Vibrations in the drillstring are the result of interaction among the bit, the formation and the bottomhole assembly (BHA). These oscillations manifest in axial vibration, lateral motion and torsional modes. At lower frequencies, torsional behavior appears as stick-slip; at higher frequencies, it becomes high-frequency torsional oscillation (HFTO). When any of these modes exceeds thresholds, the energy intended for drilling turns into destructive motion—accelerating tool wear, damaging bits, reducing penetration and increasing nonproductive time.
The stakes are exceptionally high in the Bay of Thailand. Some wells reach bottomhole temperatures that push electronics, sensors and elastomers near their mechanical limits. Geological layering of faulted, stacked sands and compartmentalized reservoirs add complexity to trajectory and torque management. In formations of loosely consolidated sand, vibration magnifies erosion risk, accelerating tool wear and challenging completion integrity. In these mature fields with declining pressure, effective vibration mitigation is foundational to sustaining throughput, tool durability and predictability.
Field trials in the Bay of Thailand
To evaluate practical suppression strategies, an operator in the Bay of Thailand conducted trials comparing several drilling tools designed to mitigate different types or combinations of vibrations, benchmarked against offset wells.
In those trials, a cable design tool, NeoTork, demonstrated the ability to mitigate all encountered vibration modes rather than focusing on a single dysfunction. In four wells, through its high-frequency movement, the cable design tool maintained the drillbit’s depth-of-cut at a constant level, which prevented vibration excitation from becoming damaging dysfunctions. For example, torsional vibration amplitudes fell from more than 5 g to less than 2 g. This reduction in damaging vibrations allowed the driller to transmit more energy to the drillbit, allowing for a faster rate of penetration (ROP), which climbed 39% on average, with some individual well gains reaching 25% to 165% above offset baselines.
