Mechanized Rig Technology Increases Safety, Efficiency

Published Aug 22, 2005
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The industry trend toward mechanized drilling systems began almost two decades ago, and is still going strong. Tremendous advancements have been made and new technologies are continuously being developed. The goal? An increase in safety for rig floor personnel and improvements in overall operational efficiency.

This trend toward increased mechanization has driven both the implementation of new technology and the adaptation of existing equipment, helping the industry achieve safety and productivity goals that historically have not been possible.

Part of this trend is due to changes in governmental safety regulations. In the early to mid 1990s, for example, Norwegian authorities challenged service companies, drilling contractors, and suppliers of drilling equipment to remotely control all pipe handling processes on the rig floor and between pipe deck and well centre. The purpose was to improve safety by moving personnel out of harm’s way, and the transformation from manual operations to fully remote-control operation was underway. Many of the second- and third-generation rigs operating in the Norwegian sector at the time had early versions of pipe racking systems and iron roughnecks installed, but most rigs needed substantial upgrades with new pipe handling and makeup technology to comply with the remote-operation requirement.

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All-in-one PowerFrameT System

Significant technology advancements were quickly made, which soon enabled hands off pipe handling operations previously not possible. Since the mid to late 1990s, many new drilling vessels have adopted this technology. Rig mechanization and remotely controlled pipe handling systems and makeup tools, in particular, were part of the enabling technology that has led to the development of today’s fourth- and fifth-generation deepwater drilling vessels, many of which have dual-activity or simultaneous pipe-running operations. Many drilling rigs are in operation around the globe, however, which still require the use of older technologies, leading to safety concerns and often less efficient operations.

As legislation, safety concerns and higher efficiency standards continue to demand a shift towards fully hands-off operations, advances in mechanized technologies remain a high-focus area for the industry. Many innovative technologies have been introduced as a result of new challenges faced by operators in specific locations. These technologies can often be applied to wells around the world.

Multifunctional Iron Roughneck on the ULA Platform
In 2002, BP was planning drilling of an extended-reach well on the ULA platform offshore Norway in 2003. At that time, the rig had not drilled for more than a year, and new and more stringent safety regulations had come into effect. It was concluded that the iron roughneck on ULA would have to be upgraded or replaced, and furthermore several additional manual functions would have to be performed mechanically by remote control to comply with the new regulations and company safety requirements.

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Manual stabbing operations

At the time the ULA team was looking for alternative iron roughnecks, Weatherford introduced its new multifunctional PowerFrame™ iron roughneck system. Important to the ULA team was the fact that the drillpipe tool could make up and break out the majority of drillstring components including bottomhole assemblies (BHAs), stabilizers, and drill collars, without the use of manual rig tongs. This capability complied with the requirement for hands-off operations and improved the rig floor environment beyond what other iron roughnecks normally could do at the time. The extra torque capacity and the extended rotational wrenching capability of this tool could be valuable for making up demanding drillstring connections to be used for the upcoming extended-reach well. Of further value were the abilities to exchange the drillpipe tong module inside the system carrier with casing and tubing tong modules and to operate these tong modules from the same control panel as the iron roughneck.

Before the system could be quoted and evaluated against other solutions, however, the ULA team challenged Weatherford to develop a system that would also integrate their additional required features: a remotely operated mud bucket, a cleaning and doping device, and a stabbing guide. As a result, the development of the first integrated system with the ability to make up drillstring, BHAs, casing, and tubing began.

Development of the First All-in-One System
Weatherford designed the rail-mounted, modular PowerFrame system to accommodate a variety of mechanized power tongs for tubular makeup operations on the rig floor. This system, although it enabled quick change-out of tongs, was initially seen as another “casing roughneck,” capable of handling casing and tubing tongs.

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StabMasterT alignment tool

This perception changed, however, in 2001 when the firm introduced a new machine for drillstring make-up and breakout operations. The TorkWinder™ tool was developed to efficiently address the modern requirements presented by new drill pipe connections, such as HT, XT and WT. The result is safe, faster, more efficient operation with less connection damage. By design, the rotational wrench and spinner combination also addressed the makeup and breakout of drillstring connections in BHAs, stabilizers, subs and drill bits without the use of rig tongs. While these technologies had already proven to address new standards in both safety and efficiency, BP’s specific needs required additional advancements. Inspired by the opportunity and challenge, Weatherford developed and presented concepts for integrating BP’s requirements of a remotely operated mud bucket, a cleaning and doping device, and a stabbing guide. These concepts quickly developed into the All-in-One PowerFrame™ system – the first of its kind that would make up drillstring, BHAs, casing, and tubing. BP agreed to an initial one-well field trial period to test the new system on ULA.

