As fixed cutter bits also known as pdc bits are especially prone to. Pdf this paper involves the dynamic stability analysis of distributed. The apparatus comprises a tubular body securable to the drill string and having a central bore therethrough, a valve in the tubular body for venting the drilling fluid out of the drill string and a valve actuator for cyclically opening and closing the valve. Analytical correlations of the equations of motion. A new drilling methodearthwormlike vibration drilling. Experimental evaluations of drill bit and drill string. A proxy for identifying lithologic boundaries while drilling article pdf available may 2002 with 74 reads how we measure reads. While drilling, drillstring vibration causes premature drillstring components and bit failure 8, and. Severe torsional drillstring vibrations can affect drill pipe and also bit life.
A contribution to efficient calculation of complex drill. We combine the objective function and the constraint condition as follows. In order to be able to identify and quantify different in. The drill pipe constitutes the majority of the drill string length. Proceedings of the ocean drilling program, scientific results volume 179 1. Lateral vibrations which occur in the forms of whirling and. Which in return the entire above four points combine to lead to unnecessary increased. Drill string axial vibration and sonic head analysis. Drillstring horizontal dynamics with uncertainty on the.
The vibration parameters, acceleration, velocity and displacement. Working principle of the downhole drill string shockabsorption and hydraulic supercharging device. In addition, low amplitude of torsional vibration speed can significantly reduce axial friction. The results indicated that the drill string transverse velocity is a prerequisite for reducing axial friction. Drill string vibration analysis using nonsmooth dynamics approach. Vibration datasets in this study are from drill string data of an ultradeep well in kuqa, which is located in west china. Modeling friction performance of drill string torsional. It enables engineers to determine forces and motions at every location along the drill string in userdefined engineering. As the drill string starts to rotate from standstill, it has to counteract the static friction by. The drill string vibrations coupled together with well bore friction result in many phenomenon such as bit bounce, stick slip, forward and backward whirl.
Approach to solving the problem of vibration during the. Several domirlant mechanisms which cause the bending vibration of rotating drill strings have been identified, they a. The problem of drill string vibration occurs in drilling operations and it will affect the usage life of drill pipe and drill bits. The interaction between bha and drillstring contact points may, in certain circumstances. Pdf drillstring vibration analysis using nonsmooth. The rig is capable of exhibiting of all major types of drill string vibrations. Index terms deflections, drill, principal, stresses, strings i. 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 significant research effort partially due to its severe negative effects on drilling efficiency and life of drill string components. The objective is to develop a delaydependent control scheme such that the downhole vibrations can be minimized by.
Iust international journal of engineering science, vol. Ground monitoring of bottom hole assembly vibration in. A drill string on a drilling rig is a column, or string, of drill pipe that transmits drilling fluid via the. The frequency of rotation, and hence vibration of the pipe string, is tuned to the resonant. The term is loosely applied to the assembled collection of the smuggler pool, drill collars, tools and drill bit. Pdf the governing equations of motion for a drill string considering coupling between axial, lateral and torsional. Drillstring vibration analysis in extended reach drilling erd. The drill string is hollow so that drilling fluid can be pumped down through it and circulated back. 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. Drill stem vibration is a common reason for premature failure. Indeed, while whether dufeyte and henneuse 1991 felt that the most severe form of torsional vibration, stickslip, occurred. This paper is concerned with torsional vibration control of drill string systems.
These cause the dynamics presented by drill strings to be highly complex, non linear and unexpected. The mechanisms of friction reduction by vibrating the drillstring primarily include a. Then, the measured signals are reduced, encoded in mud pulses, and transmitted through the mud to the ground. In this paper, experiment apparatus for simulating drillstring vibration was established. Through a combination of damage to equipment, and increased downtime, drill string vibrations have been reported to account for 210% of well costs. Running the casing in the wellbore is an important issue when drilling an oil and gas well. In addition to displacement we can also describe the. Layout for drilling seismic wells by vibration method. The impact of soft torque technology on drilling performance. 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.
Ind may, 1963 guidelines for controlling drill string vibrations. When you are drilling in hard formations, liquefaction cannot take place. A fully coupled model for axial, lateral, and torsional vibrations of drill strings is presented. Collar rope broke pulled 6 12 stand of drill collars off the back of derrick half rap duration. The merit of this design is to combine drilling string shock attenuation and. 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. Publishers pdf, also known as version of record includes final page, issue and volume numbers. Drillstring vibrations can be divided into three types, or modes. Objectives understanding drill string vibrations types of vibrations and consequences recognizing and dealing with vibrations. In alluvial material, vertical vibrations are generally enough to drive down a drill string for many meters without the injection of any water or air. Study on lateral vibration characteristics of a drill.
