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Collaborating Authors
Abstract Running casing with conventional equipment is a labor intensive process requiring multiple personnel on the rig floor. Due to the dynamic environment of running casing with this equipment, there is elevated potential for accidents. Two specific operational hazards associated with hydraulic power tong operations (the "mule kick" and "rattlesnake") have been addressed, and the authors are developing solutions to mitigate future related incidents. A new system, utilizing a programmable logic controller (PLC) and position sensors, as well as hydromechanical and electromechanical devices, has been devised to reduce the chance for injury and enhance safety for casing power tong operators. Risk mitigation through engineered safety controls is a primary objective for service companies, and the operators and contractors they work with. Hydromechanical, electromechanical, and electronic control (PLC) devices for land-based, conventional casing equipment are under development and revision. These devices are being customized for incorporation into power tongs and hydraulic power units. In conventional operation of power tongs, the power unit modulates the amount of hydraulic power provided to the tong based on required flow rate and pressure. The PLC provides the ability for electronic communication between the power tong and power unit, virtually eliminating lag in response time. The logic control can also determine, based on the magnitude of tension in the backup line, if the tongs are actively in make-up or break-out mode. These devices under development will prevent the violent backlash and stored energy associated with the "mule kick" and "rattlesnake". In addition, due to the flexibility of the system, Human Machine Interface (HMI) screens can be provided to adapt the system to changing conditions. The application of the logic controller and mechanical devices on land-based, conventional casing running equipment is a significant step in reducing operator and equipment error, and increasing the casing crew's safety threshold. This paper will discuss the evolution of this system, from conception to application.
ABSTRACT ABSTRACT Sucker-rod pin breaks are the result of improper prestressing of the pin during makeup. This paper discusses the-recommendations of two API task groups as to how to measure the proper prestressing and how to consistently achieve it with power tongs INTRODUCTION Despite substantial efforts, sucker-rod pin breaks continue to plague the industry in wells where the rod strings are highly stressed. The principal cause has long been identified as improper prestressing of the pin. However, the past efforts of operators, manufacturers, and API task groups have not eliminated the problem Two API task groups have been working on this problem One, the Task Group on Sucker-rod makeup, has been concerned with determining the proper pin stress and the means of establishing it. The second, on Power Sucker-rod Tongs, has worked on a method of utilizing power tongs to consistently get the desired stress These two groups have made recommendation on practices which are to be included in API RP 11BR Recommended Practice for Care and Handlling of Sucker Rods The author has had the privilege of working on the Power-tong Task Group for the past 2, years and has had the occasion to sit in on some of the Makeup Task Group's meetings. As a result, he is in a position to report on the progress and recommendations of these two groups He is not in a position to take credit for the work that they have done, but is acting as a reporter only. NEED FOR STUDY BY TASK GROUPS The need for proper prestressing of the pin when it is made up is well-known and accepted by the industry A low prestress will result in the separation of the pin face from the coupling face, permitting the coupling to unscrew and allowing corrosive well fluids to be "pumped" in and out of the joint Of even more concern is that when the shoulder faces separate, the pin is subjected to the entire pumping load rather than the 42-54 percent it would normally carry when the faces remain in contact. This results in a higher-than-normal stress range on the pin. On the other hand, if the prestress is too high, the yield strength of the pin may be exceeded or the cyclic load may cause fatigue failure of the pin. Obviously, there must be an optimum prestress that will maintain the contact between the coupling faces. but will not make it susceptible to failure from cyclic loading. The desired prestress can be determined by calculations, but it is difficult to achieve it in field operations Past practices have advanced from the "strong-man" method, to the present practice of torque measurements and use of power tongs. The "strong-man" method has obvious limitations. There is no way of measuring the pin stress other than by the "feel" to the rod wrencher, who is always most tired when he make up the last rod and where the highest prestress is needed. Furthermore, work done by manufacturers has shown that a man cannot impart the proper stress in larger-size rods with conventional rod wrenches The use of the power tongs was a long step forward They could be calibrated to provide a given torque, Which in turn could be related to pin stress. This was a great advance. but was still subject to limitation The industry settled on torque as being the criterion for rod makeup, forgetting that this was only an indirect method of measuring pin stress.
ABSTRACT ABSTRACT The Offshore Company has recently installed and put into operation a hydraulic pipe-handling system on its newest drilling vessel, Discoverer II The design and development of the pipe-handling system was a joint effort by Byron Jackson, Inc and The Offshore Company The purposes of the system are to increase the ability of the rig to operate in bad weather, to increase safety, to reduce the size of crew required, and to increase the speed of operation The system provides completely remote handling of the drill string during tripping, requiring only three men to operate the equipment It can rack vertically in the derrick over 16,000 ft of 5-in drill pipe, plus 10 stands of collars. In addition, it provides power assistance to many other operations such as, but not limited to, running casing and handling the Kelly. DISCUSSION In May 1968, The Offshore Company completed the rig-up of its newest drilling vessel, Discoverer II, and spudded in on its first location in the Bass Straits off the southeast coast of Australia The high point in the long list of the vessel's specia1 equipment and the subject of this paper is the rig's hydraulic pipe-handling system The main reason that The Offshore Company decided to put a pipe-handling system on the Discoverer II was to increase the ability of the rig to operate in bad weather But there were other reasons also safety to operating personnel would be increased, a reduction of the required number of crew members was anticipated, and an increased speed of operation was seemingly possible In order to get the best engineering know-how available for this project, Byron Jackson, Inc was contacted and a joint-venture agreement was made with them The system was designed and developed jointly by the two companies and built by Byron Jackson The first step was a preliminary design to establish the general concept of the system and to set the design guidelines to which we would work A second factor, but necessarily an important one, was that of time The system had to be limited to that which could be developed in time for installation on the vessel when it was ready This, in itself, set the major theme of designing the system around oil-field equipment that was already on the market, or could be quickly developed. The preliminary design produced the following criteria We would use the same basic racker scheme designed by Byron Jackson for an automated land rig in the mid-1950's The system would aim primarily for a three-man operation for tripping and would provide as much assistance as possible for or other operations The tripping speed was to be equal to that of a land rig, or roughly a stand a minute The system was to rack pipe vertically in the derrick and handle the full string of over 16,000 ft of 5-in drill pipe plus 10 stands of 7-3/4-in collars, or an alternate string of 3-1/2-in drill pipe and 4-1/4-in collars In addition, it was to assist in handling casing sizes up to 13-3/8-in The system was to be such that any or all functions could be done manually, in a more or less conventional manner, should the system malfunction
- Well Drilling > Drilling Operations (1.00)
- Well Drilling > Drilling Equipment (1.00)
- Well Drilling > Drillstring Design > Drill pipe selection (0.74)
- Information Technology > Knowledge Management (0.40)
- Information Technology > Communications > Collaboration (0.40)
- Information Technology > Knowledge Management (0.40)
- Information Technology > Communications > Collaboration (0.40)