Abstract
Self-tuned friction damper for mitigation of high frequency torsional oscillations (HFTO) in a bottom hole assembly (BHA) for drilling boreholes in the earth crust has been described already. It is especially covering the higher frequency content of HFTO, since the high damping effect is gradually declining towards a standard friction damper if smaller HFTO frequencies below the self-tuned frequency occur. In a tuned system the effect is opposite. A tuned system can be modeled as a spring in parallel to a friction contact (or other dissipative forces). The damping effect close to the tuning frequency is again high close to it but gradually declining towards higher frequencies. A combination is beneficial, because both the lower and the high frequency range can be tuned with factors higher damping compared to the pure friction damper. Whereas the mechanical spring that is used for the self-tuning effect has rather small requirements regarding the spring design (especially the displacement within the spring), the spring that is used for the tuned effect requires a large range of displacement between the inertia and the BHA in which the damper is installed. Therefore, it is rather tough to design. A viscous fluid like silicon fluid has a stiffness and a damping factor, which are both dependent on temperature, pressure, frequency, amplitude.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
"Self-tuned friction damper tuned with silicon fluid/viscous fluid", Technical Disclosure Commons, (November 05, 2025)
https://www.tdcommons.org/dpubs_series/8841