Minimising Torsional Vibration Due to Stick Slip Using Z Technology for Drilling Energy Efficiency in Multiple Hard Stringers Field in Offshore Malaysia

2021 ◽  
Author(s):  
Mohamad Haikal Nordin ◽  
Lai Keng Looi ◽  
Pete Slagel ◽  
Mohamad Hafiz Othman ◽  
Abdul Razak Affandi ◽  
...  
Keyword(s):  
Torsional Vibration ◽  
Drill Pipe ◽  
Cost Savings ◽  
Wide Band ◽  
Static Friction ◽  
Drill String ◽  
Drill Bit ◽  
Stick Slip ◽  
Pull Out ◽  
Phase 1B

Abstract Field T is well known with its multiple layers of hard stringers that can go up to 25 ksi UCS at certain intervals, predominantly in 12-1/4" and 8-1/2" hole section. This can lead to stick-slip problem whereby the drill bit momentarily stalls due to high static friction, while the drill string keeps rotating. As a result, torque will buildup in pipe until it overcomes the friction at the bit, resulting in the drill pipe unwinding itself. Over time, this issue results in reduced drilling efficiency (i.e. lower ROP), eventually causing damage to the bit or worse, twisting off the BHA, which translates into high cost exposure to the Operator. During the exploration phase, the Operator required on average, 4 to 7 bit trips to drill 12-1/4" hole section and 2 to 4 trips were required to drill 8-1/2" hole section. The most reported reason to pull out of the hole were, BHA change out, downhole tool failure (DTF) and low rate of penetration (ROP). The bits’ inner & outer cutters were also reported to be damaged with dull grading as high as wear value of 7 or 8. Z technology is a torsional vibration mitigation system that uses wide band impedance (Z) matching concept that aims to absorb all torque waves arriving at top drive by overcoming inertia of motor & gearbox. The Z Technology changes the conventional hard boundary condition of a standard top drive (TD) RPM controller that is "stiff" (constant RPM) which results in full reflection of all torsional waves. A "stiff" TD control system leads to growth of standing waves (A combination of TD constant RPM & stick-slip "unwind" RPM) in the string which eventually may lead to torsional vibrations to the drill bit and/or motor housing/BHA. While drilling Development Phase 1B, Z Technology was seen to be effective in mitigating stick-slip. As a result, more mechanical specific energy (MSE) was available to be transmitted to the bit for formation rock removal. All three wells in the Phase 1B campaign managed to achieve the highest ROP in T field. This translated into cost savings in rig time and cost avoidance to Operator due to BHA damage. The paper will discuss the details of the Z Technology mechanism, its implementation and evaluating its effectiveness in minimizing torsional vibration due to the stick-slip issue.

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.

Torsional Vibrations and Nonlinear Dynamic Characteristics of Drill Strings and Stick-Slip Reduction Mechanism

2019 ◽  
Vol 14 (8) ◽  
Author(s):  
Jialin Tian ◽  
Genyin Li ◽  
Liming Dai ◽  
Lin Yang ◽  
Hongzhi He ◽  
...  
Keyword(s):  
Torsional Vibration ◽  
Nonlinear Dynamic ◽  
Drill String ◽  
Drilling Process ◽  
Drill Bit ◽  
Torsional Vibrations ◽  
Reduction Mechanism ◽  
Nonlinear Dynamic Model ◽  
Stick Slip ◽  
Research Results

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.

scholarly journals Drillstring Failure: Analytical and Experimental Approach

2019 ◽  
Vol 300 ◽  
pp. 04004
Author(s):  
Edris Hassan ◽  
Jamil Abdo ◽  
Jan Kwak ◽  
Abdullah Al Shabibi
Keyword(s):  
Torsional Vibration ◽  
Oil And Gas ◽  
Drill Pipe ◽  
Oil And Gas Industry ◽  
Drill String ◽  
Design Parameters ◽  
Experimental Investigations ◽  
Torsional Vibrations ◽  
Stick Slip ◽  
The Impact

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.

Experimental Investigation of the Stick-Slip Phenomena of the Drill Pipe

2015 ◽  
Author(s):  
Tokihiro Katsui ◽  
Yoshitomo Mogi ◽  
Tomoya Inoue ◽  
Chang-Kyu Rheem ◽  
Miki Y. Matsuo
Keyword(s):  
Drill Pipe ◽  
Small Time ◽  
Numerical Results ◽  
Experimental Results ◽  
Frictional Torque ◽  
Drill Bit ◽  
Stick Slip ◽  
Model Experiments ◽  
Pipe Model ◽  
Weight On Bit

