Nonlinear Model for Dynamic Behavior of Drill-String

2002 ◽  
Author(s):  
Hayat Melakhessou ◽  
Alain Berlioz ◽  
Guy Ferraris
Keyword(s):  
Dynamic Behavior ◽  
Degrees Of Freedom ◽  
Initial Position ◽  
Drill String ◽  
Lagrange Equations ◽  
Bottom Hole Assembly ◽  
Drilling Operations ◽  
Set Up ◽  
Mean Time ◽  
Drill Collar

This article is devoted to the study of the contact between the drill-string and the well during drilling operations. The study focuses on the Bottom-Hole-Assembly (BHA), which is submitted to compression. The work is motivated by the need to understand the complex behavior of such a system, in order to improve control their constructive and destructive potentials. The contact, which is supposed to be localized on the drill-collar or stabilizers, is prejudicial and involves a premature abrasive wear of the drill-string, reduction of the rate of penetration of the tool into the rock (ROP) and reduction of the mean time between failure (MTBF). The proposed mathematical model is expressed in terms of four independent degrees of freedom. They include the effects of bending and torsion; the whirling motion of the drill-string as well as the phenomena of friction between the drill-string and the well. The tangential effect is modeled by using Coulomb’s law of friction. The nonlinear equations of the movement are derived using Lagrange equations and are solved numerically to obtain the response. Specific attention is paid to the study of friction and a consistent contact model which is capable of taking into account the rolling of the drill-string, both with and without slip, is included in the model. This paper also presents a parametric study on the influence of the initial position of the string and the friction coefficient of the contact on the dynamic behavior of the structure. An experimental set-up, equipped with two optolineic devices, is used to validate the model.

A Nonlinear Well-Drillstring Interaction Model

2003 ◽  
Vol 125 (1) ◽  
pp. 46-52 ◽  
Author(s):  
Hayat Melakhessou ◽  
Alain Berlioz ◽  
Guy Ferraris
Keyword(s):  
Degrees Of Freedom ◽  
Interaction Model ◽  
Element Model ◽  
Tangential Direction ◽  
Initial Position ◽  
Lagrange Equations ◽  
Bottom Hole Assembly ◽  
Drilling Operations ◽  
Set Up ◽  
Mean Time

This article is devoted to the study of the local contact between the drillstring and the well during drilling operations. The study focuses on the Bottom-Hole-Assembly (BHA), which is subjected to compression. The work is motivated by the need to understand the complex behavior of such a system, in order to improve control over their constructive and destructive potentials. The contact zone is first determined using a global finite-element model obtained from a specific computer program. Contact, which is assumed to be located somewhere on the drill-collar or on stabilizers, is prejudicial and leads to premature abrasive wear of the drillstring, reduction of the Rate Of Penetration (ROP) of the tool into the rock and reduction of the Mean Time Between Failure (MTBF). The proposed mathematical model is expressed in terms of four independent degrees of freedom which are radial displacement, rotation of the section considered, bending along the tangential direction and torsion of the string. They include the effects of bending and torsion, the whirling motion of the drillstring as well as friction phenomena occurring between the drillstring and the well. The tangential effect is modeled by using Coulomb’s law of friction. The nonlinear equations of movement are derived using Lagrange equations and are solved numerically to obtain the response. Specific attention is paid to the study of friction and a consistent contact model capable of taking into account the rolling of the drillstring, both with and without slip, is included in the model. This paper also presents a parametric study on the influence of the initial position of the string and the friction coefficient of the contact on the dynamic behavior of the structure. The model is validated by an experimental set-up equipped with two opto-electronic devices.

scholarly journals Modeling and Control of an Active Stabilizing Assistant System for a Bicycle

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 248 ◽  
Author(s):  
Chih-Keng Chen ◽  
Trung-Dung Chu ◽  
Xiao-Dong Zhang
Keyword(s):  
Dynamic Behavior ◽  
Degrees Of Freedom ◽  
Rear Seat ◽  
System Dynamic ◽  
Lagrange Equations ◽  
Modeling And Control ◽  
Control Actions ◽  
Bicycle Rider ◽  
Study Designs ◽  
And Control

This study designs and controls an active stabilizing assistant system (ASAS) for a bicycle. Using the gyroscopic effect of two spinning flywheels, the ASAS generates torques that assist the rider to stabilize the bicycle in various riding modes. Riding performance and the rider’s safety are improved. To simulate the system dynamic behavior, a model of a bicycle–rider system with the ASAS on the rear seat is developed. This model has 14 degrees of freedom and is derived using Lagrange equations. In order to evaluate the efficacy of the ASAS in interacting with the rider’s control actions, simulations of the bicycle–rider system with the ASAS are conducted. The results for the same rider for the bicycle with an ASAS and on a traditional bicycle are compared for various riding conditions. In three cases of simulation for different riding conditions, the bicycle with the proposed ASAS handles better, with fewer control actions being required than for a traditional bicycle.

