Working together for a safer world
2013 Top Drive Systems Dropped Objects Prevention Workshop The upstream drilling industry has made signicant positive steps in the past decade towards the prevention of Dropped Object incidents. The result being that compared to a decade ago, overall dropped object incidents have been signicantly reduced on virtually all types of drilling assets globally. Asset owners (rig owners), operators (oil companies) and equipment manufacturers have all taken part with various levels of vigorousness in reducing the overall amount of dropped objects occurring on drilling assets. Unfortunately, the picture is not perfect. Dropped Object incidents are still occurring at a rather alarming rate globally and within all types of drilling assets, making it painfully obvious that it is not an asset type or regional related phenomena. A review of Dropped Object incidents highlights that they originate from a variety of root causes in a variety of systems. Thus realistically, realistically, a simple solution cannot be easily found; instead multiple solutions with multiple approaches will be required to continue the drive towards Dropped Object free operations. Originally initiated and fully supported by Brunei Shell Petroleum Company, the Lloyd’s Register Global Technology Centre (Singapore) with cooperation from Lloyd’ Lloyd’ss Register Energy Drilling, facilitated a one day workshop titled “Preventing Top drive Systems related Dropped Objects”. Objects”. This took place on the 12th November 2013 at the Lloyd’s Register Energy Drilling Training facility. The Singapore Lloyd’ Lloyd’ss Register Global Technology Centre (GTC) is set up to advance technical innovation and support the industry. industry. In collaboration with business, academia, and public research and development agencies, the GTC will focus on ve main research themes critical to safety in the energy and marine sectors and welcomes research proposals from across the industry. industry. The GTC aims to build strong energy related R&D capabilities in Asia, develop partnerships with research institutes, regulators, and governments. It also aims to assist industry partners in introducing new technology to solve challenging issues, and act as a catalyst for industry thought, leadership, and training. Lloyd’s Register Energy Drilling is the result of the merger Lloyd’s between two companies, ModuSpec International and WEST Engineering. The merger which occurred in 2012 combines 50 years of experience on drilling assets, including Dropped Objects Prevention Schemes. Lloyd’s Register is currently in the nal stages of developing Lloyd’s a DROPS class notation. This notation will provide guidance
to rig owners and will set a minimum standard for Dropped Object prevention measures to be put in place for a mobile offshore unit (drilling rig) to become eligible for the DROPS class notation. Supported by Brunei Shell Petroleum Company, Lloyd’s Lloyd’s Register attracted the participation of important players in the industry. industry. Thus on the 12th of November multiple operators, multiple rig owners, and a major manufacturer were present. Through this workshop and anticipated subsequent DROPS workshops, Lloyd’s Lloyd’s Register along with industry partners hopes to collate additional improvements in order to achieve its Dropped Object incident free target. The main goal of the workshop was to take a step back and approach ‘Dropped Object incident prevention’ from a fresh perspective, allowing new ideas to develop and exploring new directions. The target was not to nd immediate solutions and draw nal conclusions but was dened as “facilitating a joint industry discussion with the objective of identifying and exploring opportunities to minimise the occurrence of Dropped Objects”. Objects”. Equipment system boundaries were dened based on recent incident data from Brunei Shell Petroleum Company; highlighting that an increased quantity of Dropped Object incidents are related to Top Drive Systems (TDS). Based on the historical data provided by Brunei Shell Petroleum Company and the historical data available at Lloyd’s Register Energy Drilling inspection records, the following high level areas were dened to be explored. 1. Equipment and Systems 2. People 3. Management Systems An additional subsection was created, to divide between: A. New TDS Systems (looking forward) B. TDS Systems in use (current) To provide structure structure for the discussions the analysis of historical data was divided up into 4 focus areas. These were; 1. Collisions (between top drive and structure or stand while TDS is moving) 2. Failed xing and securing securing (e.g. sheared or loose loose bolts) 3. Maintenance, inspection, and replacement 4. (Sub)vendor supplied parts
Upon completion of the one day workshop, Lloyd’s Register held a number of internal follow up workshops, detailing dened areas for further exploration by Lloyd’s Register or by Lloyd’s Register and the industry combined. This paper describes the areas Lloyd’s Register distilled from the one day industry workshop on Top Drive System Dropped Object prevention. Note that these areas of focus are listed in no particular order of priority.
