Offshore Technology Reports – Next Generation Drive & Control Solutions for Oil & Gas Operations by The Magazine Production Company

SPECIAL REPORT

Next Generation Drive and Control Solutions for Oil and Gas Operations

Next-Generation Heave Compensation for Maritime and Offshore Applications Under Pressure: How Tight Profit Margins Govern the Introduction of New Technology Facing the Challenge: New Technology for a New Age

Sponsored by

What the Future Holds

Published by Global Business Media

Published by Global Business Media Global Business Media Limited 62 The Street Ashtead Surrey KT21 1AT United Kingdom Switchboard: +44 (0)1737 850 939 Fax: +44 (0)1737 851 952 Email: info@globalbusinessmedia.org Website: www.globalbusinessmedia.org Publisher Kevin Bell Editor Tom Cropper Business Development Director Marie-Anne Brooks Senior Project Manager Steve Banks Advertising Executives Michael McCarthy Abigail Coombes Production Manager Paul Davies For further information visit: www.globalbusinessmedia.org The opinions and views expressed in the editorial content in this publication are those of the authors alone and do not necessarily represent the views of any organisation with which they may be associated. Material in advertisements and promotional features may be considered to represent the views of the advertisers and promoters. The views and opinions expressed in this publication do not necessarily express the views of the Publishers or the Editor. While every care has been taken in the preparation of this publication, neither the Publishers nor the Editor are responsible for such opinions and views or for any inaccuracies in the articles.

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Next-Generation Heave Compensation for Maritime and Offshore Applications

Bosch Rexroth BV

Introduction Passive and Active Heave Compensation Next Generation Solution: Electric Active Heave Compensation EAHC Next Generation Solution: Control Platform Next Generation Solution: Energy Recovery

Under Pressure: How Tight Profit Margins Govern the Introduction of New Technology

Tom Cropper, Editor

The End of Easy Oil The Fight for $100 per Barrel Finding the Next Generation of Drive and Control Systems

Facing the Challenge: New Technology for a New Age

Tom Cropper, Editor

Where Nobody Has Gone Before Energy Consumption Recovering Energy Combined Systems Conclusion

The Pros and Cons of Electrical and Hydraulic Powered Systems

Jo Roth, Staff Writer

Hydraulics Electrics

What the Future Holds

James Butler, Staff Writer

From Hydraulics to Electrical Bigger is Better Saving On Weight Heave Compensation Conclusion

References 16

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NEXT GENERATION DRIVE AND CONTROL SOLUTIONS FOR OIL AND GAS OPERATIONS

Foreword O

IL AND gas companies are being squeezed

The sensitivity of hydraulics to extreme temperature

at both ends. On the one hand the

fluctuations encountered in arctic and tropical

requirements of modern oil exploration demand

environments makes them unsuitable to the deep

more sophisticated and powerful equipment, but

water exploration which will mark most of the new oil

on the other hand the commercial environment is

finds in the future. Equally their efficiency improvements

one where every penny counts.

make electrical systems more sustainable than

These twin forces are pushing existing drive and

hydraulics. However, as Jo Roth discovers, the big

control systems up to and beyond their breaking

question is whether weâ&#x20AC;&#x2122;ll see a complete replacement

point. The next generation of technology will have to

of hydraulics by electrics or if a hybrid system of the

walk the thin line of delivering the added performance

two will be the best way forward.

capabilities, while doing so in a more efficient, more

Also in this report we examine more closely the

sustainable and more importantly, less expensive way.

economic background oil companies are working in

The first article in this Special Report focuses on one

and why it means that the next generation of drive and

of the leading names in this field. Bosch Rexroth are

control systems could be crucial to shaping the future

pioneers in the new technological innovations coming

of offshore oil and gas production.

to market. In their article they will explain the workings of anti-heave technologies, as well as some of the new developments that they are bringing to market to cope with the demands of the new generation of oil rigs. One of those developments is in the movement from hydraulic based rigs to electrical drive systems.

Tom Cropper Editor

Tom Cropper has produced articles and reports on various aspects of global business over the past 15 years. He has also worked as a copywriter for some of the largest corporations in the world, including ING, KPMG and the World Wildlife Fund.

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NEXT GENERATION DRIVE AND CONTROL SOLUTIONS FOR OIL AND GAS OPERATIONS

Next-Generation Heave Compensation for Maritime and Offshore Applications

Tough application, ingenious solution

Exactly

Bosch Rexroth BV

Introduction A wide variety of maritime and offshore applications is being installed on ocean-going vessels and floating platforms. In almost all cases they have to deal with the effect of waves, which generate movements of the vessel in the six degrees of freedom. To prevent structural damage to the load, for instance, when it needs to be carefully placed on the sea bed, some form of heave compensation is employed. The solutions currently available are also used to enable work to be carried out even under severe weather conditions. Over the past decades Bosch Rexroth has invested considerably in advanced systems for heave compensation, which have already proven their value in a great number of projects. The companyâ&#x20AC;&#x2122;s latest developments are brought together in a control platform that enables standard solutions to be deployed for crane and winch drives.

