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.
Ulterra’s unique TorkBuster tool dramatically reduces bit related torque and stick-slip problems adding significant efficiency to drilling operations.
Ulterra is dedicated to maximizing the efficiency of oil and gas drilling operations through the use of cutting edge steel and matrix PDC bits and innovative application technologies. Throughout the world’s drilling basins we are building our reputation on proven performance. When every run counts, let us show you how we can improve your drilling efficiencies and lower your costs.
Ulterra CounterForce? and TorkBuster? a Winning Combination for Major Operator in Central Australia A major operator in central Australia recently achieved significant time and cost savings thanks to the combination of the Ulterra TorkBuster matched with the U513M CounterForce drill bit. The TorkBuster – Ulterra’s anti stick-slip torsional impact tool – reduces drilling time, preserves bit life and saves a bit trip.
The combination of TorkBuster and CounterForce proved to be a rock destruction solution within the challenging Permian, with the operator increasing ROP by 52% and achieving total savings of $150,000.
The Tools in Detail
TorkBuster reduces bit-related torque and stick-slip problems, adding significant efficiency to drilling operations. The feedback received form operators includes improved stability and reduced stick-slip; smoother reactive torque in BHA; improved bit life and ROP; extended bit range and enhanced directional control.
CounterForce is Ulterra’s PDC drill bit technology that uses a unique cutter configuration to lower bit reactive torque and vibration. Unlike traditional PDC bits, the cutters work together to lower lateral vibration and increase crack propagation. The CounterForce cutting structure is engineered to slice through rock while maintaining a more consistent torque signature, thus increasing stability and ROP.
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