Results 111 to 120 of about 1,167 (156)

ANALYSIS OF DRILLSTRING VIBRATIONS USING ACTIVE CIRCUITS

2006 GSW Proceedings, 2022
Comment: 18 ...
Chaitanya Kancharla, M. A. Elsayed, Cherif Aissi   +2 more
openaire   +2 more sources

Field Measurements of Downhole Drillstring Vibrations

SPE Annual Technical Conference and Exhibition, 1985
ABSTRACT NL's Wire Telemetry System was used in the field to provide high-data-rate measurements of downhole forces, accelerations, pressures and formation properties. This paper describes, and briefly discusses, downhole longitudinal and lateral vibrations and their correlation with formation characteristics.
S.F. Wolf, M. Zacksenhouse, A. Arian
openaire   +1 more source

Self-excited vibrations of a drillstring bit

International Applied Mechanics, 2013
The whirling vibrations of a rotating drillstring bottom-hole assembly subject to the moment of friction are analyzed qualitatively. A problem statement and solution are given. The self-excitation of vibrations is simulated. It is established that during the self-excitation of whirling vibrations, the axial line of the drill bit can slowly and rapidly ...
V. I. Gulyaev, P. Z. Lugovoi, E. I. Borshch   +2 more
openaire   +1 more source

Control of Stick-Slip Vibration in Drillstrings with Multiple Frequencies

2020 American Control Conference (ACC), 2020
Torsional vibration is a common phenomenon, known as stick-slip in oil-well drilling, that causes poor drilling performance, downhole tool failure, and bit wear. It is observed that stick-slip vibration- generally occur at multiple frequencies. To help mitigate torsional vibration, a dynamic model of drillstring is first studied where analytical ...
Zhijie Sun, Sujian Huang
openaire   +1 more source

Predictive control of torsional drillstring vibrations

2016 20th International Conference on System Theory, Control and Computing (ICSTCC), 2016
In this paper, the control problem of torsional vibrations occurring along a rotary drillstring system is approached. This task is performed using a predictive control strategy, based on a discrete-time model of the system, taking into account the constraint on control input.
Andreea Soimu, Florin Stinga
openaire   +1 more source

The Genesis of Torsional Drillstring Vibrations

SPE Drilling Engineering, 1992
Summary Inherent drilling characteristics of polycrystalline diamond compact (PDC) bits alone can be sufficient to excite severe torsional drillstring vibrations. The work presented here augments previous findings that torsional vibrations can result from the drilling characteristics of the bit itself.
openaire   +1 more source

COUPLED TORSIONAL AND BENDING VIBRATIONS OF ACTIVELY CONTROLLED DRILLSTRINGS

Journal of Sound and Vibration, 2000
Abstract The dynamics of actively controlled drillstrings is studied. The equations of motion are derived using a lumped parameter model in which the coupling between torsional and bending vibrations is considered. The model also includes the dynamics of the rotary drive system which contains the rotary table, the gearbox and an armature controlled ...
Yigit, AHMET SALİH, Christoforou, A.P.
openaire   +2 more sources

A Modal Approach for Chaotic Vibrations of a Drillstring

Volume 1: 22nd Biennial Conference on Mechanical Vibration and Noise, Parts A and B, 2009
The purpose of this paper is to present a methodology to predict vibrations of drilllstrings for oil recovery service. The paper extends a previous model in the literature to include drill collar flexibility utilizing a modal coordinate condensed, finite element approach.
Kathira Mongkolcheep, Alan Palazzolo, Annie Ruimi, Randall Tucker   +3 more
openaire   +1 more source

Method and apparatus for suppressing drillstring vibrations

The Journal of the Acoustical Society of America, 2003
Apparatus and methods are described for isolating in a drillstring a device from acoustic noise by introducing between the device and a source of acoustic vibration an noise isolating apparatus, wherein the noise isolating apparatus has adjacent zones of different acoustic impedance.
openaire   +1 more source

Lateral Drillstring Vibrations in Extended-Reach Wells

IADC/SPE Drilling Conference, 2000
Abstract Drillstring dynamics and hole cleaning problems are some of the most important limiting factors in extended reach applications. Here, long sections of the drillstring lie on the low side of the wellbore while rotating. When the rotary speed exceeds a critical threshold the drillstring starts to "snake", sliding up and down the ...
G. Heisig, M. Neubert
openaire   +1 more source