Passive and Active Heave Compensation There are two distinct types of heave compensation: - Passive heave compensation (PHC) -A ctively controlled or active heave compensation (AHC)

Moreover, if required, both types can be combined. A passive heave compensation device acts as a spring device with a predefined (relatively low) stiffness allowing for relative motion while keeping load variations in wires suspending the load within acceptable limits. Passive heave compensation systems normally require no power supply for their operation. Active heave compensation is realized by utilizing actively controlled devices which can operate in various modes depending on the required characteristics. Typically these modes: -M aintain constant vertical position (AHCmode) of a free hanging (suspended) load -M aintain constant tension (CT-mode) to a supported or fixed load Apart from its normal operation, the winch is provided with additional controls to realize the compensation functions. Next to the winch a linear hydraulic actuator or cylinder is incorporated in the rigging arrangement; this cylinder is provided with the necessary controls to realize the compensation functions. In order to safely maintain load position or wire tension and to realize accurate control, the

Bosch Rexroth AG www.boschrexroth.com/offshore

PASSIVE VERSUS ACTIVE HEAVE COMPENSATION

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NEXT GENERATION DRIVE AND CONTROL SOLUTIONS FOR OIL AND GAS OPERATIONS

Apart from its normal operation, the winch is provided with additional controls to realize the compensation functions

AHC solution requires specific control devices and instrumentation: -A motion reference unit (MRU) to measure actual vessel motions in all degrees of freedom -A load sensing device (load-cell or load-pin) to measure actual wire tension

Rotary Active Heave Compensation Lastly, active heave compensation can be accomplished in several different ways, which can be generally grouped into Rotary Active Heave Compensation (RAHC) and Linear Active Heave Compensation (LAHC). The Rotary Active Heave Compensation RAHC solution is based on rotary hydraulic drives providing all functionality for the lifting device. In almost all cases the lifting device is a winch for wire rope (steel, polyester, Dyneema™, etc.) or umbilical lines which are used as hoisting. Especially for offshore winch drives in rotary AHC systems, Bosch Rexroth offers the DS2R electrohydraulic controller with proportional valve. In fact, the controller is an upgrade to the electrohydraulic controller used on the company’s A4VSO and A4VSG hydraulic axial piston components, which function as secondary control units in the Rexroth Active Heave Compensation (AHC) system for offshore winching applications. The controller is fitted directly to the secondary control unit – axial piston equipment that can serve both as a pump or motor to manage effectively variations in torque on winch drives in rotary AHC systems. As part of the overall AHC system, the secondary control unit utilizes either a Rexroth A4VSO (open loop control) or A4VSG (closed loop control) axial piston unit to provide the winch torque control when the AHC system is engaged. The new DS2R controller comes with the Rexroth 4WRPH high-response proportional valve and offers several key engineering and operational advantages, including: •H igh dynamic response, which is crucial in continuously varying wave motion conditions. •P recise, accurate motion so that the loaded winch cable remains continuously ‘idle’ – moving up and down only according to the winch, not the surface wave motion •E nergy efficiency - through better control of hydraulic components, including the ability to use hydraulic accumulators to recover and re-use up to 70% of the secondary control unit’s installed power •M ore reliability and easier maintenance, with a simpler design that eliminates a sandwich filter and is less prone to contamination. In addition, the Rexroth proportional valve included with the DS2R is capable of handling

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HOIST WINCH WITH AHC

a greater range of fluid viscosities and requires less pressure drop to maintain control.

Linear Active Heave Compensation The Linear Active Heave Compensation LAHC solution is based on a linear hydraulic actuator or cylinder providing all functionality related to heave compensation of the lifting device. There are two types of applications: 1. T he cylinder arrangement acts directly on a structural arrangement (e.g. boom or lever) of the lifting device, while the lifting operation is performed by a normal hoist winch 2. T he cylinder arrangement operates in

BOOM WITH AHC (ACTUATED BY CYLINDER)

combination with a winch, which provides for the normal hoisting functions and also accommodates for the wire rope storage (on the winch drum). In almost all cases hoisting is done using wire rope or umbilical lines.

AHC CYLINDER RIGGING ARRANGEMENT

Combined Passive and Active Heave Compensation In a number of applications both passive and active heave compensation are applied to: –A ccount for large loads: the passive compensation accounts for the static part of the load, thus reducing the installed power requirement. – I ncrease accuracy: the active compensation accounts for the required compensation accuracy using measured vessel motions as a reference.

NEXT GENERATION DRIVE AND CONTROL SOLUTIONS FOR OIL AND GAS OPERATIONS

Tough application, ingenious solution

The passive compensation is mostly realized using linear hydraulic actuators or cylinders, while the active compensation can be achieved by using a separate active controlled winch or combining passive with active controlled linear actuators.

rotary active heave compensation RAHC concept is very feasible and can be realized without major development effort. Currently, design concepts are being worked out and, with the development of the standard control platform, this will be accounted for.

