Some scholars has carried on the experiment and analysis, and some of them presented vibration equation of the drill string 47. In drilling engineering, drill string premature damage are frequently observed, resulting in drilling cost and cycle prolonged. The drill pipe is acting as a torsional spring ks nmrad. The drill string is usually subjected to a complex combination of these loads. The governing equations of motion for a drill string considering coupling between axial, lateral and torsional vibrations are obtained using a lagrangian approach. Arithmetic solution for the axial vibration of drill.
Realtime vibration and stick slip monitoring to improve. In the open literature, the torsional vibration dynamics of a drill string has been. This need was largely sa tisfied, for the slow and robust machines of. On the basis of the study on drill string vibration rules in vertical well drilling and the idea of transformation of drill string vibration energy to drilling fluid hydraulic energy, a novel tool, downhole. Drill string shock and vibration in drilling youtube. Ground monitoring of bottom hole assembly vibration in. You will call yourself after doing this job,its a real job. Observerbased outputfeedback control to eliminate torsional drillstring vibrations t. The motivation for this dissertation is the need to understand the complex vibration states and the stability of the drill string in order to better control its constructive and destructive potential. Vibration models are a valuable tool as part of an engineered approach3,4,5,6 incorporating prejob analysis of offset well information, prejob modeling, realtime shock and vibration measurements, and postjob analysis and modeling6, but it is important to understand their limitations. 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. A proxy for identifying lithologic boundaries while drilling article pdf available may 2002 with 74 reads how we measure reads. Simulations demonstrated that vibration technologies can effectively reduce the axial friction of the drill string. The shock sub impact and vibration reduction tool is a drillstring component that absorbs and dampens the variable axial dynamic loads produced by the drill bit during routine drilling and milling operations.
Comparative analysis whether considering the lateral inertia or not, aiming at the longitudinal vibration of the drill string in drilling progress, is proposed. At other times, severe axial vibrations near the bit may show no visible vibrations at the surface. Lateral vibrations which occur in the forms of whirling and parametric resonance have also been studied extensively 8. Drillstring vibrations and vibration modeling product. Drillstring vibrations and vibration modeling product sheet. Reduce risk and avoid npt energy had experienced high vibrations levels and surface torque fluctuations while underreaming the. Large compliance of the lengthy oilwell drillstring in combination with low tool inertia and stickslip friction between the tool and rock bed causes the emphasized torsional vibrations of the. 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. 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. Longitudinal vibration equation of the drill string is derived from the rayleigh. 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. Iust international journal of engineering science, vol. Gap element method of longitudinal vibration of drill string.
In order to be able to identify and quantify different in. 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. 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. Longitudinal and torsional vibrations in a drill string consisting of drill pipe and collars, and the. Several domirlant mechanisms which cause the bending vibration of rotating drill strings have been identified, they a. The rig is capable of exhibiting of all major types of drill string vibrations, including torsional, axial and lateral modes. An analytical study of drill string vibrations onepetro. Vibration analysis of flexible multibody drill string system. Gradually, as vibration isolation and reduction tech niques have become an integral part of machine design, the need for accurate measurement and analysis of me chanical vibration has grown. It reduces stickslip, especially when drilling with a steerable pdm motor. Then, the measured signals are reduced, encoded in mud pulses, and transmitted through the mud to the ground. Citeseerx document details isaac councill, lee giles, pradeep teregowda. Investigation of drillstring vibration reduction tools.
Modeling of wave propagation in drill strings using vibration. Whirl interaction of a drill bit with the borehole bottom. Drillstring dynamics and vibration control oilwell. Induced axial vibrations at the bit can lead to lateral vibrations in the bha, and axial and torsional vibrations observed at the rig floor may actually be related to severe lateral vibrations downhole near the bit. Equipment, associated with directional drilling has become more and more complex and vulnerable to every mode of vibration. The vibration rule of drill string is obtained under different situation. The modal frequency equation of the sonic drill string with an inertial boundary is obtained via. Drill string vibrations can diminish the life of the pipe by accelerating the process of fatigue. 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.
The horizontal directional drilling process the tools and techniques used in the horizontal directional drilling hdd process are an outgrowth of the oil well drilling industry. The drilling assembly handbook is broken down into eleven 11 major sections, as described in the table of contents. In the open literature, the torsional vibration dynamics of a drill string. Pdf drill string vibration modeling including coupling effects. 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. Nijmeijer1 abstract torsional stickslip vibrations decrease the performance and reliability of. Many countries scholars have conducted indepth study on the issue of the drill string. Investigation of the influence of screw connections in drillstrings on the propagation of torsional waves with respect to advanced stickslip controllers omae2014 comparison of dynamic loading of light weight and steel drillpipes during tripping operations. Among the three vibrations, torsional vibration has attracted significant research effort partially due to its severe negative effects on drilling efficiency and life of drill string components.
