A Comprehensive Fluid Coupled Lateral Drill String Vibration Model Based on Classical Vibration Theories

2018 ◽  
Author(s):  
Abhijeet D. Chodankar ◽  
Abdennour Seibi
Keyword(s):  
Dynamic Response ◽  
Shear Deformation ◽  
Natural Frequency ◽  
Circular Cross Section ◽  
Drill String ◽  
Rotary Inertia ◽  
Compression Load ◽  
String Vibration ◽  
Vibration Model ◽  
Fluid Damping

The drilling industry has been suffering from huge monetary losses and non-productive time due to wear and fatigue of the drill string components. Vibration mitigation plays a pivotal role in extending the life of drill string components. The development of a comprehensive drill string vibration model will help in classifying the causes of drill string vibrations and helps in planning pro-active measures to suppress it. In the past, researchers have developed models based on factors like drill string length, axial compression load, lateral loads, shear deformation, rotary inertia and fluid damping. The four classical engineering vibration theories will be discussed in detail with the addition of fluid stiffness and fluid damping. This paper develops a drill string vibration model considering the effects of bending, translational inertia, rotary inertia, shear deformation, fluid stiffness and fluid damping. The drill string is considered as a cantilever beam of a circular cross-section immersed in water with equal pressure on both sides. The water is considered to be a spring and dash-pot model in parallel. It adopts a classical solution methodology based on D’Almbert’s principle. The eigen values, normalized mode shape, natural frequencies, orthogonality conditions and dynamic response equations are derived for all the theories. Natural Frequency and Dynamic response of the drill string are used to make informed decisions. Numerical simulation results show the influence of all the factors on vibration damping of the drill string. A critical understanding of the effects of all the above factors individually and in tandem will help in adopting a novel drilling strategy. To conclude, a complete step-by-step methodology for the proposed comprehensive drill string vibration model is put forth to determine the natural frequency and dynamic response of the drill string.

scholarly journals Effect Of Drill String Rotation On The Dynamic Response Of Drilling Risers

2015 ◽  
Vol 20 (3) ◽  
pp. 503-516 ◽  
Author(s):  
I.E. Major ◽  
A. Big-Alabo ◽  
S. Odi-Owei
Keyword(s):  
Differential Equation ◽  
Free Vibration ◽  
Dynamic Response ◽  
Natural Frequency ◽  
First Principles ◽  
Rotational Speed ◽  
Variable Coefficient ◽  
Drill String ◽  
Flexural Response ◽  
Free Vibration Response

Abstract The effect of the rotation of a drill string on the response of a drilling riser has been studied. A governing equation for the flexural response that incorporates the effect of the drill string rotation is developed from first principles, and the resulting differential equation is found to have a variable coefficient, which is a function of the drill string rotational speed. Results simulated for the free vibration response show that the drill string rotation reduces the natural frequency and increases the amplitude of vibration of the drilling riser. The implication of these findings is that neglecting the effect of rotation of the drill string leads to under-estimation of the deflection and over-estimation of the natural frequency. Further analysis reveals that for a drilling riser of given dimensions, a drill string rotational speed exists at which the natural frequency of the drilling riser is theoretical equal to zero, and this rotational speed is the threshold rotational speed.

Effects of Axial Compression Load, Borehole Clearance, and Contact Force Using Axial-Lateral Fluid Coupled Drill String Vibration Model

2019 ◽  
Author(s):  
Abhijeet D. Chodankar ◽  
Abdennour Seibi
Keyword(s):  
Axial Compression ◽  
Contact Force ◽  
Drill String ◽  
Contact Forces ◽  
Compression Load ◽  
String Vibrations ◽  
Vibration Model ◽  
Bottom Hole Assembly ◽  
Drilling Cost ◽  
Dominant Frequencies