Next Generation Solution: Electric Active Heave Compensation EAHC

Next Generation Solution: Control Platform

Beside heave compensation using hydraulic drives, new opportunities occur by applying electric drives for active heave compensation. The principle of frequency controlled electric drives has great similarity to hydraulic secondary controlled drives: they are sometimes referred to as electrical secondary controlled drives. The illustration below shows that the DC-Bus with a constant voltage has the same function as the constant pressure circuit â&#x20AC;&#x201C; they function as the common power supply. Like the secondary controlled drive, the frequency controlled electric drive is connected to this common power supply and the common power supply can accommodate multiple drives. Given the resemblance of both principles, it is to be expected that an electric version EAHC of the

Bosch Rexroth recently developed a standardized control solution, which is suitable for both simple and complex winch and crane drives. Engineers can create fast and error-free designs, and, moreover, the integrated safety means that they easily comply with the requisite safety level. They can also take advantage of the modular design and the fact that Bosch Rexroth has employed only proven techniques and technologies, even when it comes to active heave compensation (AHC)!

Exactly

Software Concept The modular approach enables customers to keep the same control system and minimize maintenance and training effort. Differences in control parameters, sensor support and communication interfaces are kept to a minimum,

across technologies with certified components for unique offshore projects as well as for series equipment: Always safe, reliable and robust. Ideal solutions and an ideal partner for you and your operations.

Bosch Rexroth AG www.boschrexroth.com/offshore

STRONG RESEMBLANCE/SIMILARITY BETWEEN EAHC AND RAHC

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NEXT GENERATION DRIVE AND CONTROL SOLUTIONS FOR OIL AND GAS OPERATIONS

The modular approach enables customers to keep the same control system and minimize maintenance and training effort

even though the actual drive system might be completely different. The software supports hydraulic drives with primary control (pump side control, constant or variable displacement motors), secondary control (constant pressure system with swivel angle control on the motors) as well as electric drives. For all drives, energy management is also taken into account, and simulation models exist to verify the drive system will reach the required performance within the given power constraints. The software can be used for simple winches without AHC and a single motor up to large winches with many motors and redundant sensors. A large set of tested and proven technology functions are available, including active heave compensation, constant tension, automatic load takeover, a function for maintaining sufficient tension in the hoisting cable when lowering a load in the water and a function whereby the hoisting cable is first carefully brought under tension before it moves the load at a higher speed (otherwise the latter might ‘jump’ if the speed is too high.)

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In addition, a function block is available for protection against overloading of the crane. The last function is addressed both automatically in the software and manually using dedicated hardware (AOPS and MOPS). Optional functions include ready-made hydraulic power unit (HPU) handling and monitoring, a signal processing library for low cost motion reference unit implementation (under development) and a concept for synchronizing winches (to each other or to external movements). The system functionality can be extended by the customer – for that a full set of PLC features and motion control features (for both electric and hydraulic drives) is available.

Flexible hardware While the software is essentially identical across the board, the control hardware is available in different variations to provide maximum flexibility for the customer. For stand-alone hydraulic winches, we offer a cost-effective and extremely compact integrated control system for the HPU and a single winch drive. This solution provides analogue and digital I/O, closed loop axis control and integrated safety functions, such as a 2-channel stop function up to Pl-e. It provides the engineer with a control solution that uses proven components and technologies, and additionally solves the problem of too many and unidentified interfaces. For larger systems, including multiple winches or complete crane functions, Bosch Rexroth offers a modular and powerful PLC and motion control for DIN rail mounting called XM22. It includes the same functions described above, but adds modular extensibility for controlling multiple winches (or other electric or hydraulic axes) and a large selection of field bus interfaces (master and slave supported): Sercos 3, Profibus, Profinet, Ethernet/IP, Modbus/TCP, etc. As an add-on, a safety PLC (SIL3) can be integrated. With its larger memory and excellent diagnostics and data logging functions (more than 100 channels can be

NEXT GENERATION DRIVE AND CONTROL SOLUTIONS FOR OIL AND GAS OPERATIONS

recorded at 1ms resolution), it is ideal for customer specific extensions. Last but not least, a DIN rail mounted motion controller for a single hydraulic winch (primary or secondary control) is also available.

Next Generation Solution: Energy Recovery With respect to energy recovery for heave compensation systems, the focus is on storage devices with typical charging times of 2,5 to 15 seconds (half of typical wave period). One of the possibilities is using a fly wheel: Flywheels: –C an be used in both hydraulic and electric drive systems – Cover a wide range of cycle periods –B ecome of interest for installation with high power demands (more than 500 kW) For hydraulic systems, the idea is to use flywheels in hydraulic drive systems instead of hydro pneumatic accumulators. The concept is based on the integration of a variable displacement axial piston unit into the constant pressure circuit of a hydraulic drive system. The flywheel concept consists of a steel flywheel and is designed for frequent and high power fluctuations as occur in cyclic operating applications such as heave compensation. A smart computer controlled energy management system ensures a timely and accurate response to energy supply and demands. Small accumulators are installed to deal with rapid power transients which cannot be dealt with by the flywheel. The same principle can be applied to cyclic operated electric drives. Here kinetic energy is stored in a flywheel that is directly coupled with a variable speed electric motor. The energy is transferred through the DC-bus. Capacitors are installed to deal with rapid power transients which cannot be dealt with by the flywheel. Especially for high power demands, the flywheel solution will certainly result in reduction of costs (up to an estimated amount of 60%) by: –R eduction of installed power and therefore investment costs –R eduction of energy consumption and therefore fuel costs –R eduction of emission of exhaust of prime mover.

