Modeling and control of drillstring system with stick. Longitudinal vibration can reduce the axial friction such that the dependence of the reduced coef. Research article stickslip analysis of a 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. Drill string shock and vibration in drilling youtube.
Pdf torsional vibration control of drill string systems. Combining equations 1 and 3, the dynamic model of the. Longitudinal vibration equation of the drill string is derived from the rayleighlove. Combining fe method with monte carlo method into the bar model, stickslip behavior in the axial direction was obtained. He has worked in the dynamics and telemetry group on drill string modeling issues and drillstring dynamics since joining inteq. Vibration datasets in this study are from drill string data of an ultradeep well in kuqa, which is located in west china. 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. Lateral vibrations which occur in the forms of whirling and parametric resonance have also been studied extensively 8. The impact of soft torque technology on drilling performance fares attar, qatar shell. Combining 39, 40 and 50, 51 we obtain the feedback loop. 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. A methodology was presented to enhance drilling performance by combining inverted rate.
The drill strings experience high vibrations and strong rocks in the path of drilling. From ground to downhole, these com ponents serve as an actuator, connect ors, a stabilizer and a rock. 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. A proxy for identifying lithologic boundaries while drilling. The model results were in good agreement with the experimental data, verifying the accuracy of the established model. The challenger downhole tools shock tool effectively reduces impact loading on the bit to extend bit life and reduce bit trips. 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. Longitudinal and angular drillstring vibrations with. 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. Gamechanger, from sanvean technologies, is the software platform designed for merging and displaying. 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. Iust international journal of engineering science, vol.
Drill string vibration modeling including coupling effects. Normally, in petroleum engineering, the term stickslip is used for the torsional vibration of a drill string in vertical. The drill string vibrations coupled together with well bore friction result in many phenomenon such as bit bounce, stick slip, forward and backward whirl. The outer diameter of the tool joint is larger than the body of the drill. Longitudinal vibration equation of the drill string is derived from the rayleigh love. The above combine to provide reduced drilling costs and time to complete the well. Effects of vibration inducingabsorbing tools on drill string. Then, the measured signals are reduced, encoded in mud pulses, and transmitted through the mud to the ground.
According to the wall street journal, the deal will result in the. Mathematical modeling and analysis of drill string longitudinal. As the drill string starts to rotate from standstill, it has to counteract the static friction by. Lateral vibrations are the most destructive type of vibrations affecting rotary drilling. Pdf research on the mechanism of inplane vibration on. Also, drilling fluid is injected inside the drill string at the surface, and returns through the annulus area to transport cuttings, lubricate and cool the bit, among other functions. 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. 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. Washout in drillstrings washout can also develop due to cracks develop within drill pipe due to severe drilling vibrations. Study on lateral vibration characteristics of a drill. Pdf drill string vibration modeling including coupling effects. In these studies, the torsional vibrations are not considered and the drill string is assumed to rotate at a constant speed. Numerical and field data analysis of drill stem vibration. 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.
In severe cases, drill stem vibration may lead to wellbore instability that. 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. At other times, severe axial vibrations near the bit may show no visible vibrations at the surface. The results indicated that the drill string transverse velocity is a prerequisite for reducing axial friction. Vibrations generated in a drill string while drilling generally lead to a. Vibration technologies for friction reduction to overcome. Drillstring vibrations and vibration modeling product.
The drill pipe has two tool joints, one female is called a box and the other male is called pin. The results are axial, lateral, and torsional vibrations of the drill string, which are believed to be a fundamental cause of drill string failures. This paper discusses longitudinal and angular drillstring vibrations and supporting field measurements taken with a special downhole recording instrument. Pdf drillstring torsional vibration suppression using ga. Of the three types of vibrations of drill strings, lateral vibration and. The time to download, merge edr data, and deliver to the client is extremely important due to the fast pace in which rigs drill and walk to the next well on a pad. Drillstring horizontal dynamics with uncertainty on the.
