Modeling and Control of Coupled Torsional and Lateral Vibrations in Drill Strings

2015 ◽  
Author(s):  
Liu Hong ◽  
Jaspreet Singh Dhupia
Keyword(s):  
Sliding Mode ◽  
Good Control ◽  
Friction Torque ◽  
Lumped Parameter Model ◽  
Oil Well ◽  
Lateral Instability ◽  
Stick Slip ◽  
Rock Interaction ◽  
Lateral Vibrations ◽  
Lumped Parameter

Excessive vibrations of the drill strings, e.g., the stick-slip vibration, are the primary cause of premature failures and drilling inefficiencies in oil well drilling. To investigate and suppress such vibrations, this paper studies the dynamics of drill strings using a lumped parameter model, in which both the torsional stick-slip and lateral vibrations are taken into consideration. The friction torque due to the downhole bit-rock interaction, which plays a key role in stick-slip vibration, is modeled as a hysteretic dry friction function. Simulated results of this developed model are shown to have a close qualitative agreement with the field observations in terms of stick-slip vibrations. Afterwards, a sliding mode controller is applied to mitigate the undesired vibrations of drill strings. A good control performance in suppressing the stick-slip phenomenon is demonstrated for the proposed controller. However, numerical simulations also demonstrate that the control action can excite lateral instability in the system, which can result in impacts between the drill collars and the borehole wall due to the large amplitude in lateral vibrations. Thus, a proper choice of the control parameters is essential to suppress the vibrations in the drill strings. The developed lumped parameter model describing the coupled torsional and lateral response in the controlled drill strings presented in this paper can be used to aid in offline tuning of those control variables.

Design and HIL Validation of an Effective Super-Twisting Controller for Stick-Slip Suppression in Drill-String Systems

2021 ◽  
Author(s):  
Abdelbasset Krama ◽  
Mohamed Gharib ◽  
Shady S. Refaat ◽  
Alan Palazzolo
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Sliding Mode ◽  
Drill String ◽  
Experimental Investigations ◽  
Small Scale ◽  
Oil Well ◽  
Stick Slip ◽  
Rock Interaction ◽  
The Real

Abstract This paper presents a novel controller for drill string systems based on a super-twisting sliding mode theory. The aim is to eliminate the stick-slip vibration and maintain a constant drill string velocity at the desired reference value. The proposed controller inherently attenuates the torsional vibration while ensuring the stability and high efficiency of the drill string. A discontinuous lumped-parameter torsional model of vertical drill strings based on four components (rotary table, drill pipes, drill collars and drill bit) is considered. The Karnopp friction model is adopted to simulate the nonlinear bit-rock interaction phenomena. In order to provide a more accurate evaluation, the proposed drill string controller is implemented with the induction motor, a variable frequency drive and a gearbox to closely mirror the real environment of oil well drill strings. The increasing demand for prototyping and testing high-power plants in realistic and safe environments has led to the advancement of new types of experimental investigations without hurting the real system or building a small-scale prototype for testing. The dynamic performance of the proposed controller has been investigated with MATLAB software as well as in a novel hardware in-the-loop (HIL) testing platform. A power plant is modeled and implemented in the real-time simulator OPAL-RT 5600, whereas the controllers are implemented in the dSPACE 1103 control board. The results obtained through simulation and HIL testing demonstrate the feasibility and high performance of the proposed controller.

Study of stick–slip suppression and robustness to parametric uncertainty in drill strings containing torsional vibration tool using sliding-mode control

2021 ◽  
pp. 146441932110452
Author(s):  
Jialin Tian ◽  
Jie Wang ◽  
Siqi Zhou ◽  
Yinglin Yang ◽  
Liming Dai
Keyword(s):  
Torsional Vibration ◽  
Complex Dynamics ◽  
Sliding Mode ◽  
Parametric Uncertainty ◽  
Drill String ◽  
Lumped Parameter Model ◽  
Drilling Process ◽  
Drill Bit ◽  
Stick Slip ◽  
Drilling Operations