Tough application, ingenious solution

Motion Compensated Platform Barge Master The Barge Master concept is a motion compensated platform developed by Barge Master in close collaboration with Bosch Rexroth. It is intended as a solution to the problem of vessel motion during crane operations. Because of the amplifying effect of the length of the boom of a crane, relatively small levels of vessel motion result in much greater motion at the tip of the boom end therefore of the load carried by the crane. ‘Workability’ is therefore strongly influenced by weather and sea state, including swell, which has an especially significant impact on the motion of supply vessels and crane barges leading to work being interrupted, adding to the time it takes to complete a project, and hence to cost. The Barge Master concept uses motion compensation techniques of a type that were developed in recent years and applies them to platforms to be used on flat-top barges and supply vessels. These platforms provide a stable base for cargo during vessel-to-platform transfers – they can also be used as a steady foundation for a crawler crane engaged in lifting operations. Designed as a low-cost, high-performance alternative to existing offshore and near-shore lifting equipment, such as jack-up barges, Barge Master has an internal hydraulic mechanism that measures waves and swell conditions and compensates for them so that the platform remains steady. The first platform has a capacity of 700 tons in which the hydraulic pumps are powered by three 510 kW Rotor electric motors. Further, the engineers used standard flat-top barges of 60 x 20 m of 90 x 30 m with a standard crawler crane with a maximum lifting capacity of 400 – 600 tons. In order to prevent the platform carrying a crane from moving, six degrees of freedom are compensated by restraining two translations (surge and swell) and one rotation (yaw) of the barge, using traditional anchors or a dynamic positioning (DP) system. The remaining three degrees of freedom – one translation (heave) and two rotations (roll and pitch) are compensated by the trio of hydraulic actuators on the Barge Master. By measuring heave, roll and pitch and controlling the actuators supporting the platform to produce counteractive motion, the platform is kept stable. Custom built Barge Masters can be developed and built according to client-specific requirements. Basically any crane on a vessel can be mounted on a Barge Master. The entire structure of the Barge Master and the ancillary equipment can be transported in 10-15 containers depending on the size and capacity of the equipment.

Exactly

Bosch Rexroth AG www.boschrexroth.com/offshore

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NEXT GENERATION DRIVE AND CONTROL SOLUTIONS FOR OIL AND GAS OPERATIONS

Under Pressure: How Tight Profit Margins Govern the Introduction of New Technology Tom Cropper, Editor Modern oil rigs must drill deeper and faster; however is the money there to justify the expense of innovation?

While finding oil in the first place is becoming more challenging, the economic outlook for the industry is uncertain

HE OIL and gas industry is continuously researching new technologies and innovations. However, it can be cautious in how it adopts them. Before it accepts any new innovations it must ask itself three questions: will it work, how much does it cost and is it worth the price? Those questions become ever more important given the economic background within which companies are working. They find themselves under attack on two fronts. In order to maintain production they have to exploit more remote and hard to reach sources, tap smaller fields and employ unconventional techniques. All of these cost money and require additional equipment; unfortunately with the oil price in the doldrums – at least in the short term – they are finding it difficult to do so in a sustainable way.

The End of Easy Oil The oil and gas industry has been facing an uncomfortable truth for some time now: the age of ‘easy oil’ is over. Oil production in the majority of countries has now peaked with some of the oldest and most established oil fields having showed continuing decline over the past ten or so years. Estimates suggest that in little more than a century of oil exploration, we have now depleted around half of the world’s overall reserves. Accessing the half that remains in the Earth’s crust is no easy matter. Much of it is locked deep in tight rock formations or can only be found by going into areas of the world which had previously been considered unreachable. This involves drilling at extreme depth and in environments which are far more hostile than any which have been faced before. This places a strain on operating equipment, and increases the likelihood of failure. 8 | WWW.OFFSHORETECHNOLOGYREPORTS.COM

The alternative is to maximize yield from existing sources. This can be done by enhanced techniques such as horizontal drilling, which exposes more of the reservoir, and gas injection which forces heavy oil to the surface. These approaches have extended the operational lifespan of many of the world’s oldest oil fields well beyond their original expectancy, while the growth of shale gas has increased the flow of oil onto the open market.

The Fight for $100 per Barrel While finding oil in the first place is becoming more challenging, the economic outlook for the industry is uncertain. Long term thirst for oil is expected to be high thanks to surging demand in countries such as China and India. However, in the shorter term, a sluggish economy means the outlook is less promising. Estimates about the growth in demand for oil fell progressively throughout 2014 which has exerted a downward pressure on prices. Experts believe that a global oil price of $100 per barrel is required in order to ensure oil can be extracted in a profitable manor. However, as of October 2014, Brent Oil stood at closer to the $80 mark1. Oil companies therefore come under pressure on two fronts. It is more difficult and therefore more expensive to extract oil, while the commercial environment in which they are operating is becoming more marginal. New technologies are therefore required which have a good chance of addressing both challenges.

