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This paper was prepared for presentation at the 1999 SPE/IADC Drilling Conference held in Amsterdam, Holland, 9-11 March 1999.
Abstract Inducing vibrations while drilling is a relatively new concept that shows promise in directional applications. Instigating motion of the drill string, particularly in the sections lying on the low-side of the wellbore, can lead to substantial improvements in managing the two limiting factors of the long horizontal wells that are typically associated with today's unconventional shale plays: removal of formation cuttings from the borehole, and frictional drag between non-rotating drill strings and the wellbore wall. Minimizing these effects, by introducing controlled vibrations, increases the overall drilling efficiency and reduces the cost associated with the well. The difficulty in implementing such actions, however, is consistency. Because the behavior of drilling assemblies is inherently nonlinear, it has been difficult in the past to reliably predict their response to dynamic events. This, in turn, creates a challenge when trying to optimize the performance of arbitrary Vibration Inducing Devices (VIDs). This paper presents a detailed analysis of the fully coupled, three-dimensional, nonlinear behavior of drill strings under the action of induced vibrations. Specific focus is given to the dynamic characteristics of a drill string, during horizontal drilling operations, in long unconventional wells and how this behavior affects the success of the well. The response of the drill string, due to induced axial and lateral oscillatory motions, is examined through linearized dynamic analysis and nonlinear timedomain simulations. Solutions obtained from the study provide a clearer understanding of the dynamics experienced down-hole and lead to suggestions for improved practices when drilling with lateral VIDs, particularly with regards to hole-cleaning. Further insights into the sliding and rotational behavior of the drill string, while using these types of tools, are drawn from animated modeling results. Finally, the future applications of this technology are discussed.
Abstract Handling tools have been improved and adapted, wherever possible, to aid remote automation on today's drilling rigs. Work that was done manually using elevators, spinning chains, tongs and brute force is now managed by using remotely controlled machines. The application of automation to improve the performance of drilling rigs has captured the attention of the drilling industry for years. Numerous rig designs have been tried with relatively few success stories. The history of drilling automation can be paralleled to the development of Pipe Handling Systems on the drilling rig floor. This paper offers examples to support the theory that there are four critical developments required to achieve automation on the drill floor. P. 695
Abstract On a Deep Gas Project in the Middle East, it is required to drill 3500 ft of 8-3/8" deviated section and land the well across highly interbedded and abrasive sandstone formations with compressive strength of 15 - 35 kpsi. While drilling this section, the drill string was constantly stalling and as such could not optimize drilling parameters. Due to the resulting low ROP, it was necessary to optimize the Drill string in order to enhance performance. Performed dynamic BHA modelling which showed current drill string was not optimized for drilling long curved sections. Simulation showed high buckling levels across the 4" drill pipe and not all the weight applied on surface was transmitted to the bit. The drilling torque, flowrate and standpipe pressures were limited by the 4" drill pipe. This impacted the ROP and overall drilling performance. Proposed to replace the 4" drill pipe with 5-1/2" drill pipe. Ran the simulations and the model predicted improved drill string stability, better transmission of weights to the bit and increased ROP. One well was assigned for the implementation. Ran the optimized BHA solution, able to apply the maximum surface weight on bit recommended by the bit manufacturer, while drilling did not observe string stalling or erratic torque. There was also low levels of shocks and vibrations and stick-slip. Doubled the on-bottom ROP while drilling this section with the same bit. Unlike wells drilled with the previous BHA, on this run, observed high BHA stability while drilling, hole was in great shape while POOH to the shoe after drilling the section, there were no tight spots recorded while tripping and this resulted in the elimination of the planned wiper trip. Decision taken to perform open hole logging operation on cable and subsequently run 7-in liner without performing a reaming trip. This BHA has been adopted on the Project and subsequent wells drilled with this single string showed similar performance. This solution has led to average savings of approximately 120 hours per well drilled subsequently on this field. This consist of 80 hours due to improved ROP, 10 hrs due to the elimination of wiper trip and a further 30 hrs from optimized logging operation on cable. In addition, wells are now delivered earlier due to this innovative solution. This paper will show how simple changes in drill string design can lead to huge savings in this current climate where there is a constant push for reduction in well times, well costs and improved well delivery. It will explain the step-by-step process that was followed prior to implementing this innovative solution.
Brown, Christian F. (ALTISS Technologies LLC) | Podnos, Evgeny G. (ALTISS Technologies LLC) | Saasen, Arild (University of Stavanger) | Dziekonski, Mitchell (ALTISS Technologies AS) | Furati, Mostafa Al (ALTISS Technologies AS)
Abstract Drill string vibrations are a significant concern during drilling operations, and are a common cause of downhole tool failures and decreases in drilling efficiency. Drill string vibrations are typically categorized in three ways: axial (the drill string is vibrating along the axis of drilling), lateral (the drill string is vibrating perpendicular to the axis of drilling), and torsional (the rotational speed of the drill string is varying along the axis of rotation). If applied correctly, the use of low elastic modulus and low density materials in a complex system will dampen vibrations. This hypothesis is confirmed through the use of multiple software simulations including an ABAQUS Finite Element Analysis (FEA) model and an MSC Adams multi-body dynamics model. The simulations pointed to the conclusion that including sections of aluminum drill pipe into the drill string will dampen drill string vibrations (Dziekonski, 2017). The low elastic modulus and density of aluminum reduce both the duration and severity of torsional vibrations in a stick slip type dysfunction. The reduction in severity of uncontrolled torsional oscillations will reduce the additional strain on threaded connections throughout the bottom hole assembly and drill string, as well as the impact caused by lateral vibrations, and the amplitude of axial vibrations. This overall reduction in vibrations can be used to increase the life of sensitive downhole components and increase the efficiency of drilling operations.