bit will continue to turn and drill ahead.
Drilling applications where the TorkBuster adds value range across a broad spectrum. However, they are usually identified where drilling mechanics and dynamics are known to be dysfunctional for some reason. This may be poor motor quality, small or lightweight drill string, extremely high mud weight, and other applications where it has become difficult to transfer consistent weight and torque to the PDC bit. In some cases these applications are identified by the continued use of roller cones or diamond impregnated bits.
Get these TorkBuster® Advantages
- Reduced drilling cost by improving bit performance
- Effective alternative to multiple Roller cone runs
- Enables use of more aggressive PDC bits
- Higher ROP in hard formations
- Increases PDC bit life resulting in fewer trips
- Improved BHA life- mitigates damage associated with stick slip
- Improved tool face control in directional applications
- Formation threshold = torque required to fail the formation and the level of reactive torque transmitted into the BHA
- If formation threshold changes erratically, reactive torque becomes erratic, causing BHA instability and stick-slip
- TorkBuster impulse torque= high frequency torsional energy provided by TorkBuster
- Enables higher formation threshold to be drilled without increasing reactive torque transmitted into BHA
- With TorkBuster reactive torque is transmitted smoothly into the BHA reducing vibrations and stick-slip TorkBuster is available for hole sizes from 6” (152mm) to 9 7/8” (250mm)
- Mitigates bit related “Stick Slip”
- Generates Torsional Energy
- Smooths out reactive torque into the BHA
- Directs high frequency rotational impact forces to the bit