Finding the Next Generation of Drive and Control Systems The move into deeper water has sparked the development of new, more powerful and more sophisticated offshore support vessels and platforms capable of lifting unprecedentedly

NEXT GENERATION DRIVE AND CONTROL SOLUTIONS FOR OIL AND GAS OPERATIONS

Tough application, ingenious solution

high loads. Macgregor, for example, has recently unveiled its plans for a 900 ton active heave compensated crane2 which they say is the largest of its kind yet built. Operating at depth also brings equipment into contact with hazardous conditions such as extreme temperatures and rough seas. These require more sophisticated heave compensation systems which is why we have seen the move away from passive heave compensation (PHC) systems into active heave compensation systems (AHC). PHV use a spring device with a predefined stiffness to compensate for the motion of waves. They require no power so are inexpensive to run, but are limited in their capacity. AHC units have a far greater accuracy and can cope in more extreme environments. Temperature fluctuations, meanwhile, take existing drive and control systems beyond their original operating parameters. The icy conditions found in the arctic, for example, go well below the toleration threshold of hydraulic powered systems. The solution being sought by many operators has been to switch towards electrical systems or a hydraulic/electric hybrid system which is capable of maintaining continuous function in all temperature and weather conditions. Electrical systems also have potential in another key issue â&#x20AC;&#x201C; cost. Keeping this under control will be a major challenge. The energy efficiency of an electrical system versus hydraulics can be

key in keeping energy consumption under control. This also helps rigs maintain their emissions, as pressure is piled on them from governments and the public to control their impact on the environment. Cost controlling measures can also be crucial in opening up those marginal fields considered too small to be economically viable. When oil reserves in one area are too small or too difficult to extract, major players such as Shell, Exxon and BP are moving on and leaving the field open to smaller operators such as NGP Capital Management, ATP Oil and Gas and Whiting Petroleum, who are able to score big on fields shunned by the likes of Shell, BP and Total. NGP Energy, for example, has gained 31% a year since 1988 by squeezing those older fields deemed too uncommercial by larger producers3. In doing so they hope to unlock trillions of dollars in previously undiscovered sources. Doing this requires more mobile and flexible drill ships which can exploit oil in one area for a defined amount of time, before moving onto others. These enable companies to exploit oil at a fraction of the cost of installing a large oil rig. These are, then, tough times for the oil and gas market as they seek to balance those two seemingly incompatible goals: doing more with less. Given the variety of conditions being faced, there is no one size fits all solution. Operators need to identify ways in which they can make this new technology work for them.

Exactly

Bosch Rexroth AG www.boschrexroth.com/offshore

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NEXT GENERATION DRIVE AND CONTROL SOLUTIONS FOR OIL AND GAS OPERATIONS

Facing the Challenge: New Technology for a New Age Tom Cropper, Editor

How efficiently oil companies use energy will be crucial to whether or not they will be able to access the vast reserves of oil which have yet to be tapped

According to various reports, Britain’s oil reserves could be far greater than originally thought

HERE IS a saying: necessity is the mother of invention. The oil and gas industry certainly has plenty of both. It needs to access untapped oil and gas reserves in more challenging areas of the world. To do so it requires substantial technological innovation. But while innovations are appearing all the time, it remains unclear whether this oil can be accessed in a way which makes the business affordable. Key to doing this is how they use energy, which is why the manner in which they are powered and how much they consume is almost as important as what they can do.

Where Nobody Has Gone Before According to various reports, Britain’s oil reserves could be far greater than originally thought. A recent investigation by Oilandgaspeople.com found that there could be double the amount of oil previously estimated lying off the West Coast of Scotland4. The North Sea, meanwhile, could possibly hold an estimated 24bn barrels of oil5, all of which could reverse the recent downward trend on oil production. What’s happening in the North Sea is mirrored elsewhere in the world, where billions of barrels of oil are thought to lie in deep water, locked in rock or previously unreachable parts of the world such as the arctic. However, accessing these reserves will require new advances in drilling technology. These will have to contend with a difficult environment in which they are expected to outperform previous technologies, but to do so in an environmentally friendly and cost efficient way.

Energy Consumption The economic demands of oil exploration are seeing oil companies moving into deep water and operating in conditions they would previously have left alone. Operating at depth requires new machinery and more power output. Harsher environments also increase the risk of damage or breakdown resulting in costly downtime for repair. All of these things run up the cost, making 10 | WWW.OFFSHORETECHNOLOGYREPORTS.COM

extreme condition oil exploration a commercially marginal proposition. In an ideal scenario, oil rigs would only drill in calm ocean conditions. However, every hour spent idle represents an impact on a company’s bottom line, so they are being pushed into operating in ever more demanding conditions. Some of the most advanced drive and control systems are enabling rigs to continue working in wave conditions of ten meters or more. Doing so comes at a considerable price. According to Bosch Rexroth, operating a 50 ton knuckle boom crane will consume over two mega-watts of electricity an hour6. Considering the pressure being placed on operators to cut emissions, together with the purely financial implications of such high running costs, companies are making energy efficiency a number one priority.