Wiercigroch centre for applied dynamic research, university of aberdeen, scotland, uk m. In the light of the actual condition, the mechanical model of the drill string about vibration is established on the basis of the theoretical analysis. Results underreamed 24in pilot hole to 28 in with no shock and vibration or surface torque fluctuations. A governing equation for the flexural response that incorporates the effect of the drill string rotation is developed from first principles, and the resulting differential equation is found to have a variable coefficient, which is a function of the drill string rotational speed. Even lowlevel, stickslip vibration can be a major cause of bit wear and reduce the speed of penetration. The bit is considered to be an absolutely rigid ellipsoidal body with uneven surface. In order to avoid or minimize the impact of vibrations on operation conditions it is essential a deep dynamical investigation that allows a proper understanding of system dynamics. A proxy for identifying lithologic boundaries while drilling1 greg myers, 2 david goldberg, and james rector3 abstract during ocean drilling program odp leg 179, we recorded drill. Research article stickslip analysis of a drill string. The causes of these vibrations include impact and friction at the borehole drill string and bitformation interfaces, imbalances, eccentricity or initial curvature in the drill collar sections, various linear or nonlinear resonances. Drillstring vibration is a major contributor to downhole tool failure. An analytical study of drillstring vibration journal of. Effect of centrifugal force on natural frequency of lateral vibration. 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.
This paper presents investigations of a complex drill string vibrations on a novel experimental rig, developed by the centre for applied dynamics research at the university of aberdeen. Suppression of drillstring stickslip vibration vahid vaziri1. It is attached to the lower end of a rotating elastic drill string. Suppression of drillstring stickslip vibration by sliding.
With drilling, drill string vibrations typically include axial vibration, lateral vibration, and torsional vibration. The effect of the rotation of a drill string on the response of a drilling riser has been studied. The experiments are conducted on the novel experimental drill string dynamics rig developed at the university of aberdeen wiercigroch, m. Analysis on drill string vibration in deep wells by ansys. The study on harmonic vibration of drill string in horizontal. Moreover, the developed control law takes into account the vibrational frequencies and critical operating speeds of the drill string, thus also being capable of. The string consists of several tubular beams where each represents a drill pipe, drill collar, stabilizer, crossover sub or a bit. Drillstring vibrations and vibration modeling vibration types bit bounce drillstring vibrations can be divided into three types, or modes. Longitudinal and angular drillstring vibrations with damping. The exact form of the beam curvature is used to formulate the string. Drillvibe provides a continuous realtime solution to mitigate risks and improve drilling performance in any drilling environment.
The destructive nature of each type of vibration is different. Vibration indices comprising the integrated, lengthaveraged bending strain energy provide a good summary of the overall bha response that is particularly useful in bha design investigations, but it is the dynamics of the individual contact points that drive the dynamic response of the model. Oil drilling operations is usually associated with drill string severe vibration conditions that lead to an onerous and inefficient process. It enables engineers to determine forces and motions at every location along the drill string in userdefined engineering. In the perturbed state, the bit can roll without sliding on the borehole bottom, performing whirling vibrations the model of dynamic equilibrium with pure rolling when maximum cohesive force does not exceed the ultimate coulombic friction. During ocean drilling program odp leg 179, we recorded drill string vibration data to investigate the subseafloor environment as part of two seismicwhiledrilling experiments in may 1998. The stickslip phenomenon is one of the phenomena caused by these composite vibrations.
It may also cause hole damage and increase the need for more frequent rig repair. This paper deals with the theoretic simulation of a drill bit whirling under conditions of its contact interaction with the borehole bottom rock plane. In this study, the onedimensional wave theory is employed to establish the longitudinal vibration differential equations of the sonic drill string with vibrator mass. Citeseerx torsional vibrations in drillstring systems. The effect can be a gradual increase in drag over a number of metres, or can be sudden.
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. Drillstring vibrations and vibration modeling references. 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. This online work is like draw straightarrow and earn money. Drill string vibration is inevitable low levels are usually harmless severe vibrations are destructive vibrations can be controlled to a degree. Longitudinal and angular drillstring vibrations with. Effect of drill string rotation on the dynamic response of.
Modelling and analysis of bha and drillstring vibrations. The challenger downhole tools shock tool effectively reduces impact loading on the bit to extend bit life and reduce bit trips. P does not agree with t&d calculated bit torque below 14,500 this suggests that something other than bit torque was causing the drill string to experience such high torque on bottom torque. The iadc definition of a drill string is drillpipe with tool joints attached.