The stick-slip is one of the critical problems for the scientific drilling, because it causes a crushing of the sampled layer. The present study investigates the characteristics of stick-slip phenomena of the drill pipe with the model experiments and numerical methods. The model experiments are carried out using a 1m length drill pipe model made with the Teflon. The angular velocity at the top and the bottom of the pipe are measured with the gyro sensor on some conditions of rotating speed at the pipe top and the weight on bit (load at the pipe bottom). The numerical simulations are also carried out to reproduce the stick-slip phenomena of the model experiments. The stick-slip is a kind of torsional vibration which is governed by the convection equation. By considering the boundary condition at the top and bottom of the pipe, we can obtain a neutral delayed differential equation (NDDE). The solutions of the NDDE is depend on not the initial value but the initial history of the solution, because NDDE contains a delayed function term. Therefore, it should be solved carefully to avoid the numerical error. The NDDE is solved with the 4th order Runge-Kutta scheme with very small time increment until the truncation error could be neglected. And also, we have found out that the effect of the initial history on the solution become to be very small after a certain period of time. The experimental results are compared with the numerical results under the same rotating condition. The experimental results of the stick-slip suggest that the period of the slip is mainly depend on the rotation speed at the pipe top and the magnitude of the slip is mainly depend on the weight on bit. Those characteristics of the stick-slip such as the period or the magnitude of slip are also obtained with the numerical calculations. However, in order to obtain an acceptable numerical results of NDDE, we have to adjust the frictional torque acting on the drill bit. Though, the frictional torque model was determined by reference to the measured torque at the top of the drill pipe model in the present study, it is desired to be improved. Therefore, the physical model of the frictional torque on the drill bit should be evaluated much carefully for the precise estimation of the stick slip in the future.

Analysis of stick-slip reduction for a new torsional vibration tool based on PID control

2019 ◽  
Vol 234 (1) ◽  
pp. 82-94 ◽  
Author(s):  
Jialin Tian ◽  
Yi Zhou ◽  
Lin Yang ◽  
Shuhui Hu
Keyword(s):  
Torsional Vibration ◽  
Pid Control ◽  
Control Method ◽  
Field Tests ◽  
Rock Breaking ◽  
Drill String ◽  
Viscosity Reduction ◽  
Stick Slip ◽  
Deep Wells ◽  
Reduction Characteristics

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.

scholarly journals Numerical Application of a Stick-Slip Control and Experimental Analysis using a Test Rig

2018 ◽  
Vol 148 ◽  
pp. 16009 ◽  
Author(s):  
Leonardo D. Pereira ◽  
Bruno Cayres ◽  
Hans I. Weber
Keyword(s):  
Deep Water ◽  
Torsional Vibration ◽  
Oil And Gas ◽  
Dynamical Behaviour ◽  
Drill String ◽  
Oil Field ◽  
Test Rig ◽  
Numerical Application ◽  
Stick Slip ◽  
Lateral Vibrations

Part of the process of exploration and development of an oil field consists of the drilling operations for oil and gas wells. Particularly for deep water and ultra deep water wells, the operation requires the control of a very flexible structure which is subjected to complex boundary conditions such as the nonlinear interactions between drill bit and rock formation and between the drill string and borehole wall. Concerning this complexity, the stick-slip phenomenon is a major component related to the torsional vibration and it can excite both axial and lateral vibrations. With these intentions, this paper has the main goal of confronting the torsional vibration problem over a test rig numerical model using a real-time conventional controller. The system contains two discs in which dry friction torques are applied. Therefore, the dynamical behaviour were analysed with and without controlling strategies.

Measurement of Mud Motor Back-Drive Dynamics, Associated Risks and Benefits of Real-Time Detection and Mitigation Measures

2021 ◽  
Author(s):  
Junichi Sugiura ◽  
Steve Jones
Keyword(s):  
Pressure Sensors ◽  
Drill String ◽  
Sensor Data ◽  
Depth Interval ◽  
Drill Bit ◽  
Motor Power ◽  
Stick Slip ◽  
Rate Of Penetration ◽  
The Past ◽  
Drive Dynamics