Recovering Energy As outlined later in this report, many drilling companies are switching from hydraulic powered operating systems to electrical. The move is sparked in part by a need to be more energy efficient but also by the temperature sensitivity of hydraulic equipment. Electrical systems are able to operate more efficiently in high and low temperatures, but they have one substantial drawback. Hydraulic systems use gas powered accumulators to harvest and store energy. This can be put back into the system for temporary boosts, but it’s much more difficult to achieve this with electrical components. These can store energy, but only by using large, heavy battery packs. Some innovations exist to combat this. Writing for OneDigital, Herman Stolle and Lee Screaton suggest one potential area is to use technology which is already familiar to millions thanks to its use in Formula 1 – Kinetic Energy Recovery System (KERS). “While it has not been achieved to date,” they write, “it might well be possible to use KERS to mimic this reinjection method for electrical systems, which

NEXT GENERATION DRIVE AND CONTROL SOLUTIONS FOR OIL AND GAS OPERATIONS

Tough application, ingenious solution

could widen the acceptance of electric drive for high-power AHC systems.”7 Another solution they highlight is improvements in battery storage – another major drawback of electrical AHC systems. With deck space on board an oil rig at a premium, batteries for electrical systems are heavy and cumbersome. This technology has been making the transition from cars into the oil and gas industry and raises the possibility of having batteries placed on the seabed rather than occupying highly valuable space on board the rig.

Combined Systems However, because such technology remains at an early stage, hydraulics still retain a key role for active heave compensation systems – either as the sole method or in combination with an electrical system. The solution employed by Bosch Rexroth has been to use so called dynamic systems. Their system uses a secondary controlled drive which senses the torque at the winch to create a system which is highly responsive and only uses the minimum amount of power at any one time. They can also work to store energy using a bank

of hydraulic accumulators. These store energy in a nitrogen filled bladder within a steel shell. When fluid under pressure fills the accumulator it compresses the gas. When this pressure falls, the oil within the accumulator is available to provide pressure and high flow rates back into the system, which not only saves energy but increases the overall lifespan of the system. When working in rough seas, the motion of the vessel creates energy which can be absorbed by these accumulators and fed back into the system. Bosch Rexroth state that this allows it to recover up to 75% of the energy used, which results in significant reductions in power requirements.

Exactly

Conclusion Innovations in drive and control systems and, in particular, heave compensation, have made great strides in recent years, not only in upping capacity but using energy in a more cost effective and efficient way. The gains they have made possible are crucial in enabling oil companies to push the envelope ever further in how they exploit new oil sources. The major challenge now is to decide which technologies and which solutions are the best fit for individual operations.

solutions in cooperation with you. From the first idea through to commissioning and lifelong service we realize package solutions across technologies with certified components for unique offshore projects as well as for series equipment: Always safe, reliable and robust. Ideal solutions and an ideal partner for you and your operations.

Bosch Rexroth AG www.boschrexroth.com/offshore

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NEXT GENERATION DRIVE AND CONTROL SOLUTIONS FOR OIL AND GAS OPERATIONS

The Pros and Cons of Electrical and Hydraulic Powered Systems Jo Roth, Staff Writer In order to cope with more hazardous environments, many operators are replacing hydraulic powered systems with electrical – but what are the pros and cons of these two systems?

The downside of hydraulic power, though, is that it is highly sensitive to changes in temperature

HE END of the age of easy oil is forcing companies to be more inventive in terms of where they are willing to go to find oil and the conditions they are operating in. Rigs are looking to drill deeper, in more remote areas and in all weathers. This puts a strain on drive and control systems which need to be more powerful, more energy efficient and capable of withstanding a whole range of new and demanding conditions. The harsh reality of modern day exploration is that some equipment which has been used for decades is no longer suitable for the job, which is why many operators are now switching from hydraulic powered to electrical powered drive and control systems. However, electrical systems do not have all the answers, which means considerable uncertainty remains over which one is the best to use.

Hydraulics Traditional heave compensation systems have been powered by hydraulics. The earliest of these systems relied on hydraulic cylinders to calculate the heave caused by the movement of the waves and power cranes. Gas accumulators can be used to store energy, which enables response to extreme demand levels without increasing the size and power output of the pump, and to cope with temporary power demands. The downside of hydraulic power, though, is that it is highly sensitive to changes in temperature. Changes can alter the makeup of the hydraulic fluid which, in turn, harms the performance of the system. This presents major challenges when rigs venture into either extremely warm areas or, more particularly, the extreme cold of the arctic. Systems can often fail due to a contamination of the oil through water and floating debris. 12 | WWW.OFFSHORETECHNOLOGYREPORTS.COM

They also require an extremely large Hydraulic Power Unit – (HPU), which again has implications for space, and the working environment. This unit can, if necessary, be moved to a less populated part of the rig, but taking it any significant distance from the system requires considerable piping which again adds clutter to the already crowded platform surface.