A. New Design Top Drive Systems A major positive contributor which would prevent dropped Objects from Top Drive Systems is a signicant design change. The current design of virtually all manufacturers is typically based on a design originating decades ago. Although from an operational and engineering point of view it meets the intended purpose, signicant improvements can still be made with regard to integrated Dropped Object prevention. Fully enclosed TDS’s should be explored with suitably strong panelling, hinged appropriately, and at the same time allowing for full internal inspection. The only external parts being the drill stem shaft protruding from the bottom of the enclosure. TDS pipe handlers and link tilt mechanisms all to be fully enclosed so that any Dropped Object would be retained inside the enclosure. New Top Drive Systems should be fully set up to accept foreseeable other vendor items. Typical examples are the rotary hose connections. Due to lack of an “imbedded” strong point to accept secondary securing for rotary hoses, (ill-tting) custom made clamps are often used, introducing quantities of additional bolts, nuts and steel parts. A persistent notion in the drilling industry is that full automatic pipe handling and automatic drilling is a technology still decades away from implementation. Multiple operations in other industry sectors are highlighted which have been fully automated successfully, improving safety and improving overall operations speeds and efciency. Deep-water pipe laying efciency sharply increased when pipe handling of small and large diameter pipe sections became fully automated. Lloyd’s Register is convinced that a Dropped Object incident free operation will require further development and use of automation and automated zone management.
B. Top Drive Systems in use Existing conventional and new TDS’s are complex equipment, designed for high load applications and a variety of different tasks; tripping, drilling, handling BOP and marine riser etc. The variety of tasks and the high load factors require a range of sub systems to be installed on a typical TDS such as pipe handlers, hydraulic cylinders, oil lubrication pumps, all of which are usually bolted on the sides. The rst major improvement that can be realised is to identify items that can be removed and eliminated from the TDS. Manufacturers are to re-visit current and future designs and verify items to be removed from a TDS by either omitting or relocating them to the xed position in the derrick or on the drilloor. The mantra “less is more” seems to be in place; less appurtenances create a situation of enhanced protection against Dropped Object
potential. After all, the best protection against Dropped Objects is achieved by not having the object at height at all. Proper attention to the primary xings is the start to achieving a reduction in the potential for Dropped Objects. Once sufcient attention in the design is given to the selection of an optimal xing method, and the equipment is installed accordingly, the most important target should be to maintain the original bolting, clamps and other xings and keep these in good condition. Secondary retention and securing are only “secondary”. Lessons can be learnt from the airline industry; the reason parts do not regularly drop from planes is not due to better secondary retention or securing; parts do not regularly drop from planes because the condition levels of the primary retention are typically maintained on higher levels than in the drilling industry. Occasionally sheared bolts occur on TDS’s, directly resulting in a dropped object. This would indicate a design failure if bolts shear before reaching the replacement point of the said item. However there are strong indications that the industry nowadays is often operating TDS’s near the maximum operating envelope or even exceeding the envelope. Not necessarily in maximum load path, but more specically in the area of vibration and prolonged high torque near the end of the envelope. Industry consensus and maintenance manuals prescribe additional inspection after jarring, an operation typically associated with inducing high levels of vibration and torque. However all agreed that multiple other operations introduce similar levels of vibration and torque which currently are not followed by a similar inspection regime. Manufacturers concur that little data is available on the actual vibration levels experienced during operation of the TDS’s in the eld, being it relative or absolute. Once vibration levels are more accurately known by manufacturers by measuring them over an extended period and by exploring all types of operation, design changes can be implemented to achieve improved operational envelopes or optimal inspection schemes. Mounting accelerometers on multiple TDS’s for the duration of a drilling program was agreed to be explored further. The data is to be submitted to the manufacturers in order for them to analyse all aspects of their design against these vibration levels.