scholarly journals Studying of speed on the process drill string flattening vertical wells

2019 ◽  
pp. 30-38
Author(s):  
Rasul M. Aliyev ◽  
Shamil M. Kurbanov ◽  
Temirlan M. Umariev
Keyword(s):  
Drill String ◽  
Oil Field ◽  
Vertical Wells ◽  
Service Companies ◽  
Field Service ◽  
Bottom Hole ◽  
Geological Conditions ◽  
Bottom Hole Assembly ◽  
The Cost ◽  
Drill Collar

The issue of vertical wells curvature is important, especially when conducting wells in complex geological conditions of drilling, due to the increasing depth of the wells and the corresponding rise in the cost of drilling. The cause of this circumstance lies in the large time and financial costs while flattening of the bent wells. Moreover, it should be noted that during the subsequent drilling of a curved well the risk of key-seating and the corresponding complications increases. That is why large oil field service companies and drilling enterprises are paying more and more attention to solving the problem of vertical wells curvature. This article is devoted to investigation the effect of rotation of the drill string on the deflecting force on the bit while drilling a vertical well in a rotary way. We suggest using of eccentric drill collars for drilling vertical wells in difficult geological conditions. Also, we create an expression for the dynamic milling force on the bit, taking into account the usage of an eccentric drill collar in the composition of bottom-hole assembly.

Improved Drilling Operations with Wired Drill Pipe and Along-String Measurements – Learnings and Highlights from Multiple North Sea Deployments

2021 ◽  
Author(s):  
Børge Engdal Nygård ◽  
Espen Andreassen ◽  
Jørn Andre Carlsen ◽  
Gunn Åshild Ulfsnes ◽  
Steinar Øksenvåg ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Real Time ◽  
High Speed ◽  
Drill Pipe ◽  
Large Data ◽  
Drill String ◽  
Bottom Hole Assembly ◽  
Drilling Operations ◽  
Downhole Measurements ◽  
Remote Operations

Abstract Over the last few years, multiple wells have been drilled in the Norwegian Continental Shelf (NCS) and the United Kingdom Continental Shelf (UKCS) using wired drill pipe (WDP). This paper captures highlights from using real-time downhole measurements provided by WDP, for improved drilling operations. It presents learnings on how WDP measurements have been used in the operator's decision process. As part of WDP, along-string measurement subs (ASM) are equipped with temperature, annular/internal pressure, rotation and vibrations sensors. Data is transmitted to surface at high speed and is available in real-time, even when flow is off. The data provide great insight into the hole conditions along the drill string and at the bottom hole assembly (BHA). Based on this insight, drilling parameters at surface can be accurately adjusted, resulting in increased overall efficiency. Large data amounts can be communicated to and from surface with negligible time delay and independent from fluid circulation. Displaying the downhole measurements in real-time, both at the rig site and in remote operations centers has proven essential when optimising well construction activities. All parties need to access the same information in real-time. Moreover, the data need to be presented in an intuitive manner that enable improved operational decisions. To maximize WDP values, the Operator has learned that downhole data must be used to adjust drilling operations in real-time.

Estimation of High-Frequency Vibration Loads in Deep Drilling Systems Using Augmented Kalman Filters

2020 ◽  
Author(s):  
Mohamed Ichaoui ◽  
Georg-Peter Ostermeyer ◽  
Mathias Tergeist ◽  
Andreas Hohl
Keyword(s):  
Kalman Filters ◽  
Dynamic Models ◽  
Mechanical Energy ◽  
Drill String ◽  
Connected Components ◽  
Deep Drilling ◽  
Geothermal Heat ◽  
Bottom Hole Assembly ◽  
Drilling Operations ◽  
Critical Components

Abstract Deep drilling operations are primarily used to produce oil, gas, and geothermal heat from reservoirs in the earth’s crust. A drill string built of thread-connected components is used to transfer mechanical energy from a drill rig on the surface to a drill bit at the bottom end. The lowest part of a drill string, which is called bottom-hole assembly (BHA), contains sophisticated sub-assemblies for process and trajectory control, formation evaluation, surface communication, power generation, and system diagnostics. The BHA can experience critical vibrations without indication further up to the string. These vibrations need to be closely monitored for process control, fatigue management, and design feedback. However, the number of sensors is too small to provide reliable indication of loads on all critical components of the drill string. Adding sensors to each component is currently neither economically nor technically viable. This paper presents an application of existing Kalman Filters, merging information from available sensors and dynamic models to obtain state estimates for all components of the BHA. The expected accuracy and limitations are discussed. The results of load extrapolation are confirmed by comparison with measurements proving the concept under inaccurately defined interaction with a downhole environment.