Abstract North America shale drilling is a fast-paced environment where downhole drilling equipment is pushed to the limits for maximum rate of penetration (ROP). Downhole mud motor power sections have rapidly advanced to deliver more horsepower and torque, resulting in different downhole dynamics that have not been identified in the past. High-frequency (HF) compact drilling dynamics recorders embedded in the drill bit, mud-motor bit box, and motor top sub (sub-assembly) provide unique measurements to fully understand the reaction of the steerable-motor power section under load relative to the type of rock being drilled. 3-axis shock, gyro and temperature sensors placed above and below the power section measure the dynamic response of power transfer to the bit and associated losses caused by back-drive dynamics. Detection of back-drive from surface measurements is not possible, and many measurement-while-drilling (MWD) systems do not have the measurement capability to identify the problem. Motor back-drive dynamics severity is dependent on many factors, including formation type, bit type, power section, WOB (weight on bit) and drill pipe size. The torsional energy stored and released in the drill string can be high due to the interaction between surface RPM (revolutions per minute)/torque output and mud-motor downhole RPM/torque. Torsional drill string energy wind-up and release results in variable power output at the bit, inconsistent rate of penetration (ROP), rapid fatigue on downhole equipment, and motor or drillstring back-offs and twist-offs. A new mechanism of motor back-drive dynamics due to the use of an MWD pulser above a steerable motor is discovered. HF continuous gyro sensors and pressure sensors were deployed to capture the mechanism in which a positive mud pulser reduces as much as one third of the mud flow in the motor and bit rotation speed, creating a propensity for a bit to come to a complete stop in certain conditions and for the motor to rotate the drillstring backward. We have observed the backward rotation of a PDC drill bit during severe stick-slip and back-drive events (-50 RPM above the motor), confirming that the bit rotated backward for 9 mS every 133.3 mS (at 7.5Hz), using a 1000-Hz continuous sampling/recording in-bit gyro. In one field test, multiple drillstring dynamics recorders were used to measure the motor back-drive severity along the drillstring. It is discovered that the back-drive dynamics are worse at the drillstring, approximately 1110 ft behind the bit, than these measured at the motor top-sub position. These dynamics caused drillstring back-offs and twist-offs in a particular field. A motor back-drive mitigation tool was used in the field to compare the runs with and without the mitigation tool, while keeping the surface drilling parameters nearly the same. The downhole drilling dynamics sensors were used to confirm that the mitigation tool significantly reduced stick-slip and eliminated the motor back-drive dynamics in the same depth interval. Detailed analysis of the HF embedded downhole sensor data provides an in-depth understanding of mud-motor back-drive dynamics. The cause, severity, reduction in drilling performance and risk of incident can be identified, allowing performance and cost gains to be realized. This paper will detail the advantages to understanding and reducing motor back-drive dynamics, a topic that has not commonly been discussed in the past.

The Characteristics of Numerical Solution of NDDE to Solve the Drill Pipe Stick-Slip

2019 ◽  
Author(s):  
Tokihiro Katsui ◽  
Tomoya Inoue ◽  
Daisuke Sogawa ◽  
Yusuke Notani
Keyword(s):  
Numerical Model ◽  
Numerical Solutions ◽  
Drill Pipe ◽  
Frictional Torque ◽  
Model Parameters ◽  
Drill Bit ◽  
Neutral Delay ◽  
Stick Slip ◽  
Scientific Drilling ◽  
Pipe Model

Abstract The Stick-Slip is one of troublesome problems which happens in scientific drilling. In order to clarify the mechanism of Stick-Slip phenomenon, it is necessary to develop a reliable numerical model [1]-[4] to estimate drill bit motion for various drilling conditions. We have investigated on an NDDE (Neutral Delay Differential Equation) [5] to solve Stick-Slip of drill pipe [6]-[8]. In order to solve this NDDE, it is necessary to determine the frictional torque acting on the drill bit. In the previous study, we have employed the Balanov’s [4] frictional torque model which is the function of drill bit rotation with four unknown model parameters. This numerical model calculates the Stick-Slip phenomena of the drill pipe model in the laboratory experiments correctly under the appropriate four model parameter settings. On the other hand, it is quite difficult to calculate the actual drill pipe Stick-Slip [9], because the calculated results change drastically depending on the four unknown parameter settings. In the present study, the frictional torque acting on the drill bit is defined as a periodic function and solved the NDDE to calculate the stick-slip of the actual drill pipe. The average, variation and period of the frictional torque on the drill bit were set under the consideration of measured top drive torques. The calculated numerical solutions of the drill bit motion and the top drive torque agreed qualitatively with the measured ones.

scholarly journals Complex dynamics of drill-strings: Theory and experiments

2018 ◽  
Vol 211 ◽  
pp. 01002
Author(s):  
Marian Wiercigroch ◽  
Marcin Kapitaniak ◽  
Vahid Vaziri ◽  
Krishnan Nandakumar
Keyword(s):  
Mechanical Characteristics ◽  
Complex Dynamics ◽  
Drill String ◽  
Drill Bit ◽  
Stick Slip ◽  
Drill Bits ◽  
Low Dimensional ◽  
The University ◽  
Experimental Rig ◽  
Theory And Experiments

We investigate complex drill-string dynamics in a downhole drilling where strong nonlinear interactions between various types of vibration take place. First, we present a low dimensional model of the downhole drilling where a drill-bit cutting a rock formation has a strong coupling between torsional and axial oscillations. The model can be used to study drilling stability as an example results are given. Then we introduce a new experimental rig developed by the Centre for Applied Dynamics Research at the University of Aberdeen, capable of reproducing all major types of drill-string vibration. One of the most important features of this versatile experimental rig is the fact that commercial drill-bits, employed in the drilling industry, and real rock-samples are used. The rig operate in different configurations, which enables the experimental study of various phenomena, such as stick-slip oscillations, whirling and drill-bit bounce. It also allows to determine mechanical characteristics of the drill-bits, which are used to calibrate mathematical models.

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