scholarly journals MINIMIZING DRILL STRING TORSIONAL VIBRATION USING SURFACE ACTIVE CONTROL

Author(s):  
LEONARDO DIAS PEREIRA
Author(s):  
Jialin Tian ◽  
Jie Wang ◽  
Siqi Zhou ◽  
Yinglin Yang ◽  
Liming Dai

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.


Author(s):  
Jialin Tian ◽  
Genyin Li ◽  
Liming Dai ◽  
Lin Yang ◽  
Hongzhi He ◽  
...  

Torsional stick–slip vibrations easily occur when the drill bit encounters a hard or a hard-soft staggered formation during drilling process. Moreover, serious stick–slip vibrations of the drill string is the main factor leading to low drilling efficiency or even causing the downhole tools failure. Therefore, establishing the stick–slip theoretical model, which is more consistent with the actual field conditions, is the key point for new drilling technology. Based on this, a new torsional vibration tool is proposed in this paper, then the multidegree-of-freedom torsional vibrations model and nonlinear dynamic model of the drill string are established. Combined with the actual working conditions in the drilling process, the stick–slip reduction mechanism of the drill string is studied. The research results show that the higher rotational speed of the top drive, smaller viscous damping of the drill bit, and smaller WOB (weight on bit) will prevent the stick–slip vibration to happen. Moreover, the new torsional vibration tool has excellent stick–slip reduction effect. The research results and the model established in this paper can provide important references for reducing the stick–slip vibrations of the drill string and improving the rock-breaking efficiency.


2018 ◽  
Vol 9 (1) ◽  
pp. 34 ◽  
Author(s):  
Biqing Zhong ◽  
Bin Deng ◽  
Han Zhao

Hybrid electric vehicles (HEV) might cause new noise vibration and harshness (NVH) problems, due to their complex powertrain systems. Therefore, in this paper, a new longitudinal dynamic simulation model of a series-parallel hybrid electric bus with an active torsional vibration control module is proposed. First, the schematic diagrams of the simulation model architecture and the active control strategy are given, and the dynamic models of the main components are introduced. Second, taking advantage of the characteristics of hybrid systems, a method of determining the key dynamic parameters by a bench test is proposed. Finally, in a typical bus-driving cycle for Chinese urban conditions, time domain and frequency domain processing methods are used to analyze vehicle body jerk, fluctuation of rotational speed, and torsional angle of the key components. The results show that the active control method can greatly improve the system’s torsional vibration performance when switching modes and at resonance.


Author(s):  
William H. Cuellar ◽  
Eugenio Fortaleza

A hydropneumatic heave compensation system and a semi-active control are proposed according to the requirements drilling offshore of 6 km deep. The goal of this semi-active control is to maintain an acceptable performance of the system when the drill string mass changes, which also changes the performance of the hydropneumatic system. The control action is executed just by a servo valve, which modifies the system damping to optimize the compensator performance. This servo valve is the only moving part of the control system and therefore, this system is more robust regarding mechanical/ electrical failures and it has low consumption energy. The results show a satisfactory frequency response of semi-active control when the drill string mass is changed.


Author(s):  
Ying Huang ◽  
Yongguang Yang ◽  
Fujun Zhang ◽  
Zhenfeng Zhao

The torsional vibration of a crankshaft greatly affects engine performance, and the control and suppression of such vibration have thus always been a focus of engine research. The introduction of an electronic fuel-injection system for the diesel engine has made it possible to control individual cylinders, thus providing a new way to actively control the torsional vibration of a diesel engine. A V8 diesel engine model for co-simulation between crankshaft dynamics and engine performance was established with GT-SUIT software, and the model was verified by experiment data. The active control of crankshaft torsional vibration of a diesel engine by adjusting the fuel injection vector was simulated. First, the amplitude–frequency and phase–frequency characteristics of the excitation torque under different fuel-injection-vector conditions were analyzed. On the basis of the frequency characteristics, different active vibration-suppression schemes were studied, and the crankshaft vibration suppression effects were compared. The simulation results show that adjusting the fuel injection vector is an effective approach for controlling the torsional vibration of an engine crankshaft.


Author(s):  
Jialin Tian ◽  
Yi Zhou ◽  
Lin Yang ◽  
Shuhui Hu

The phenomenon of stick-slip vibration is widespread in the exploration of deep and ultra-deep wells. It causes the reduction of the mechanical drilling rate and wastes the driving energy. Besides, it also accelerates the aging and failure of the drill strings and threatens the safety of drilling seriously. In order to effectively control the stick-slip vibration of the drill string, a new type of torsional vibration tool is proposed in this paper firstly. Then, the theoretical model of the drill string system based on the tool is established. And then, the viscosity reduction characteristics of the new torsional vibration tool are studied by the PID control method. Finally, field tests were carried out in comparison with simulation. The results show that the new torsional vibration tool can reduce the stick-slip vibration. And the two PID control equations can both control the drill bit speed in real time through changing the turntable speed. The results also have important reference significance for reducing and controlling the stick-slip vibration of the drill string and improving the rock-breaking efficiency.


2019 ◽  
Vol 300 ◽  
pp. 04004
Author(s):  
Edris Hassan ◽  
Jamil Abdo ◽  
Jan Kwak ◽  
Abdullah Al Shabibi

Drilling is one of the costliest activities in oil and gas industry due to the complexity of interactions with downhole rock formation. Under such conditions, the uncertainty of drillstring behaviour increase and hence it becomes difficult to predict the causes, occurrences, and types of failures. Lateral and torsional vibrations often cause failure of Bottom Hole Assembly (BHA), drillstring failure, drill bit and wall borehole damages. In this work, a model is presented to determine the impact of lateral and torsional vibrations on a drillstring during the drilling operation. The model aims to mimic real drillstring behaviour inside a wellbore with regards to its dynamic movements due to multiple real situations such as eccentricity of collars, drill pipe sections, and stick-slip phenomena occurring due to the interaction of the bit and the drillstring with the well formation. The work aims to develop a basis for determining critical operating speeds and design parameters to provide safe drilling procedures and reduce drill string fatigue failure. Lagrangian approach is used in this study to attain drillstring lateral and torsional vibration coupling equations. The nonlinear equations are solved numerically to obtain the response of the system. In this work, we also present a brief description of an in-house constructed experimental setup. The setup has the capability to imitate the downhole lateral and torsional vibration modes. Parameters from the experimental investigations are incorporated for validation of the mathematical models and for prediction of the drillstring fatigue life. Such investigations are essential for oil and gas industries as they provide solutions and recommendations about operational speed, lateral and torsional amplitudes measurements and corrections, and the conditions for avoiding occurrence of natural frequencies of the system.


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