Extensive research on the subject of torsional vibrations has already been conducted leine, 2000. Our models range from complex to reduced models and down to minimal models with realtime. The shock tool allows optimum bit speed to be used under rough drilling conditions, increasing the rate of penetration. Drillstring vibrations and vibration modeling lateral vibrations are the most destructive type of vibration and can create large shocks as the bha impacts the wellbore wall. The rules of drill string vibration are obtained by the analysis on the vibration models. During exploitation of horizontal well drilling engineering, the problem of drill string failure is very serious, there are many reasons, and drill string vibrations are main reasons. S can limit the optimization of drilling performance, which is a key problem for trajectory optimizing, wellbore design, increasing drill tools life, rate of penetration, and intelligent drilling. Top panel shows a typical torsional vibration of the drill string, where the drill bit angular velocity varies with high amplitude around the angular velocity of the top of the drill pipe. Pdf failure of drillstrings is very costly in terms of money and time and occurs more frequently than oil companies would like to see. With significant reduction of vibrations transmitted from drill string to drill head, the need for drill head repairs decreases and also extends life of drill rig. Drillstring vibration analysis using nonsmooth dynamics. Citeseerx document details isaac councill, lee giles, pradeep teregowda.
The result of drillstring vibration is premature failure of the equipment and reduced. Drill collar dc selection there are two types of dc. In extreme cases of torsional oscillations, the drill bit can come to a standstill for a short period of time, resulting in stickslip as shown in. The drill pipe is acting as a torsional spring ks nmrad. Adams drill is a toolkit we developed to predict the dynamic behavior of a drill string, including any nonlinear and fully coupled axial, lateral and torsional responses to various sequences of surface control parameters. Pdf drill string vibration modeling including coupling effects. Torsional vibration such as stickslip vibration is considered to be one of the most common causes for drill string system failures. Increased rop with stickslip and auto driller technology saves wear and tear on bits, bha, drill string and top drive more gentle control of machines reduces maintenance key features minimize downhole vibration by controlling surface wob and rpm detects, prevents and mitigates stickslip. Modelling and analysis of bha and drillstring vibrations. According to drilling condition, the drill string vibration analysis model is presented as in figure 1 wherein denotes the location layer of th drill string, is the total length of the drill string, and, respectively, denote the outer and inner radius of th drill string,, respectively, denote the shear stress of drilling fluid inside and. The interaction between bha and drillstring contact points may, in certain circumstances. Slick dc spiral dc in areas where differential sticking is a possibility spiral dc should be used in order to minimize contact area with formation. An apparatus and method for damping vibration, especially torsional vibration due to stickslip, in a drill string, sensors measure the instantaneous angular velocity of the drill string at one or more locations along the length of the drill string. The solution to these challenges lies in utilizing surface measurements of torque, rpm, hookload and stand pipe pressure for vibration monitoring along the entire drill string.
Welldrill analytical software for downhole drilling equipment. A proxy for identifying lithologic boundaries while drilling article pdf available may 2002 with 76 reads how we measure reads. Results underreamed 24in pilot hole to 28 in with no shock and vibration or surface torque fluctuations. The control strategy which would minimize the vibrations affecting the drill string and stabilize it must ensure that the drill string is operated at a velocity away from its critical speeds of rotation. We are constantly updating our materials to reflect the latest technology applications for both nearvertical and highangle well designs while maintaining a thorough grounding in the fundamentals. The research project is aimed at developing an experimentally verified analytical model describing the vibrations of the bottom hole assembly bha and drillstring employed in oil and gas extraction. The second is a realtime system to monitor 3axis drillstring vibration, and related. Institute of dynamics and vibrations drill string dynamics group. The well is deviated from vertical direction by a constant but small angle in order to find the axial and torsional natural frequencies, the corresponding wave equations of the beam are solved using the entire.
The lower part of a drill string used for the drilling of oil or gas wells is usually composed of drill collars and stabilizers as shown in figure 1. This paper developed a realtime measurement system near the drilling bit and extracted the lateral vibration, longitudinal vibration time series of bottom rotating drill string. Approach to solving the problem of vibration during the. In this paper drill string of horizontal well is object being studied. One or more vibration damping modules are also spaced along the length of the drill string. It will also discuss troubleshooting of the problems that may occur. Drill string vibrations are an important cause of premature failure of drill string components and drilling inefficiency. The drill string natural frequencies and critical speeds vary during the drilling process as the well deepens and the drill string length. It enables engineers to determine forces and motions at every location along the drill string in userdefined engineering. A drill string on a drilling rig is a column, or string, of drill pipe that transmits drilling fluid via the mud pumps and torque via the kelly drive or top drive to the drill bit. In extreme cases of torsional oscillations, the drillbit can come to a standstill for a short period of time, resulting in stickslip as shown in.