Electrics Hydraulic systems, therefore, seem to have come to an evolutionary dead end. The modern market is placing demands on them, in terms of energy consumption and durability that they are simply unable to meet. The solution being employed by the industry is to switch from hydraulic to electric based systems. These are firstly much less sensitive to temperature changes than their hydraulic counterparts, meaning they can function in extreme cold and are less liable to require maintenance. They also contain no toxic fluid, which makes them cheaper to run and safer from an environmental point of view. With governments around the world pressurizing the oil industry to reduce the threat it poses to the surrounding ecosystem, this represents a major plus. Moreover electrical systems are more energy efficient. Hydraulics typically offer efficiencies in the region of 70%, compared with electrics which can be up to 85% or 90%, making them ideal for environments which will have heavy duty requirements; such as powering mud pumps, draw works and top drives. Greater efficiency means improved productivity and reduced power consumption – something which has benefits both from cost and environmental perspectives.

NEXT GENERATION DRIVE AND CONTROL SOLUTIONS FOR OIL AND GAS OPERATIONS

Tough application, ingenious solution

However, making the transition is far from straightforward. Any new technology or equipment represents a significant investment and risk and there are many areas in which electrical power is struggling to match the performance of hydraulics. The biggest problem is storing energy. This is made possible only with the use of large and extremely heavy batteries which takes up space and represents an environmental hazard. In comparison, hydraulic actuators have a much better power to size ratio which means a smaller and lighter motor. Given the tight operating environment of oil platforms, this represents a major benefit versus electrical systems. The hydraulic cylinder has also proved difficult to replace with an electrical counterpart. There are possible developments which can address these issues. Kinetic Energy Recovery and System (KERS) technology has the potential to harvest energy using electrical power. Batteries are also becoming more sophisticated and capable of producing more power from a smaller footprint. Some possibilities exist in using lithium batteries which could be submerged on the sea bed,

providing power, without taking up space on board the platform. These ideas, however, are still in the developmental stage, which means any operator must balance the conflicting pros and cons of these two systems. Hydraulic power has a clear advantage in that it can harvest and store energy using gas powered accumulators rather than the heavy and bulky electrical cylinders. However, extreme operating environments often push hydraulic systems up to and beyond their operating limits. Cold weather can cause malfunction in the system, leading to costly down time for repair. Equally, the use of toxic hydraulic fluids represents a threat to the environment which, with the pressure on to transition to a zero emissions oil rig, represents an increasing problem, especially given the delicate ecosystems oil rigs are increasingly being asked to work in. The decision will, in large part, depend on the specific requirements of any drilling operation, and while fully electrical systems may well one day become the norm, many others will opt for a compromise of the two â&#x20AC;&#x201C; a hybrid system where electrics supplement rather than replace hydraulics.

Exactly

Bosch Rexroth AG www.boschrexroth.com/offshore

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NEXT GENERATION DRIVE AND CONTROL SOLUTIONS FOR OIL AND GAS OPERATIONS

What the Future Holds James Butler, Staff Writer Drive and control systems for offshore oil and gas rigs are developing quickly, but what does the future hold for the next generation of technology

Perhaps one of the more important cost factors comes in the steel wire rope used on the cranes

HEAP, EASY oil has come to an end which means deep sea, hazardous environment exploration is undergoing something of a boom. To cope with the additional demands being placed upon them, drive and control systems for platforms and oil support vessels are having to evolve rapidly. We’ve already seen the move from hydraulics to electrical systems, larger cranes, more sophisticated software and energy recovery systems. This article will look at the many ways in which drive and control systems are changing and what the next generation might hold.

From Hydraulics to Electrical The need to drill in more extreme environments means hydraulic control systems are often no longer suitable. As such, rigs are increasingly migrating onto electrical systems. These are less vulnerable to temperature fluctuations and contain no toxic or hazardous fluids to contaminate the ocean. However, the electrical driven power rigs require substantial space for batteries, and find it difficult to recover energy in the same way as can hydraulics. Because of this, many of the systems opt for a combination of both to maximize performance and efficiency.

Bigger is Better To cope with the additional demands being placed upon them, cranes are bulking up. Companies are now producing Active Heave Compensation cranes with a capacity for 500 tons and more. Cargotec Macgregor, for example, is currently working on what they say is their largest Active Heave Compensation crane ever for a vessel which is due to be launched in July 2015. They say it is rated to lift loads as high as 900 tons. “At a time when subsea modules are getting larger and heavier, and operations are being conducted at ever greater depths a sophisticated crane on this scale equips