Modeling friction performance of drill string torsional. The influence of drill string torsional oscillation on the axial friction force is discussed. Geolog specialists use sophisticated software to monitor and interpret high frequency drilling data. They are recognized by a phenomenon popularly known as drill bit whirl. A contribution to efficient calculation of complex drill. 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. These cause the dynamics presented by drill strings to be highly complex, non linear and unexpected.
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. Ground monitoring of bottom hole assembly vibration in. The ipdt has demonstrated 50% improvements in rate of penetration rop and doubling of bit life in the field due to reduced vibration. In 2,3, axial vibration of the drill string is studied to improve the dynamic behaviour of the system during stickslip phenomenon and to. A methodology was presented to enhance drilling performance by combining inverted. Which in return the entire above four points combine to lead to unnecessary. Objectives understanding drill string vibrations types of vibrations and consequences recognizing and dealing with vibrations. 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. During drilling a drill string can vibrate in any or all of three basic modes. The vibration of drill strings is a very complex subject, especially because of the nonlinear bitrock and drill string borehole interactions.
In the open literature, the torsional vibration dynamics of a drill string has been. Axial and torsional selfexcited vibrations of a distributed drillstring. While drilling, drillstring vibration causes premature drillstring components and bit failure 8, and. Drill string horizontal dynamics with uncertainty on the frictional force. An analytical study of drillstring vibration journal of. Drillstring vibrations and vibration modeling product sheet. The drillstring means the tubulars and the accessories used to run the drill bit to the bottom. Pdf failure of drillstrings is very costly in terms of money and time and occurs more. Drillstring vibration is a major contributor to downhole tool failure. In addition to displacement we can also describe the. The interaction between bha and drillstring contact points may, in certain circumstances.
Approach to solving the problem of vibration during the. 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. Proceedings of the ocean drilling program, scientific results volume 179 1. 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.
The impact of soft torque technology on drilling performance. In addition, low amplitude of torsional vibration speed can significantly reduce axial friction. 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. Stickslip is often seen while drilling and is a severe form of drillstring torsional oscillation in which. Torsional vibrations can cause irregular down hole rotation. 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 constitutes the majority of the drill string length. Dynamic model of an oilwell drillstring with stickslip. Lateral vibrations which occur in the forms of whirling and. The major causes leading to drill bit whirl are identified as the effect of a bend drill string or a manufacturing unbalance in the drill bit. It may also cause hole damage and increase the need for more frequent rig repair. 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.
For the solutions of drill string vibration analysis methods with complex influence factors and. Timely detection and mitigation of downhole vibration is key to avoiding nonproductive. Other downhole drill string components, like mwd lwd tools, also benefit from lower vibration. The rig is capable of exhibiting of all major types of drill string vibrations. Analyses of the robustness of the mathematical model with. Realtime vibration and stick slip monitoring to improve. Axial and torsional submodels use a lumpedsegment approach, with each submodel having a total of 21 segments to capture vibration of the kelly, drill pipes, and drill collars. The second is a realtime system to monitor 3axis drillstring vibration, and related parameters.
The established model, an improved dynamic friction model established for drill strings in a wellbore, was used to determine the relationship of friction force changes and the drill string torsional vibration. The pilot sensor is used to record the axial vibrations that travel up. Drillstring vibration analysis in extended reach drilling utpedia. The drilling assembly handbook is broken down into eleven 11 major sections, as described in the table of contents.
A proxy for identifying lithologic boundaries while drilling article pdf available may 2002 with 74 reads how we measure reads. Pdf a modified model for predicting the friction force between drill string and borehole wall under inplane vibrations was developed. Static bending stresses in catenaries and drill strings j. Underream 24in directionally drilled pilot hole to 28 in without bhadamaging drillstring vibration or erratic surface torque solution. Several domirlant mechanisms which cause the bending vibration of rotating drill strings have been identified, they a. Disclosed is an apparatus for vibrating a downhole drill string operable to have a drilling fluid pumped therethrough. Index terms deflections, drill, principal, stresses, strings i. Experimental evaluations of drill bit and drill string. In the open literature, the torsional vibration dynamics of a drill string has been modeled in several ways 24. Placed between the bit and drill collars 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.