Drill string vibration is an important factor to influence the normal operation of drilling string system, and lateral vibration is the most complex and most severe vibration form. Citeseerx torsional vibrations in drillstring systems. Institute of dynamics and vibrations drill string dynamics. Lateral vibrations which occur in the forms of whirling and parametric resonance have also been studied extensively 8. Vibration analysis of flexible multibody drill string. Department of energys geothermal technologies program is dedicated to the many government employees at headquarters and at offices in the field who worked diligently for the programs success. Pdf the governing equations of motion for a drill string considering coupling between axial, lateral and torsional vibrations are obtained.
Pdf drill string vibration modeling including coupling. The ipdt has demonstrated 50% improvements in rate of penetration rop and doubling of bit life in the field due to reduced vibration. Ground monitoring of bottom hole assembly vibration in. Smoothdrive the new concept of smoothdrive strapless design adds more benefits for blast hole drilling. This type of sticking is particularly unusual in that stuck pipe can occur while drilling.
Us9458679b2 apparatus and method for damping vibration. Publishers pdf, also known as version of record includes final page, issue and volume. The drillstring exhibits severe stickslip vibration induced by the contact between the drill bit and the formation. Modeling of wave propagation in drill strings using vibration. The manual control applied to the electrical jack is also noticeable by looking at the wob curve. Drillstring vibrations and vibration modeling product sheet.
This work describes the first experience in brazil on identification and suppression of vibrations of the pipe string during drilling operations. Reducing drillstring vibration and stick slip events to improve drilling e. Combined with features of flexible multibody drilling string system and topdrive drilling system, the characteristic equation for lateral, twisting and longitudinal coupled vibration of flexible multibody drilling string system is developed based on elastic vibration theory and finite element method, and the lateral vibration constraints is restored. Introduction deep wells for the exploration and production of oil and gas are drilled with a rockcutting tool driven from the surface by a slender structure of pipes, called the drillstring. You cannot avoid these drill string vibrations three modes of vibration axial torsional lateral vibration modes. Even if the pieces are bonded together, impacts from the bha due to drill string vibration can cause the formation to fall into the well bore. The string consists of several tubular beams where each represents a drill pipe, drill collar, stabilizer, crossover sub or a bit. George armistead, larry wolfson we have been presenting drill string design workshops for over 12 years.
Control of stickslip vibrations in drilling systems technische. For example, 19 includes 19 characters to the right of the start position in the output. Also excessive vibration can cause pipe failure, washouts and decrease in the penetration rate. Even lowlevel, stickslip vibration can be a major cause of bit wear and reduce the speed of penetration. Study on lateral vibration characteristics of a drill string. Pdf the governing equations of motion for a drill string considering coupling between axial, lateral and torsional vibrations are obtained using a. We have been presenting drill string design workshops for over 12 years for all types of operations around the world. In rotary drilling, vibrations of the drill string, whether lateral, torsional or axial, play an important role in the drilling of a well and. Drill string vibration is inevitable low levels are usually harmless severe vibrations are destructive vibrations can be controlled to a degree.
The amegavibe is an extended reach drilling vibration tool that imparts high energy, low impact excitation to the drill string and bha while substantially reducing friction, improving bit weight transfer, and eliminating weight stacking. The drilling depth can also be extended by the addition of jointed drill string sections. Chaotic vibration analysis of the bottom rotating drill string. Adamsdrill is a toolkit we developed to predict the dynamic behavior of a drill string, including any nonlinear and fully coupled axial, lateral and torsional responses to various sequences of surface control parameters. In order to further understand the lateral vibration characteristics of modes and dynamic for drill string, effectively prevent drill string failure, and improve the service life of drill string, a lateral vibration. Mitigation of drill string vibration with respect to hole enlargement tools is of major interest because this can lead to reduced drilling costs, longer tool life. Erratic surface torque and drillstring vibrations eliminated. Stickslip is often seen while drilling and is a severe form of drillstring torsional oscillation in which. Study on lateral vibration characteristics of a drill.
In order to further understand the lateral vibration characteristics of modes and dynamic for drill string, effectively prevent drill string failure, and improve the service life of drill string, a lateral. Drill string vibrations can diminish the life of the pipe by accelerating the process of fatigue. Jul, 2016 drill string vibration is an important factor to influence the normal operation of drilling string system, and lateral vibration is the most complex and most severe vibration form. Ground monitoring of bottom hole assembly vibration in drill. Us9458679b2 apparatus and method for damping vibration in a. A history of geothermal energy research and development in the united states drilling i drilling this history of the u. Modelling and analysis of bha and drill string vibrations the research project is aimed at developing an experimentally verified analytical model describing the vibrations of the bottom hole assembly bha and drill string employed in oil and gas extraction. By isolating axial bit vibrations from the drill string, the shock tool will reduce lateral and torsional drill string vibrations, and related fatigue damage or failure of the rotary connections. The impact of soft torque technology on drilling performance. Drill string and components this chapter of the iadc drilling manual is concerned with the specifications, operating data, and the care and handling of drill string. Theeffect ofrotation plays a crucial role in understanding the bending vibration of a rotating drill string.
