A stochastic analysis of the coupled lateral–torsional drill string vibration

This paper discusses longitudinal and angular drill-string vibrations and supporting field measurements taken with a special downhole recording instrument. Computer programs based on the theory are used to calculate longitudinal and angular vibrations (caused by periodic bit motions) along the drill string; field measurements made during actual drilling operations are used to check computer calculations. The main difference between this and other theory on the same problem is the inclusion of friction, which acts along the length of a drill string and impedes longitudinal and angular vibrations. For the sake of simplicity, the effect of different types of friction, such as fluid, rubbing, and material, which act along the string, is approximated by the effect produced by viscous friction. This approximation is generally accepted and appears to give adequate results for the drill-string vibration problem.

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Formation Prediction Model based on Drill String Vibration Measurements Using Laboratory Scale Rig

10.2118/166793-ms ◽

2013 ◽

Author(s):

Abdolali Esmaeili ◽

Behzad Elahifar ◽

Rudolf Konrad Fruhwirth ◽

Gerhard Thonhauser

Keyword(s):

Prediction Model ◽

Drill String ◽

Laboratory Scale ◽

Vibration Measurements ◽

String Vibration ◽

Model Based

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A Periodic Noise Separation Method Research of well Field Three-Dimensional Drill String Vibration Signal

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.318.27 ◽

2013 ◽

Vol 318 ◽

pp. 27-32

Author(s):

Hao Cheng Wu ◽

Yong Shou Dai ◽

Wei Feng Sun ◽

Li Gang Li ◽

Ya Nan Zhang

Keyword(s):

Independent Component Analysis ◽

Vibration Signal ◽

Component Analysis ◽

Drill String ◽

Independent Component ◽

Analysis Algorithm ◽

String Vibration ◽

Periodic Noise ◽

Well Field ◽

Independent Component Analysis Algorithm

Periodic noise is an important manifestation of the drill string vibration signal noise. In order to extract the characteristics of the signals which reflect the situation of the tools in drilling, the periodic components which influence the original drill string vibration signal in the well field were researched and the independent component analysis algorithm which is on the basis of negative entropy for periodic vibration noise separation was adopted. At the same time, the effect of algorithm demixing was improved where periodic noise components which existed in three directions of drill string vibration signals were used, combining with the improved particle swarm optimization algorithm to seek the optimal mixed matrix by which the multi-channel mixed-signal of independent component analysis algorithm could be structured. This method in operation was fast. And after separation each signal was of high similarity. Through the experimental simulation, the method was proven effective in the drill string vibration periodic noise signal separation.

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Research on Cepstrum Analysis of Drill String Vibration and Extraction of Bit Source Signals

Chinese Journal of Geophysics ◽

10.1002/cjg2.1537 ◽

2010 ◽

Vol 53 (4) ◽

pp. 684-692

Author(s):

He-Zhen WU ◽

Hong-Kui GE ◽

Ding-Hui YANG ◽

Bin LU ◽

Lai-Ju HAN ◽

...

Keyword(s):

Drill String ◽

String Vibration ◽

Cepstrum Analysis ◽

Source Signals

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ROP Modeling using Neural Network and Drill String Vibration Data

10.2118/163330-ms ◽

2012 ◽

Cited By ~ 3

Author(s):

Abdolali Esmaeili ◽

Behzad Elahifar ◽

Rudolf Konrad Fruhwirth ◽

Gerhard Thonhauser

Keyword(s):

Neural Network ◽

Drill String ◽

Vibration Data ◽

String Vibration

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A Modified Model for Friction Reduction by Vibrating Drill-String Longitudinally

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.535.597 ◽

2014 ◽

Vol 535 ◽

pp. 597-601 ◽

Cited By ~ 2

Author(s):

Peng Wang ◽

Hong Jian Ni ◽

Zhi Na Li ◽

Rui He Wang

Keyword(s):

Drill String ◽

Friction Reduction ◽

Contact Theory ◽

Rock Surface ◽

Modified Model ◽

String Vibration ◽

Tangential Stiffness ◽

Proposed Model ◽

Drilling Method ◽

Coulomb Model

Drill-string vibration excitation longitudinally is a potential drilling method for reducing friction between drill-string and borehole rock. This article assumes that borehole rock surface is composed of elliptical asperities, based on elastic-plastic contact theory, a modified model for friction reduction by vibrating drill-string longitudinally is developed. The results show that the tangential stiffness of borehole rock surface decreased with increasing ovality of asperity. Further, at the same ovality, thin and tall asperity has bigger tangential stiffness than short and fat asperity. Only when the tangential stiffness of borehole rock is greater than a certain threshold, the friction force calculated by proposed model in this paper can appear reverse phenomenon. When the tangential stiffness tends to infinity, the result tends to Coulomb model. The conclusions provide basis for research and application of drill-string vibration longitudinally friction reduction technology.

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