Isubs: A New Generation of Autonomous Instrumented Downhole Tool

Desmette, Sebastian; Will, John J.; Coudyzer, Christophe; Le, Phi

doi:10.2523/92424-ms

Cited by 1 publication

(1 citation statement)

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“…For the current study, the authors utilized a dataset containing 50Hz downhole data recorded continuously during the course of drilling the well by a commercial DDR device (Desmette et al, 2005) as part of a drilling optimization effort for an application in the Permian basin. The dataset utilized here focuses on a 8 ¾" vertical section.…”

Section: High-frequency Downhole Vibration Data Setmentioning

confidence: 99%

For Better or Worse: Applications of the Transfer Matrix Approach for Analyzing Axial and Torsional Vibration

Shor

Dykstra

Hoffmann

et al. 2015

Day 3 Thu, March 19, 2015

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The response of the drilling system to axial and torsional vibration inputs has a significant impact on drilling performance. Usually the goal is to minimize dynamic response to limit the effects of potentially damaging phenomena in the low frequency range (e.g. bit bounce and torsional stick-slip) and high frequency range (e.g. axial chatter and torsional resonance). However, in some cases the goal is to maximize dynamic response, for example when introducing oscillation tools to overcome wellbore friction while directional drilling or to free stuck pipe. Whether the intention is to maximize or minimize, a suitable mathematical model is required. The model presented in this study uses the transfer matrix approach to predict how a harmonic vibration input propagates through the remainder of the drillstring. Novel features of the model include the ability to place the excitation source anywhere in the drillstring and to estimate damping effects due to Coulomb friction in directional wells.Model inputs include drillstring and bottom hole assembly composition, well survey data, surface equipment and drilling parameters. Drillstring components are modeled as spring or beam elements and the surface equipment is modeled as a mass-spring system. Bit-formation interaction is modeled as a spring, the stiffness of which can be adjusted to provide a boundary condition ranging from fixed to free. Damping due to material hysteresis and interaction with the drilling fluid is modeled using a velocitydependent term. Coulomb friction is modeled as an equivalent viscous damping coefficient. A harmonic excitation is specified at a given location in the drillstring and the responses at other locations in the system are computed via transfer matrices. This approach allows rapid characterization of the axial and torsional response of the drillstring in the frequency domain and may be applied to analyses of induced oscillation, such as from axial oscillation tools (AOTs), or unintended vibration, such as bit bounce.Case studies show that predicted frequency responses in the axial and torsional domain compare favorably with high sampling rate downhole and surface measurements, respectively. Additional case studies demonstrate how the model has been successfully applied to diagnose and resolve severe axial vibrations while drilling with roller cone bits. Finally, model predictions are compared with downhole acceleration measurements to evaluate effectiveness of axial oscillation tools while drilling with steerable motor systems. Recommended practices for device placement and drillstring configuration are provided based on the findings from these studies.

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Section: High-frequency Downhole Vibration Data Setmentioning

confidence: 99%