Excessive stick–slip vibration of drill strings can cause inefficiency and unsafety of drilling operations. To suppress the stick–slip vibration that occurred during the downhole drilling process, a drill string torsional vibration system considering the torsional vibration tool has been proposed on the basis of the 4-degree of freedom lumped-parameter model. In the design of the model, the tool is approximated by a simple torsional pendulum that brings impact torque to the drill bit. Furthermore, two sliding mode controllers, U1 and U2, are used to suppress stick–slip vibrations while enabling the drill bit to track the desired angular velocity. Aiming at parameter uncertainty and system instability in the drilling operations, a parameter adaptation law is added to the sliding mode controller U2. Finally, the suppression effects of stick–slip and robustness of parametric uncertainty about the two proposed controllers are demonstrated and compared by simulation and field test results. This paper provides a reference for the suppression of stick–slip vibration and the further study of the complex dynamics of the drill string.

Vibration and Analysis of Multi-Disk Friction Systems

1998 ◽  
Author(s):  
Henric Larsson ◽  
Kambiz Farhang
Keyword(s):  
Frictional Contact ◽  
Vibration Characteristics ◽  
Lumped Parameter Model ◽  
Stick Slip ◽  
Friction Forces ◽  
Lumped Parameter ◽  
Modes Of Vibration ◽  
The Coefficient Of Friction ◽  
Slip Region ◽  
Stiffness And Damping

Abstract The paper presents a lumped parameter model of multiple disks in frictional contact. The contact elastic and dissipative characteristics are represented by equivalent stiffness and damping parameters in the axial as well as the torsional directions. The formulation accounts for the coupling betwen the axial and angular motions by viewing the contact normal force to be the result of axial behavior of the system. The frictional contact of two disks in contact is modeled in two dynamic states (i.e. sticking and slipping state) having individual lumped parameter models and the conditions that control the switching between the two states are established. The friction forces are represented by assuming the coefficient of friction to be a function of the sliding velocity, varying exponentially from its static value at zero relative velocity to its kinetic value at high velocities. A computer simulation of an eight-rotor disk assembly is presented. The torsional vibration characteristics and how it is liked to the axial modes of vibration is analyzed. The vibration characteristics in the transient, steady-state and stick-slip region is compared. In the stick-slip region, the angular velocity of the interfaces in frictional contact is depicted and the sticking and slipping states are defined. It is shown that the duration of slip is approximately constant and the duration of stick increases almost exponentially until a final sticking is achieved.

scholarly journals Reducing Lateral Vibrations of a Rotor Passing Through Critical Speeds by Acceleration Scheduling

1997 ◽  
Author(s):  
Knox T. Millsaps ◽  
Gregory L. Reed
Keyword(s):  
Critical Speed ◽  
Vibrational Energy ◽  
Lumped Parameter Model ◽  
Integration Scheme ◽  
Lateral Vibrations ◽  
Acceleration Rate ◽  
Lumped Parameter ◽  
Numerical Integration Scheme ◽  
Single Disk ◽  
Acceleration And Deceleration

A method is presented for reducing the lateral response of an imbalanced rotor accelerating or decelerating through its first lateral bending critical speed by using a variable acceleration rate. A lumped parameter model along with a numerical integration scheme is used to simulate the response of a simply supported, single disk rotor during fast acceleration and deceleration through critical speed. The results indicate that the maximum response and/or the total vibrational energy of a rotor passing through the critical speed can be reduced significantly by using a variable acceleration schedule. That is, reducing the acceleration rate after the nominal critical speed is passed. These predictions were verified experimentally for a single disk rotor.