Results: New System, Little Downtime
The added features of the new system worked flawlessly from the start and exceeded the operator’s expectations. During the fourmonth drilling operation, the Allin- One PowerFrame made up and broke out a total of 197,800 m (649,000 ft) of tubulars, with 7,774 connections. A total downtime of 4.5 hours was registered, while a total of 13.5 hours were logged for actual maintenance and repairs. BP has since purchased major components of the PowerFrame™ system while continuing to rent mechanized casing and tubing tongs and services.

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StabberlessT System in the derrick

Minimizing Injuries by Eliminating a Stabber in the Derrick
Another area in which rig mechanization can improve safety and efficiency on non-mechanized rigs is the stabbing operation, which continues to plague the industry with injuries.

In the 1990s, several attempts were made to develop tools to remove human error from difficult makeup process with special pipe, but not necessarily with the intent to improve personnel safety or efficiency. Then came the introduction of the programmable logic controller (PLC) and electronic position feedback systems that enabled various mechanized rig systems, including alignment tools, to be controlled remotely. The combination of PLC technology with the StabMaster™ alignment tool eliminated the need for mechanical adjustments in the derrick to achieve repeatable “fixed” joint alignment for tubular connections. Once the operator on the rig floor has adjusted the alignment correctly from the PLC remote-control panel, the alignment position is simply stored in memory by the press of a button. Automated repeated return to the same alignment position for subsequent joints ensures fast, accurate alignment with less need for operator input and without manual adjustments in the derrick. Whenever changing pipe sizes or otherwise readjusting the alignment, the operator simply stores the new alignment position from the PLC remote-control panel.

While this was a major advancement, these alignment tools still could not entirely replace the stabber in the derrick. Recognizing this concern, Weatherford created the Stabberless™ system, which is capable of running casing and other tubulars without a stabber in the derrick. The added features included remote control and interlocking of slip-type elevators and spiders, flagging devices indicating correct elevator position before closing the elevator around the upper joint (no stabber or camera required in derrick to guide the driller), and dual hinged singlejoint elevators that would not have to be opened up in the derrick.

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PowerFrameT II with 21-300 Riser tong on the rig

The first casing and tubing operations with this system were performed on land rigs in Holland in 1996, but it was not until 1998 that the industry truly started to realize the safety benefits and effi- ciency improvements of the system. Today, hundreds of casing strings are run without stabbers and without accidents, with an average timesaving of around 14% over previous manual stabbing operations on the same rigs. The timesaving is realized through simpler operation with a more precise repeatable alignment, resulting in fewer cross-threaded connections, less thread damage, and fewer rerun or rejected joints.

Initially, many drilling crews and casing running personnel expressed scepticism about the suitability of mechanized alignment tools on semi-submersibles and drillships; it was believed that dynamic rig motions would shift joint alignment. Repeated experience in areas like the North Sea offshore U.K, however, prove that not only does the system greatly improve safety and efficiency under normal weather conditions, it also enables continued operations during extreme wave and wind conditions when neighbouring rigs with manual stabbing operations have to shut down and wait for better weather.

The First 300,000 ft-lb Fully Rotational Tong
A major operator in the Gulf of Mexico was challenged with a deepwater SPAR in the Gulf of Mexico that required a small-footprint, yet lightweight tong that was capable of providing 300,000 ft-lb of continuous rotational torque to run outer production riser. The operator preferred mechanized equipment, and the rig was already equipped with Weatherford’s PowerFrame™ II tong positioning device. While the company’s existing 21-300 power tong would meet both the hightorque and small footprint requirements, it was developed long after the introduction of the PowerFrame II, and although light weight for its tremendous torque capability, the riser tong exceeded the maximum lifting capacity of the PowerFrame II.

To overcome this challenge, the Weatherford developed the ServoFrame™, an auxiliary to the PowerFrame II tong positioning device which was already on the rig. This combination of mechanized technologies successfully addressed both safety and efficiency concerns. Remote operation reduced the number of personnel on the rig floor during operation, and the use of mechanized equipment provided efficiency gains and ultimately significant cost savings for the operator.

Mechanized drilling technologies are frequently met with scepticism when first introduced. As time and experience have proven, however, advances in rig mechanization have led the way when it comes to improving safety and efficiency, and will likely continue to do so for a long time to come.

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