Modeling of wave propagation in drill strings using. Then, the measured signals are reduced, encoded in mud pulses, and transmitted through the mud to the ground. The combination of the drillpipe, the bottomhole assembly and any other tools used to make the drill bit turn at the bottom of the wellbore. Drillvibe provides a continuous realtime solution to mitigate risks and improve drilling performance in any drilling environment. Reduce risk and avoid npt energy had experienced high vibrations levels and surface torque fluctuations while underreaming the. A two degreesoffreedom lumped parameters model is employed to account for axial and torsional vibrations based on the model proposed by christoforou and yigit j. Predicts lateral, axial and torsional critical drilling speeds, enabling reduced vibration damage while increasing rop displays the deflected mode shapes and natural frequencies predicts drill string response to excitation forces developed by the bit, mud motors and drill string rotation.
We consider and investigate the complex matter of drill string dynamics using various time and size scales, as well as problemspecific model complexity, and a flexible, modular model setup. The interaction between bha and drillstring contact points may, in certain circumstances, drive the system into backward whirl. Iust international journal of engineering science, vol. Drillstring vibration analysis using differential quadrature. We investigate experimentally and numerically suppression of drillstring torsional vibration while drilling by using a sliding mode control. Bottom hole assembly bha design, drill string design, torque and drag analysis, as well as.
The directional wells and other special trajectory drilling technologies are often used in deep water, deep well, hard rock, and brittle shale formations. The vibration at the bottom hole assembly bha of a drill string system dss is generally monitored by using vibration transducers installed in or close to the bha. Hydraulics and hole cleaning, vibration and wellbore stability, equivalent circulation density management, as well as mud rheology and solids control. In this paper, the some models about the axial vibration, the lateral vibration and the torsional vibration of drill string are set up in deep wells for the actual situation and these models are calculated with the ansys software. Torsional vibration is defined as the twisting movement of the drill stem components drill pipe, bha and bit during rotation. This string undergoes various types of vibrations during drilling. Numerical and field data analysis of drill stem vibration. It reduces stickslip, especially when drilling with a steerable pdm motor. Realtime vibration and stick slip monitoring to improve. The iadc definition of a drill string is drillpipe with tool joints attached. Differentialpressurepipesticking problems may not be entirely prevented.
Drillstring vibrations and vibration modeling product. The challenger downhole tools shock tool effectively reduces impact loading on the bit to extend bit life and reduce bit trips. In this work, we model and analyse drillstring vibrations. The vibration rule of drill string is obtained under different situation. Pdf drillstring torsional vibration suppression using ga. The drill string is supported by the top drive in the derrick, which rotates the drill string at the surface to drive the bit and allow the drill string to advance downhole. Jul 11, 2012 in this work, we model and analyse drillstring vibrations. The term is loosely applied to the assembled collection of the smuggler pool, drill collars, tools and drill bit. Suppression of drillstring stickslip vibration vahid vaziri1.
Analysis on drill string vibration in deep wells by ansys. Torsional vibration such as stickslip vibration is considered to be one of the most common causes for drillstring system failures. Objectives understanding drill string vibrations types of vibrations and consequences recognizing and dealing with vibrations. Other downhole drill string components, like mwd lwd tools, also benefit from lower vibration. The drill string rotates during drilling, with a typical borehole diameter. Mathematical modeling and analysis of drill string. Top panel shows a typical torsional vibration of the drillstring, where the drillbit angular velocity varies with high amplitude around the angular velocity of the top of the drill pipe. Drill string vibration mitigation during simultaneous. The study on harmonic vibration of drill string in. Torsional vibrations can cause irregular down hole rotation. Solution use integrated drilling solution incorporating prejob bha modeling, drillingtype underreamer, telescope highspeed telemetrywhiledrilling service, and modular vibration chassis to monitor shock and vibrations. This model was subsequently coupled to a lateral vibration model considering the. Sources of drill string vibration during hole enlargement can be the drill bit, hole enlargement tool, or bha.
The result leads to a set of nonlinear equations with time varying. If sticking does occur, standard field practices for freeing the stuck pipe include. The drill string is tapered to maximize strength and hanging length by using lighter 5 in. The governing equations of motion for a drill string considering coupling between axial, lateral and torsional vibrations are obtained using a lagrangian approach. The drill string is hollow so that drilling fluid can be pumped down through it and circulated back.
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