Investigation on friction-induced judder of vehicle driveline based on a nonlinear friction model

2021 ◽  
pp. 095440702110632
Author(s):  
Shili Chang ◽  
Yuanfeng Xia ◽  
Jian Pang ◽  
Liang Yang
Keyword(s):  
Front Wheel ◽  
Friction Model ◽  
Friction Torque ◽  
The Self ◽  
Lumped Parameter Model ◽  
Torsional Stiffness ◽  
Vehicle Body ◽  
Nonlinear Friction ◽  
Stick Slip ◽  
Friction Element

Due to friction characteristics of clutch, the driveline is prone to cause a judder during vehicle starting, and then to cause the vehicle body to vibrate, which affects driving quality. In order to analyze the judder phenomenon, a nonlinear numerical friction model based on the Gaussian friction model is established in this paper. For the driveline of a front-wheel-drive vehicle, a five-degree-of-freedom (5DOF) lumped parameter model including a nonlinear friction element is established. The complex mode of the driveline during the clutch in slip condition is calculated. The key parameters affecting the driveline stability are analyzed. The self-excited judder and pressure-induced judder of the driveline are numerically simulated, and the corresponding causes are analyzed. The nonlinear friction torque of the clutch is also calculated. Furthermore, the effects of the key parameters such as the torsional stiffness and damping of the clutch and drive shaft suppressing the self-excited judder and pressure-induced judder are numerically studied respectively. Compared with the widely used Karnopp friction model, the nonlinear numerical friction model established in this paper comprehensively includes the stribeck effect in slip and the friction torque characteristics in stick. The phenomena of the judder and stick-slip of the driveline during vehicle starting are more accurately simulated. The simulation results are in good agreement with the experimental results, which verify the accuracy and effectiveness of the dynamic model including the nonlinear friction element established in this paper.

scholarly journals Vibrational Interaction of Two Rotors with Friction Coupling

2016 ◽  
Vol 2016 ◽  
pp. 1-9
Author(s):  
H. Larsson ◽  
K. Farhang
Keyword(s):  
Lumped Parameter Model ◽  
Equivalent Stiffness ◽  
Stick Slip ◽  
Lumped Parameter ◽  
Disk Friction ◽  
Axial Behavior ◽  
Stiffness And Damping Coefficient ◽  
Stiffness And Damping ◽  
Two Parameter ◽  
Very High

A lumped parameter model is presented for studying the dynamic interaction between two disks in relative rotational motion and in friction contact. The contact elastic and dissipative characteristics are represented by equivalent stiffness and damping coefficient in the axial as well as torsional direction. The formulation accounts for the coupling between the axial and angular motions by viewing the contact normal force a result of axial behavior of the system. The model is used to investigate stick-slip behavior of a two-disk friction system. In this effort the friction coefficient is represented as an exponentially decaying function of relative angular velocity, varying from its static value at zero relative velocity to its kinetic value at very high velocities. This investigation results in the establishment of critical curve defining two-parameter regions: one in which stick-slip occurs and that in which stick-slip does not occur. Moreover, the onset and termination of stick-slip, when it occurs, are related to the highest component frequency in the system. It is found that stick-slip starts at a period nearly equal to that of the highest component frequency and terminates at a period almost three times that of the highest component frequency.

Reducing Lateral Vibrations of a Rotor Passing Through Critical Speeds by Acceleration Scheduling

1998 ◽  
Vol 120 (3) ◽  
pp. 615-620 ◽  
Author(s):  
K. T. Millsaps ◽  
G. L. Reed
Keyword(s):  
Critical Speed ◽  
Vibrational Energy ◽  
Lumped Parameter Model ◽  
Integration Scheme ◽  
Lateral Vibrations ◽  
Acceleration Rate ◽  
Lumped Parameter ◽  
Numerical Integration Scheme ◽  
Single Disk ◽  
Acceleration And Deceleration

A method is presented for reducing the lateral response of an imbalanced rotor accelerating or decelerating through its first lateral bending critical speed by using a variable acceleration rate. A lumped parameter model along with a numerical integration scheme is used to simulate the response of a simply supported, single disk rotor during fast acceleration and deceleration through critical speed. The results indicate that the maximum response and/or the total vibrational energy of a rotor passing through the critical speed can be reduced significantly by using a variable acceleration schedule. That is, reducing the acceleration rate after the nominal critical speed is passed. These predictions were verified experimentally for a single disk rotor.

scholarly journals Simulation of Oil Well Drilling System Using Distributed–Lumped Modelling Technique

