Abstract
High frequency torsional oscillations (HFTO) is a severe problem in drilling system including a bottom hole assembly (BHA) , in particular with a rotary steerable system (RSS). It is related to drilling hard and dense formation with PDC drill bits. HFTO can be prevented with damping that is applied to the critical HFTO-modes of the drilling system. The damping that is achievable for a damping element is largest when the damping element is placed at the bit and decreases with distance from the drill bit. Therefore, a placement of a damper within the BHA and close to the drill bit is preferred over a placement above the BHA in order to achieve significant damping. The effectiveness of the inertia damper is increasing significantly with the diameter (with the power of 4). Therefore, a wired connection through a damping tool is optimal close to the center of the tool which would not consume any design space for the damper (inertia element) at the outer diameter of the tool. A "cable tube" can be used for this purpose. The cable tube can be connected at the lower and upper end of the tool through adapter subs or through a similar design with flow diverters. The cable tube is a thin metal tube that includes the cables, where the high flexibility provides protection against large deflections and eliminates damages through vibrations such as lateral vibrations.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
Baker Hughes Company, "Wired through BHA HFTO damper with center electrical connection", Technical Disclosure Commons, (February 03, 2025)
https://www.tdcommons.org/dpubs_series/7796