Drillstring vibration analysis using differential quadrature. 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. Absorb vibrations and impact loads caused by drill string movement steel rubber spring design to absorb torsional and vertical vibration placed normally above the bit stabilization requirement dictate placement 30 to 50 above the bit drill string design design means determination of length, weight, grades of drill. In rotary drilling, vibrations of the drill string, whether lateral, torsional or axial, play an important role in the drilling of a well and. Shock sub impact and vibration reduction tool schlumberger. 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 drill string. For the sake of simplicity, the effect of different types of friction, such as fluid, rubbing, and material, which act along the string, is approximated by the effect produced by viscous friction. A contribution to efficient calculation of complex drill. 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. Approach to solving the problem of vibration during the. Institute of dynamics and vibrations drill string dynamics. Analysis on drill string vibration signal of stick slip and. The rules of drill string vibration are obtained by the analysis on the vibration models.
Also excessive vibration can cause pipe failure, washouts and decrease in the penetration rate. Us9458679b2 apparatus and method for damping vibration in a. We investigate experimentally and numerically suppression of drillstring torsional vibration while drilling by using a sliding mode control. Timely detection and mitigation of downhole vibration is key to avoiding nonproductive time npt and preventing equipment damage. Modeling of wave propagation in drill strings using vibration transfer matrix methods. Drillstring vibration analysis considering an axial. The impact of soft torque technology on drilling performance. Drillvibe service was able to save 19 hours drilling the di. It will also discuss troubleshooting of the problems that may occur. The ipdt has demonstrated 50% improvements in rate of penetration rop and doubling of bit life in the field due to reduced vibration. The developed controller achieves the vibration mitigation by varying the upper rotary speed. 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. Computer programs based on the theory are used to calculate longitudinal and angular vibrations caused by periodic bit motions along the drill string.
The optimization systems new features include combining surface data with downhole vibration. Drillstring vibration analysis using nonsmooth dynamics. We investigate experimentally and numerically suppression of drill string torsional vibration while drilling by using a sliding mode control. Institute of dynamics and vibrations drill string dynamics group. The topics in the index will give the page numbers of information relating to specific drilling problems which you might face on the rig floor. Jul 11, 2012 in this work, we model and analyse drillstring vibrations. A proxy for identifying lithologic boundaries while drilling.
Axial vibrations can cause bit bounce, which may damage bit cutters and bearings. The term is loosely applied to the assembled collection of the smuggler pool, drill collars, tools and drill bit. In this study, the differential quadrature method dqm is applied to analyze the drillstring vibrations in a near vertical hole. The interaction between bha and drillstring contact points may, in certain circumstances, drive the system into backward whirl. In order to understand critical vibration of a drill bit such as stickslip and bitbounce and their wave propagation characteristics through a drill string system, it is critical to model the torsional, longitudinal, and. First, a nonlinear static analysis is performed to find the effective length of the string where it rests on the borehole wall. Researches show that, the common phenomenon of drill string vibration is the main cause of premature damage, thus more and more attention is paid to research on drill string vibration. Modeling and control of drillstring system with stick. It is most beneficial when drilling in hard rock, broken formations, and intermittent hard and soft streaks. Objectives understanding drill string vibrations types of vibrations and consequences recognizing and dealing with vibrations.
The harmonic vibrations rules of drill string of horizontal well are. Axial, lateral, and torsional vibrations are generally quite complex in nature. Vibrations in drillstrings have been a concern for many years. Proceedings of the ocean drilling program, scientific results volume 179 1. Modeling of wave propagation in drill strings using. Longitudinal vibration can reduce the axial friction such that the dependence of the reduced coef. Vibration drilling dynamics free download as powerpoint presentation. Equipment failures, especially those that occur in the bottomhole assembly, can be linked directly to severe vibrations. A novel tool to improve rate of penetrationdownhole. The result leads to a set of nonlinear equations with time varying. Our models range from complex to reduced models and down to minimal models with realtime.
Investigation of drillstring vibration reduction tools by mohammed fayez al dushaishi a thesis presented to the faculty of the graduate school of the missouri university of science and technology in partial fulfillment of the requirements for the degree master of science in petroleum engineering 2012 approved by dr. This work describes the first experience in brazil on identification and suppression of vibrations of the pipe string during drilling operations. Influence of sonic vibrator mass on the modal frequency of. Linear coupling between dnamic axial force and bending vibration parametrically excited bending vibration due to dynamic axial force whirling of the drill string with and without borehole contact. This approximation is generally accepted and appears to give adequate results for the drill string vibration problem. Among the three vibrations, torsional vibration has attracted signi cant research e ort partially due to its severe negative e ects on drilling e ciency and life of drill string components. Vibration technologies for friction reduction to overcome. This paper discusses longitudinal and angular drillstring vibrations and supporting field measurements taken with a special downhole recording instrument. In these studies, the torsional vibrations are not considered and the drill string is assumed to rotate at a constant speed. The components of a horizontal drilling rig used for pipeline construction are similar to those of an oil well drilling rig with the major exception being. Mathematical modeling and analysis of drill string. The vibration of drilling systems is particularly important. 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.
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