Drillstring Vibrations: A New Generation Mechanism and Control Strategies

Abstract

Drillstring Vibrations: A New Generation Mechanism and Control Strategies W.D. Aldred; W.D. Aldred Anadrill/Schlumberger Search for other works by this author on: This Site Google Scholar M.C. Sheppard M.C. Sheppard Anadrill/Schlumberger Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Annual Technical Conference and Exhibition, Washington, D.C., October 1992. Paper Number: SPE-24582-MS https://doi.org/10.2118/24582-MS Published: October 04 1992 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Aldred, W.D., and M.C. Sheppard. "Drillstring Vibrations: A New Generation Mechanism and Control Strategies." Paper presented at the SPE Annual Technical Conference and Exhibition, Washington, D.C., October 1992. doi: https://doi.org/10.2118/24582-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Annual Technical Conference and Exhibition Search Advanced Search AbstractDamaging drillstring vibration has traditionally been associated with resonant behavior of the BHA. As a result modeling has concentrated on harmonic analysis of the drillstring. This has led to strategies for controlling vibrations based on 'tuning' the rotary speed and varying weight-on-bit. Using field and laboratory data we demonstrate that, in fact, once initiated, damaging transverse vibrations persist over a wide range of rotary speeds and that they depend on lithology, BHA design and hole gauge. We also show that downhole vibration can lead to increased torque and impaired ROP. This paper proposes a new mechanism for generating damaging vibration in which the transverse motion of the drillstring couples to the rotary motion during contact with the borewall. This analysis has led to some novel solutions to vibration problems. We present in this paper field examples of downhole shock measurements together with results from a full scale experimental investigation of the transverse vibration of rotating drill collars to support these conclusions.IntroductionSevere vibration of the BHA is common while drilling. Apart from the damaging effects of high shock levels, the transverse motion of the drillstring has several other consequences:Backwards whirl will produce very high bending stresses, particularly at the joint between a collar and stabilizer (ref. 1).Impacts with the borehole wall will tend to cause changes in gauge of either the hole or the drillstring components, bit and stabilizers. This can cause problems both with directional control and logging.Impacts of the drillstring with the borehole can lead to an increase in the surface torque required to drill and may adversely affect rates of penetration.In order to effectively reduce damaging transverse vibrations of the Bottom Hole Assembly (BHA) it is necessary to understand the mechanisms by which they are generated. The understanding of transverse drillstring vibration current in the literature is based on harmonic analysis of the BHA and is primarily concerned with the identification of resonant responses of the system, which are considered to be the primary source of vibrations. Using laboratory data from a full scale experiment with an instrumented rotating drill collar in conjunction with downhole vibration measurements it has been shown that resonant phenomena alone do not account for the drillstring behavior. In particular models based oil the harmonic behavior of the drillstring do not explain the response of the drillstring to variations in rotary speed, the effect of lithology, the occurrence of backwards whirl, or the magnitude of the shocks observed. The purpose of this paper is to propose an alternative mechanism which suggests new methods of vibration control. It will be demonstrated that downhole vibrations are highly nonlinear phenomena which makes prediction difficult, and unreliable.P. 353^ Keywords: lithology, rotary speed, borehole wall, coefficient, experiment, interaction, drillstring design, drilling operation, backward whirl, sandstone Subjects: Drillstring Design, Drilling Operations, Drill pipe selection This content is only available via PDF. 1992. Society of Petroleum Engineers You can access this article if you purchase or spend a download.