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. 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. A new drilling methodearthwormlike vibration drilling ncbi. Control of stickslip vibrations in drilling systems eindhoven. Pdf excessive drill stem ds vibration while rotary drilling of oil and gas wells. Measuring units when we looked at the vibrating tuning fork we consid ered the amplitude of the wave as the physical displace ment of the fork ends to either side of the rest position. Active suppression of drilling system vibrations for deep drilling. The outer diameter of the tool joint is larger than the body of the drill. Oscillations of the drill string are described by a wave equation in partial derivatives.
Development and application of the downhole drilling string shock. The principle of semiactive vibration damping developed by the authors using the matlab simulink graphical programming environment for modeling is studied. Longitudinal vibration can reduce the axial friction such that the dependence of the reduced coef. In 2,3, axial vibration of the drill string is studied to improve the dynamic behaviour of the system during stickslip phenomenon and to.
Selfexcited vibrations cause early fatigue of drill pipes and premature failure of bits and, therefore, should be avoided. Pdf torsional vibration control of drillstring systems. Analyses of the robustness of the mathematical model with. Vibration technologies for friction reduction to overcome. Timely detection and mitigation of downhole vibration is key to avoiding nonproductive. The basic principles and methods of drill string vibration control are studied. Pdf drill string vibration modeling including coupling effects. The energy from drilling string vibration is of high frequency and increases as well depth and formation anisotropy increase. Geolog specialists use sophisticated software to monitor and interpret high frequency drilling data. Three types of vibration, which are axial, lateral and torsional vibrations exist in the drill string. The influence of drill string torsional oscillation on the axial friction force is discussed. Simulations demonstrated that vibration technologies can effectively reduce the axial friction of the drill string.
Which in return the entire above four points combine to lead to unnecessary. 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. Pdf an analysis of common drill stem vibration models. The above combine to provide reduced drilling costs and time to complete the well. Longitudinal and angular drillstring vibrations with. The impact of soft torque technology on drilling performance fares attar, qatar shell. 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. The prospects of development of a semiactive vibration damping method are shown. Drill string vibration data sampling during the sample selection process, we need to consider the sample numbers, sample frequency, and sample lithology.
The drill pipe has two tool joints, one female is called a box and the other male is called pin. Drill string vibration is inevitable low levels are usually harmless severe vibrations are destructive vibrations can be controlled to a degree. Normally, in petroleum engineering, the term stickslip is used for the torsional vibration of a drill string in vertical. Realtime vibration and stickslip monitoring to improve drilling performance geologs drillvibe provides continuous realtime analysis of torsional vibrations at bit and along the drill string without the need for downhole lwd. Adaptive control of drill string vibrations springerlink. Analysis on the lateral vibration of drill string by mass effect of. Drill string horizontal dynamics with uncertainty on the frictional force. Pdf failure of drillstrings is very costly in terms of money and time and occurs more frequently than oil companies would like to see. Drillstring vibration is a major contributor to downhole tool failure. The drill strings experience high vibrations and strong rocks in the path of drilling. In such cases you can combine vibration with rotation, and use rock drill bits to cut the material. In this paper, the load transfer characteristics, advantages and feasibility of earthwormlike drilling are researched. In the open literature, the torsional vibration dynamics of a drill string has been modeled in several ways 24. We can combine the model of conventional drill string mechanics with the discrete lugre model to.
Interested in learning more about drill string components. The destructive nature of each type of vibration is different. Drill string vibrations, hole cleaning and well hydraulics. Ni are parameters to be evaluated, by combine all parameters together.
Drillstring vibrations and vibration modeling product sheet. Modeling friction performance of drill string torsional oscillation. 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. 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. Vibrations generated by the bit combine with those due to other sources, such as mass imbalance and wellbore friction, during drilling and reaming operations. First, a model is established to analyze the forces and motion of a drill string with one or several shakers, and a finite difference method with secondorder accuracy is adopted to solve this numerical model. Effect of tool joints on passages of plane longitudinal and torsional waves along a drill pipe j. Introduction uring oil and natural gas, borehole drilling operations, there are many engineering problems to contend with, as discussed in 1, including the failure of the drill string ds owing to the combined compression, buckling and torsional stresses encountered. In order to being able to guide a drillstring in any direction, came the significant task of modelling the whole process mathematically and physically. The outer diameter of the tool joint is larger than the body of the drill pipe to accommodate the threads. The second is a realtime system to monitor 3axis drillstring vibration, and related parameters.
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