C. Zone Management and Anti Collision Historical data conclusively shows that multiple Dropped Object incidents originate from collisions of a TDS with the rig oor, equipment (drill pipe) on the rig oor, crown or with elevators clashing with the structure or monkey board trough extended link tilt system. Proven technology is available to prevent equipment collisions in any industry by utilizing a variety of approaches. Whether new or conventional units in service, to conclusively prevent equipment collisions two things need to happen in the industry: (i) Full acceptance of full automatic anti-collision prevention with kinetic measurement to incorporate speed and weight.
(ii) Incorporate different vendors into anti-collision management. As described earlier, the drilling industry seems reluctant to embrace new and automated technology. From discussions it has become apparent that a notion persists that automatic systems are slower than manual operations. This notion is virtually in all cases incorrect when operations are measured over a longer period of time. To prevent collisions, the operation cannot rely on manual handling alone. In addition to the drilling industry, other industry sectors have conclusively proven that when relying on human handling, equipment collisions will occur over time at a higher incident rate then in an automated environment. In manual mode, a driller consistently operates close to an “information overload” situation meaning the amount of information to be processed by a driller is simply larger than the individual is able to handle. This is a known phenomenon in many industries where subsequently automation has taken over certain actions to reduce the information load managed by the operator (driller) and allowing the operator to take a step back and monitor. Kinetic Energy Monitoring Systems are proven technologies which have been available already for over a decade. This should be the minimum standard on any existing drilling unit in order to target Dropped Object incident free operations by preventing rig oor and crown collisions and collisions between TDS and other equipment or structure. Equipment collisions often occur when different vendors are involved. Situations where one vendor has not taken enough consideration of equipment operating in the same area supplied by other vendors, or structures placed in the same operational areas, again supplied by a different vendor. For newly built drilling rigs, rig designers have to incorporate detailed zoning specications for drill oor equipment in order for equipment manufacturers to incorporate these specications into their operational design. For conventional drilling units already in use, proven aftermarket technology is readily available to prevent collision of the TDS with structures (monkey board) or equipment, including incorporating the extended elevator link tilt functionality.
D. Dropped Object Prevention Inspections
time frame is based on. It is assumed to originate from the time required to perform greasing activities on a conventional TDS. Lloyd’s register is not challenging whether 30 minutes is sufcient time to perform a thorough DROPS inspection on a TDS, but is challenging the industry to provide a sound basis for 30 minutes daily time available for both maintenance activities and DROPS inspection. • The industry to review how much time is required daily to both ensure operational uptime of the TDS (maintenance) and perform Dropped Object potential inspections. Once this correct amount of time (that can differ per rig / TDS) is identied, based on a sound review for these tasks, charter agreements between owner and operators should clearly specify the monetary responsibilities (“who will pay for the time required”). The argument “the operator does not allow us to do maintenance” is often not correct and not based on reality. The true argument is that the operator desires to minimise the cost of downtime it takes to inspect or maintain. The equipment owner has the ultimate responsibility to maintain their equipment according to the original equipment manufacturers specications or beyond, irrespective if the charter agreements support the nancial implication or not. This is the case in any industry. Thus whether the party will cover the monetary side of the duration is a simple contractual matter and unfortunately, is still not often clearly specied in contracts. • Charter agreements between owner and operator should clearly specify cost allocations for preventive inspection time on TDS, covering both maintenance and DROPS inspections. Maintenance crews typically undergo extensive training and gain experience in identifying failing components on any type of equipment by measurement and observation. The individuals on drilling assets globally who are involved in daily and weekly DROPS inspections on a TDS are often drill oor crews. Drill oor crews are typically not trained to identity failing components. They are trained and have gained experience in other areas related to drilling a well, handling drill pipe, recognizing well control situations. In order to achieve successful DROPS inspection with a zero Dropped Object incident rate, DROPS inspections on TDS must be carried out by suitable technically trained staff.
