Design and Field Deployment of a Torsional Vibration Damper

Abstract

AbstractDifferent vibration phenomena and vibration dysfunctions are excited by the drilling process. The associated dynamic loads result in downhole tool failures and inefficient drilling if not properly managed. Vibration mitigation strategies based on adjustment of operational parameters often compromise the rate of penetration (ROP). The purpose of downhole tools for vibration mitigation is to enlarge the envelope of drilling parameters with low levels of vibrations. The associated more aggressive drilling parameters enable a higher ROP. A torsional vibration damper that is designed to mitigate high-frequency torsional oscillations (HFTO) is introduced in this work along with the results of first field deployments.A damping-threshold needs to be exceeded by a damper to mitigate self-excited HFTO. The damping threshold is defined through the energy input resulting from the bit-rock interaction and depends on the instantaneous operational parameters. The design space to provide damping, however, is limited. Thus design and dimensioning of the torsional vibration damper is optimized based on theoretical insights, downhole vibration data analysis, modeling and simulations, and laboratory testing at different scale. This process is presented in the paper.The placement of the damper elements within the drilling system has been identified as a critical task to effectively dampen the critical modes related to HFTO. The simulated results for the BHA that is deployed in the field are presented. In a case study the first field deployments of the torsional vibration damper are discussed. The results of the damper deployments and a comparison to offset well data prove that the damper effectively mitigates HFTO. Snapshots of high-speed vibration data sampled with 1000 Hz are analyzed and related to the modeling results. The suppression of HFTO enabled the application of more aggressive operational parameters and led to an increase in the ROP compared to benchmark runs. First trends prove a high reliability of the BHA with torsional vibration damper tool.The torsional vibration damper has been successfully introduced in the field and has proven to effectively suppress HFTO. A holistic methodology has been developed that allows for an application specific optimization of the damper deployment. The torsional vibration damper enables a higher rate of penetration at low levels of vibrations and an increased reliability of the tools deployed and, ultimately, decreases the well delivery cost significantly.