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the new vessel to meet the ever increasing demands of the offshore construction market,” commented Frode Grøvan, Director, Sales and Marketing for Advanced Load Handling. The crane will be equipped to work in ultradeep water installation, pipe laying, cable lay and top side construction support. Size is at the heart of one of the most powerful and advanced vessels to have taken to the ocean in recent years. The Pieter Schelte, the newest addition to the fleet for Swiss based Allseas Group, has been described by Business Week as being a cross “between a ship and a giant highly dexterous robot.”8 It is able to transport and install massive structures all in one piece thanks to the world’s largest mobile lifting system. Working in conjunction with Bosch Rexroth they have created a Topside Lifting System (TLS) capable of plucking up the top sides of platforms with a weight of up to 48,000 tons. In doing so, it means workers no longer have to disassemble the structure into component parts while at sea – a process which is costly, time consuming and hazardous. Instead it can transport and install the structure all in one piece. It is a ground-breaking development for the industry as Ron van den Oetelaar, Allseas Project manager explains. “No comparable system has ever been created before, making this an exciting task, even for our experienced engineers,”9. With bigger cranes, come bigger support vessels which, in turn, are delivering larger installations are greater depths and in more severe environments. Everything is being scaled up and, in theory, the only limiting factor is cost – and that is considerable. Large cranes consume huge amounts of power in order to operate, which places upward pressure on operating costs and, in the final analysis, end prices. Controlling energy consumption is a major consideration

NEXT GENERATION DRIVE AND CONTROL SOLUTIONS FOR OIL AND GAS OPERATIONS

Tough application, ingenious solution

Exactly

going forward, which is why weâ&#x20AC;&#x2122;re seeing the development of more sophisticated and flexible control options that can vary the amount of power being used to keep consumption to a minimum.

Saving On Weight However, perhaps one of the more important cost factors comes in the steel wire rope used on the cranes. Larger cranes require rope with a greater diameter, which naturally represents a major expense. Likewise, operating at extreme depths will require more rope and will also increase the weight penalty of the wire. As depths plunge below 2,000 meters this becomes a significant cost and for many years the industry has been investigation alternative solutions. One way to reduce the weight penalty is to use a material which is as near to being naturally buoyant as possible, such as fiber wire. This much lighter material massively reduces the weight penalty felt in comparison to traditional materials, resulting in significant savings in deep water installations. However, it comes with a number of problems. First, fiber wire has a lower axial stiffness than steel wire, and its lightness also creates a major difference between the deployment of a load and recovery of an empty hook. It may also require the creation of a new handling system, which again requires more work and expense.

Heave Compensation Heave compensation systems will continue to show even greater development over the next few years, as shown by the new Ampelmann vessel10 being launched by Barge Master in 2015.

From oil rigs 100 meters above sea level to equipment 5,000 meters

Working with partners including Bosch Rexroth they have developed a system which is able to compensate for movement in all directions. Where this vessel will be unique will be its ability to compensate for pitch as well as heave, which will mean it is able to transfer heavy loads in waves of up to three meters in height.

below: In the harsh environment of offshore applications, technology must always be safe and reliable. Being the most experienced system partner in the world, Rexroth develops tailored drive and control solutions in cooperation with you. From the first idea through to

Conclusion This is a time of considerable energy and development. The demands being placed on oil platforms and vessels have grown, so the technology they come armed with has to develop accordingly. As a result, manufacturers and suppliers are devoting enormous amounts of time and energy into developing highly sophisticated, bigger and better systems to increase the accuracy and capacity of heave compensation systems. These can lift bigger loads, cope with worse conditions, and operate at a reduced cost, producing multiple benefits for operators in all directions.

commissioning and lifelong service we realize package solutions across technologies with certified components for unique offshore projects as well as for series equipment: Always safe, reliable and robust. Ideal solutions and an ideal partner for you and your operations.

Bosch Rexroth AG www.boschrexroth.com/offshore

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References: Brent crude drops below $86 per barrel: http://www.theguardian.com/business/2014/oct/27/brent-crude-oil-price-drops-goldman-sachs-forecast

Offshore cranes get bigger and more sophisticated: http://gcaptain.com/offshore-cranes-bigger-sophisticated/

Tapping older fields for profitable leftovers:

http://royaldutchshellplc.com/2006/07/04/royal-dutch-shell-plc-com-tapping-older-oil-fields-for-profitable-leftovers/ Scottish West Coast Untapped oil reserves could be worth trillions:

http://www.oilandgaspeople.com/news/1039/scottish-west-coast-untapped-oil-and-gas-reserves-worth-trillions/

North Sea Oil, facts and figures: http://www.bbc.co.uk/news/uk-scotland-scotland-politics-26326117

Active Heave: How to accumulate more savings: http://tiny.cc/ae2jox

Heave Compensation improves offshore lifting operations:

http://www.oedigital.com/engineering/item/6363-heave-compensation-improves-offshore-lifting-operations

The Worldâ&#x20AC;&#x2122;s Biggest Ship? http://www.businessweek.com/articles/2014-10-22/the-pieter-schelte-maybe-the-biggest-ship-definitely-the-niftiest

Record breaking Allseas vessel lifts offshore platforms in one piece: http://www.boschrexroth.com/en/xc/company/press/index2-1623

A special focus on the new pioneering walk to work vessel: http://www.wagenborg.com/our-stories/the-shape-of-innovation

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