scholarly journals Kinematics and dynamics analysis of new rotary-percussive PDM drilling tool

2021 ◽  
pp. 146134842198915
Author(s):  
Jialin Tian ◽  
Xuehua Hu ◽  
Liming Dai ◽  
Lin Yang ◽  
Yi Yang ◽  
...  
Keyword(s):  
Drill String ◽  
Structure Design ◽  
Drilling Process ◽  
Analysis Model ◽  
Drilling Tool ◽  
Stick Slip ◽  
Rate Of Penetration ◽  
Bottom Hole ◽  
Bottom Hole Assembly ◽  
The Impact

This paper presents a new drilling tool with multidirectional and controllable vibrations for enhancing the drilling rate of penetration and reducing the wellbore friction in complex well structure. Based on the structure design, the working mechanism is analyzed in downhole conditions. Then, combined with the impact theory and the drilling process, the theoretical models including the various impact forces are established. Also, to study the downhole performance, the bottom hole assembly dynamics characteristics in new condition are discussed. Moreover, to study the influence of key parameters on the impact force, the parabolic effect of the tool and the rebound of the drill string were considered, and the kinematics and mechanical properties of the new tool under working conditions were calculated. For the importance of the roller as a vibration generator, the displacement trajectory of the roller under different rotating speed and weight on bit was compared and analyzed. The reliable and accuracy of the theoretical model were verified by comparing the calculation results and experimental test results. The results show that the new design can produce a continuous and stable periodic impact. By adjusting the design parameter matching to the working condition, the bottom hole assembly with the new tool can improve the rate of penetration and reduce the wellbore friction or drilling stick-slip with benign vibration. The analysis model can also be used for a similar method or design just by changing the relative parameters. The research and results can provide references for enhancing drilling efficiency and safe production.

scholarly journals Galloping Stability and Wind Tunnel Test of Iced Quad Bundled Conductors considering Wake Effect

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Xiaohui Liu ◽  
Ming Zou ◽  
Chuan Wu ◽  
Mengqi Cai ◽  
Guangyun Min ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Transmission Lines ◽  
Degrees Of Freedom ◽  
Wind Tunnel Test ◽  
Aerodynamic Coefficients ◽  
Wake Effect ◽  
Aerodynamic Coefficient ◽  
Set Up ◽  
The Stability ◽  
Three Degrees Of Freedom

A new quad bundle conductor galloping model considering wake effect is proposed to solve the problem of different aerodynamic coefficients of each subconductor of iced quad bundle conductor. Based on the quasistatic theory, a new 3-DOF (three degrees of freedom) galloping model of iced quad bundle conductors is established, which can accurately reflect the energy transfer and galloping of quad bundle conductor in three directions. After a series of formula derivations, the conductor stability judgment formula is obtained. In the wind tunnel test, according to the actual engineering situation, different variables are set up to accurately simulate the galloping of iced quad bundle conductor under the wind, and the aerodynamic coefficient is obtained. Finally, according to the stability judgment formula of this paper, calculate the critical wind speed of conductor galloping through programming. The dates of wind tunnel test and calculation in this paper can be used in the antigalloping design of transmission lines.

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.

LOWER LIMB REHABILITATION ROBOT FOR GAIT TRAINING

2014 ◽  
Vol 14 (06) ◽  
pp. 1440004 ◽  
Author(s):  
SHUAI GUO ◽  
JIANCHENG JI ◽  
GUANGWEI MA ◽  
TAO SONG ◽  
JING WANG
Keyword(s):  
Lower Limb ◽  
Degrees Of Freedom ◽  
Balance Training ◽  
Gait Training ◽  
Rehabilitation Robot ◽  
Stroke Patients ◽  
Motion Characteristics ◽  
Set Up ◽  
Limb Rehabilitation ◽  
Lower Limb Rehabilitation

After analyzing the rehabilitation needs of stroke patients and the previous studies on lower limb rehabilitation robot, our lower limb rehabilitation robot is designed for stroke patients' gait and balance training. The robot consists of the mobile chassis, the support column and the pelvis mechanism and it is described in detail. As the pelvis mechanism allows most of the patient's motion degrees of freedom (DOFs), the kinematics model of the mechanism is set up, and kinematics simulation is carried out to study the motion characteristics of the mechanism. After analyzing the calculation and simulation results, the pelvis mechanism is proven to measure up to the movement needs of the paralytic's waist and pelvis in walking rehabilitation process.

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