Abstract Drill string vibrations have resulted in an increase in non-productive time, drilling cost, and a need for drill string system optimization in the oil and gas industry. Higher vibrations can lead to washout, blow-out phenomena, and a rapid wear and tear of drill string components. An in-depth understanding of the root causes of the drill string vibrations is of utmost importance. The effects of mass imbalance, bottom hole assembly (BHA) design, weight on bit, hole angle, hole size, RPM, drilling fluid viscosity, bit and formation type on drill string vibrations have been studied in the past. The main objective of this paper is to propose a novel drill string vibration model taking into consideration the effects of axial compression load, borehole clearance, and contact force in conjunction with Euler-Bernoulli, Rayleigh, and Shear beam theories. The proposed model studies the effects of axial compression load, borehole clearance, and stiffness on the natural frequency and frequency response of drill string. The drill string is considered as a cantilever beam with a circular cross-sectional area in a horizontal drilling condition, while the fluid (water) around it is considered as a spring and dashpot model. Drill string vibrations are modeled based on a distributed system approach. The forces acting on the cantilever beam element are axial compression load, shear forces, bending moment, fluid stiffness and damping forces. A fourth order partial differential equation is derived and the solution is obtained based on the assumed modes approach to obtain the characteristic equation and mode shapes. Natural frequency is determined using the eigen values obtained from the characteristic equation. The orthogonality conditions are further derived to decouple the derived equation. The drill string is initially assumed unbounded, hence the amount of contact force required to restrict the drill string within the borehole is determined. An iterative process is employed to restrict the drill string deflection within the borehole with a corresponding increase in the stiffness of the drill string system. This will help in determining the experienced down hole contact forces and the stiffness requirements of the bottom hole assembly. Dominant frequencies are identified, compared with field results, further guiding the operator to avoid rotating the drill string at particular frequencies. A detailed study of the effects of contact forces, borehole clearances, and axial compression load will provide comprehensive guidelines in BHA design of drill string assembly. To conclude, this paper proposed an accurate model to identify dominant frequencies and provides a thorough BHA design guidelines for the drill string design manufacturers and field operators leading to a reduction in drilling cost and unproductive time, and environmentally friendly drilling operations.

Dynamic Response of Buried Pipelines—An Elasticity Solution

1990 ◽  
Vol 112 (3) ◽  
pp. 291-295 ◽  
Author(s):  
B. K. Mishra ◽  
P. C. Upadhyay
Keyword(s):  
Dynamic Response ◽  
Shear Deformation ◽  
Theory Of Elasticity ◽  
P Wave ◽  
Wave Number ◽  
Rotary Inertia ◽  
Angle Of Incidence ◽  
Elasticity Solution ◽  
Buried Pipelines ◽  
Surrounding Soil

This paper presents a theory of elasticity solution of the axisymmetric steady-state dynamic response of a buried pipeline excited by a plane longitudinal wave (P-wave) traveling in the surrounding soil. Both the pipeline and the ground have been assumed to be linearly elastic, homogeneous and isotropic. Linear elasticity equations of motion have been solved simultaneously for the pipeline and the surrounding soil. A perfect bond between the pipeline and the ground has been assumed. The midplane deformations of the pipeline have been plotted against the nondimensional wave number of the incident wave, for different soil condition and angle of incidence of the wave. The results of the present work have been compared with those found by using a shell theory which includes the effect of shear deformation and rotary inertia. It has been found that excellent agreement exists between the results obtained by the two approaches. The present work concludes that the use of shell model, including effects of shear deformation and rotary inertia, is justified for the analysis of dynamic response of buried pipelines excited by seismic waves traveling in the ground.

scholarly journals Analytical Expressions for Frequency and Buckling of Large Amplitude Vibration of Multilayered Composite Beams

2011 ◽  
Vol 2011 ◽  
pp. 1-9
Author(s):  
R. A. Jafari-Talookolaei ◽  
M. H. Kargarnovin ◽  
M. T. Ahmadian ◽  
M. Abedi
Keyword(s):  
Shear Deformation ◽  
Natural Frequency ◽  
Large Amplitude ◽  
Composite Beam ◽  
Numerical Study ◽  
Harmonic Balance Method ◽  
Rotary Inertia ◽  
Displacement Fields ◽  
Amplitude Vibration ◽  
Large Amplitude Vibration

The aim of this paper is to present analytical and exact expressions for the frequency and buckling of large amplitude vibration of the symmetrical laminated composite beam (LCB) with simple and clamped end conditions. The equations of motion are derived by using Hamilton's principle. The influences of axial force, Poisson effect, shear deformation, and rotary inertia are taken into account in the formulation. First, the geometric nonlinearity based on the von Karman's assumptions is incorporated in the formulation while retaining the linear behavior for the material. Then, the displacement fields used for the analysis are coupled using the equilibrium equations of the composite beam. Substituting this coupled displacement fields in the potential and kinetic energies and using harmonic balance method, we obtain the ordinary differential equation in time domain. Finally, applying first order of homotopy analysis method (HAM), we get the closed form solutions for the natural frequency and deflection of the LCB. A detailed numerical study is carried out to highlight the influences of amplitude of vibration, shear deformation and rotary inertia, slenderness ratios, and layup in the case of laminates on the natural frequency and buckling load.