Whatever the level of automation or design, be it late generation or a conventional TDS, regular inspections with a • DROPS inspections on TDS to be carried out by suitable focus on identifying Dropped Object potentials are required on technically trained staff. and around a TDS. This is simply because no matter how well designed; a risk for a potential failure is always present. DROPS inspections in general are often described and Regular inspections should reduce the risk of these failures managed by HSE departments. It was highlighted that some becoming a potential Dropped Object hazard. equipment owners have included DROPS specic notes in their maintenance tasks. However, regular DROPS inspections are An often observed comment found by Lloyd’s Register and typically managed and driven by HSE departments. many DROPS audits and inspections globally, is “we do not get the time to do a proper DROPS inspection”. The workshop • Due to the technical complex nature of a TDS, regular highlighted an interesting fact; the 30 minute TDS daily DROPS inspections on a TDS are to be managed and driven regular inspection interval is widely known in the drilling by the maintenance department, and not by a non-technical industry amongst manufacturers, owners and operators. department, such as HSE or Drilling. However, it is not known or understood what the 30 minute
The multitude of sub systems and appurtenances installed on TDS is already mentioned and has resulted in the fact that any given TDS contains large quantities of fasteners in a wide variety of types. Manufacturers have been active in identifying and applying secondary retention means, however it was generally concluded that it requires a signicant skill level to identify all fasteners in such a manner that one can verify, within a limited timeframe, that the item is still in position and condition that it does not present a Dropped Object potential. Manufacturers have aided this by preparing “picture books”, highlighting in detail the various components and their secure position. The workshop highlighted the requirement for additional steps to facilitate DROPS inspections on a TDS by two means: • Prepare an application, suitable to be used on a (ruggedized and industry approved) hand held device that can be taken up on the TDS during inspections. The program is foreseen to display the content of the conventional picture book in a natural manner that will effortlessly steer an inspector by all areas on a TDS that are required to be inspected. The use of Human Engineering should contribute to identify the most optimal manner for an inspector performing the task. • Manufacturers are urged to develop visual identifying aids that clearly highlight items (fastenings) prone to become a Dropped Object potential. The simplest example is the use of contrasting colour paint to highlight inspection items as some rig owners have already initiated. Other examples are the use of signal (yellow) position indicators on each fastener, making it easy to identify a fastener which is not in secure position. This is to be incorporated in new design, but also to be developed and made available for aftermarket use. The access to the TDS was questioned in many cases. How realistic are the expectations of sound DROPS inspections, when the TDS can only be assessed by man riding methods. Even late generation drilling assets, typically outtted with man rider baskets (cherry pickers), still leave plenty of room for improvement. Looking forward, additional access areas should be designed into the structure (derrick) supporting a TDS with capability to fully access the TDS from all 4 sides and at all TDS heights. Similar set ups to BOP inspection platforms should be engineered, providing sound access platforms for multiple maintenance staff while working in a natural posture (standing upright on their feet).
• Future rig design to improve accessibility to TDS with full size platforms, readily available to be rigged up alongside TDS on all four sides and covering full TDS height, in order to allow for maintenance and inspection staff to perform tasks in natural human posture. Envisioned are platforms, hydraulically extended and retracted out of the derrick, to create walkway type platforms that are operational in a minimum time frame.
E. DROPS Standard The workshop conrmed what was earlier highlighted in many global inspections by Lloyd’s Register Energy Drilling, that there is a lack of recognised industry standards pertaining to DROPS. This lack of standards has resulted in regional differences in the approach of Dropped Object prevention and also differences between operators and owner’s vision on what sound practice is. Secondary retention methodologies are often not supported by sound engineering standards, but merely based on experience. This is sometimes driven by vendors supplying to the industry, presenting their items as “DROPS Proof” or with the notion “secondary retention built into the design”. The engineering methodology supporting the built in secondary retention is often not clear or impossible to retrieve. Risk assessments are often still not properly carried out when applying Dropped Object potential mitigation actions, such as when installing secondary securing. As a result, it is possible that more Dropped Object potential hazards are actually introduced, by not correctly incorporating this securing in the initial design, not correctly installing the secondary securing or applying unsuitable additional secondary securing measures. • An industry wide accepted standard is to be created for mitigation of Dropped Object potential.
Conclusion The approach to step back from the “bolts and nuts” and use the combined knowledge of the industry (owners, operators and manufacturers alike) has resulted in several new ideas and visions that are presented in this paper. Lloyd’s Register is committed to keep working together with the industry to further investigate and explore these new ideas in order to work towards the ultimate goal of DROPS incident free operations in the drilling industry.
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