Modelling ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. 175-197
Author(s):  
Panagiotis Athanasiou ◽  
Yaser Hadi
Keyword(s):  
Oil And Gas ◽  
Long Strings ◽  
Lumped Parameter Model ◽  
Oil Well ◽  
Drilling Depth ◽  
Stick Slip ◽  
Well Drilling ◽  
Actual Measurement ◽  
Breakdown Time ◽  
Modelling Methodology

The strengths and torque of well-boiling hydrocarbons are of utmost significance. Boiling a well is one of the most critical steps in the discovery and production of oil and gas. The well’s boiling process is expensive because the drilling depth can be as much as 7000 meters. Any delay (breakdown time) in boiling costs a lot of money for hydrocarbon firms. Various boiler parameters are continuously tracked and regulated to avoid drilling delays. This paper focuses on the vibrations occurring at the bottom hole assembly (BHA) stick-slip. Two modelling methods, the lumped parameter model and the combination of the distributed–lumped (D–L) parameter model, were used and compared to the actual measurement performance. The D–L model was found to be more precise, particularly for long strings. Using the simulations, the most comprehensive modelling methodology is introduced.

scholarly journals Fractional-order controllers for stick-slip vibration mitigation in oil well drill-strings

2021 ◽  
pp. 146134842098404
Author(s):  
Massinissa Derbal ◽  
Mohamed Gharib ◽  
Shady S Refaat ◽  
Alan Palazzolo ◽  
Sadok Sassi
Keyword(s):  
Fractional Order ◽  
Degrees Of Freedom ◽  
Lumped Parameter Model ◽  
Oil Well ◽  
Proportional Integral Derivative ◽  
Stick Slip ◽  
Proportional Integral ◽  
Drilling Performance ◽  
Weight On Bit ◽  
Rotary Speed

Drillstring–borehole interaction can produce severely damaging vibrations. An example is stick–slip vibration, which negatively affects drilling performance, tool integrity and completion time, and costs. Attempts to mitigate stick–slip vibration typically use passive means and/or change the operation parameters, such as weight on bit and rotational speed. Automating the latter approach, by means of feedback control, holds the promise of quicker and more effective mitigation. The present work presents three separate fractional-order controllers for mitigating drillstring slip–stick vibrations. For the sake of illustration, the drillstring is represented by a torsional vibration lumped parameter model with four degrees of freedom, including parameter uncertainty. The robustness of these fractional-order controllers is compared with traditional proportional-integral-derivative controllers under variation of the weight on bit and the drill bit’s desired rotary speed. The results confirm the proposed controllers effectiveness and feasibility, with rapid time response and less overshoot than conventional proportional-integral-derivative controllers.

Investigation of Stick-Slip Phenomenon Using a Two-Disk Friction System Vibration Model

1997 ◽  
Author(s):  
Henric Larsson ◽  
Kambiz Farhang
Keyword(s):  
Normal Force ◽  
Lumped Parameter Model ◽  
Stick Slip ◽  
Lumped Parameter ◽  
Vibration Model ◽  
Disk Friction ◽  
System Vibration ◽  
Axial Behavior ◽  
Two Parameter ◽  
Very High

Abstract A lumped parameter model is presented for studying the dynamic interaction between two disks in relative rotational motion and in frictional contact. The contact elastic and dissipative characteristics are represented by equivalent stiffnesses and damping coefficients in the axial as well as torsional directions. The formulation accounts for the coupling between the axial and angular motions by viewing the contact normal force to be the result of axial behavior of the system. The model is used to investigate stick-slip behavior of a two-disk friction system. In this effort the friction coefficient is represented as an exponentially decaying function of relative angular velocity, varying from its static value at zero relative velocity to its kinetic value at very high velocities. This investigation result in establishment of critical curve defining two parameter regions: one in which stick-slip occurs and that in which stick-slip does not occur. Moreover, the onset and termination of stick-slip, when it occurs, is related to the highest component frequency in the system. It is found that stick-slip starts at a period nearly equal to that of the highest component frequency and terminates at a period almost three times that of the highest component frequency.

Sign in / Sign up

Export Citation Format

Share Document