Investigation of Strength and Dynamic Characteristics for the Rolling Mill

2013 ◽  
Vol 706-708 ◽  
pp. 1405-1408
Author(s):  
Xi Ping Guo ◽  
Shuang Zhou
Keyword(s):  
Natural Frequency ◽  
Dynamic Characteristics ◽  
Rolling Mill ◽  
Maximum Stress ◽  
Weak Link ◽  
Deformation Analysis ◽  
Vibration Model ◽  
Strength And Stiffness ◽  
Stress And Deformation ◽  
Diagram Analysis

Stress and deformation analysis of 950 mill housing was done by means of ANSYS to calculate the maximum stress and deformation. Strength and stiffness of the mill roll were checked to meet requirements. Carries on the modal analysis to the rolling-mill housing, obtains its first 10 steps the natural frequency and the mode of vibration, through the vibration model diagram analysis frame of the weak link,and it is significant for similar mill housing designs.

Dynamics Analysis of Refrigeration Compressor Based on Finite Element and Experimental Modes

2012 ◽  
Vol 499 ◽  
pp. 238-242
Author(s):  
Li Zhang ◽  
Hong Wu ◽  
Yan Jue Gong ◽  
Shuo Zhang
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Modal Analysis ◽  
Natural Frequency ◽  
High Precision ◽  
3D Model ◽  
Finite Element Models ◽  
Dynamics Analysis ◽  
Response Characteristics ◽  
Dynamic Response Characteristics

Based on the 3D model of refrigeration's compressor by Pro/E software, the analyses of theoretical and experimental mode are carried out in this paper. The results show that the finite element models of compressor have high precision dynamic response characteristics and the natural frequency of the compressor, based on experimental modal analysis, can be accurately obtained, which will contribute to further dynamic designs of mechanical structures.

The Research on Natural Characteristic and Eigensensitivity of Ravingneaux Compound Planetary Gear Sets

2013 ◽  
Vol 446-447 ◽  
pp. 590-596
Author(s):  
Bo Qian ◽  
Shi Jing Wu
Keyword(s):  
Natural Frequency ◽  
Planetary Gear ◽  
Torsional Stiffness ◽  
Ring Gear ◽  
Vibration Model ◽  
Planetary Gear Sets ◽  
Planet Gear ◽  
Natural Characteristic ◽  
Gear Ring ◽  
The Moment

The dynamic model of Ravingneaux compound planetary gear sets has been built. Then the Natural frequency and vibration model have been solved in the Ravingneaux compound planetary gear sets. The eigensensitivity to parameters have been researched based on the dynamical model. The varying trend of natural frequency according to the varying of parameters have been researched, which include gear mass (sun gear, ring gear , or planet gear), the moment of inertia of gears, the support stiffness , the torsional stiffness.

Nonlinear Dynamic Response and Buckling of Damaged Composite Pipes Under Radial Impact

2006 ◽  
Author(s):  
Wenyong Tang ◽  
Tianlin Wang ◽  
Shengkun Zhang
Keyword(s):  
Dynamic Response ◽  
Shear Deformation ◽  
Nonlinear Dynamic ◽  
Shear Deformation Theory ◽  
Nonlinear Dynamic Response ◽  
Nonlinear Dynamic Equations ◽  
Geometric Deformation ◽  
Initial Geometric Imperfections ◽  
Set Up ◽  
Composite Pipes

In this paper, the nonlinear dynamic response and buckling of damaged composite pipes under radial impact is investigated. A model involving initial geometric deformation, delamination and sub-layer matrix damage is set up for theoretical analysis. Based on the first order shear deformation theory, the nonlinear dynamic equations of the composite pipe considering transverse shear deformation and initial geometric imperfections are obtained by Hamilton’s theory and solved by a semi-analytical finite difference method. The effects of damage on the dynamic response and buckling of composite pipes are discussed.

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