FIBRE FOR DEEP OFFSHORE OIL & GAS OPERATIONS

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1 FIBRE FOR DEEP OFFSHORE OIL & GAS OPERATIONS Antoine Lecroart, Ronan Michel (Alcatel-Lucent Submarine Networks) Alcatel-Lucent Submarine Networks, Route de Villejust, Nozay, France Abstract: Oil & gas operators need to develop offshore fields that are further from shore and in deeper waters. Fixed structures cannot be used anymore and the complexity of the new floating assets that are engineered and deployed to operate these remote reservoirs is increasing. The new platforms or vessels are more and more dependant on secure communications as the major oil & gas companies are developing integrated operations relying heavily on expertise centres based onshore. Fast and reliable broadband communication links between the shore-based hubs and the offshore assets are becoming critical for these new intelligent fields. This paper describes overall solutions to address these needs. It reviews available technologies for connectivity and communications needs suited to deployment in offshore environments. The unique advantages of submarine cables is developed, as well as their integration in the complex project-driven offshore development approach, while respecting the Engineer Procure Install and Commission (EPIC) scheme broadly used in the oil & gas industry. The necessary planning steps at the engineering phase to ensure extensibility over time to serve possible geographical extensions of the offshore assets are also discussed. 1 INTRODUCTION Exploration and production of offshore fields is evolving and makes increasing use of various modes of communications. With the advent of intelligent fields, the trend is to gather increasing amounts of data from the subsea environment in the field and to convey them to competence centres where the expertise is gathered to take decisions that will improve the processes in the field. Many oil & gas companies are establishing these operations centres in their hubs where technical expertise is normally located avoiding onerous transportation, relocation and associated costs. Of course telecommunications from the field to these centres is now becoming critical but solutions exist to make them both efficient and dependable with a choice of different technologies, listed in Table 1 below. Table 1 : Offshore Communications Technologies VSAT offers ubiquity for the connection but its cost grows rapidly with the capacity. Satellite connections are sensitive to bad weather and are prone to latency. Microwave allows more bandwidth and recent IP based products seem less sensitive to propagation issues. However, their limited reach is such that it is difficult to access the deepest fields far away from shore. Wimax could be used in hub and Copyright 2010 SubOptic Page 1 of 6

2 spoke architectures close to a main facility to reach temporary rigs or service vessels around the area. The technology of choice for the main offshore facilities ought to be fibre. Submarine cables are not as easy to install as the radio systems and come with a different price but they provide almost unlimited bandwidth with the lowest delay. Ring or loop architectures provide the necessary redundant paths to shore allowing traffic availability to be better than 99.99%. Furthermore, fibre solutions developed for the world s international telecommunications links are already fully qualified and exhibit high reliability performance. 2 DEEP OFFSHORE FIBRE SOLUTIONS The field proven submarine cable solutions for the international telecommunication networks are characterized by high capacity optical fibre transmission (hundreds of Gbit/s), DC power transmission (tens of kw), and high quality, highly redundant configurations for fault free operations over 25 years. POP DRY PLANT Terminal Equipment Land Cable Cable Station Network Management Power Feed Equipment Cable WET PLANT Branching Unit Repeater, Equalizer Survey, Lay, Maintain Figure 1 : Repeatered System Schematic This technology can be enhanced for the oil & gas environment to achieve offshore connectivity. Trans-oceanic or Regional connectivity Deep water connectivity Figure 2 : Offshore Fibre Communications The solutions for deep offshore consist of adapting the traditional shore-to-shore telecommunication application so that it can cope with different types of offshore assets such as a fixed platform or floating assets such as TLP, SPAR or FPSO. Ring or loop architectures provide the basis for a highly reliable backbone connecting each asset with its own spur thanks to the use of Branching Units (BUs). The system is designed to allow the platforms to be independent and also limits the number of risers per asset to one, compared to two for a simple daisy chain. In some cases where satellite backup is not an option such as the high latitude areas, duplicated last miles may be required for each floating asset. 3 LAST MILE ARRANGEMENTS For the last mile connection, a dynamic riser is required to access floating assets while a simple J-tube may be sufficient for fixed structures in shallower waters. Alcatel-Lucent s dynamic riser is based on a standard submarine optical cable core with a specific armouring where two layers of armour wires are used with different numbers and sizes of steel wires. The two layers are cabled with opposing pitches so that there is no residual torque on the cable when it is installed. Copyright 2010 SubOptic Page 2 of 6

3 Figure 3 : ASN Dynamic Riser Design This torque balanced cable is the basis of the dynamic riser arrangement which depends on the local meteorological and sea conditions, the specific configuration of the I-Tube used, of its surroundings and the Response Amplitude Operators (ROAs) of the floating asset. Following complex calculations, the riser may be used in a simple catenary arrangement or with additional submerged buoys to obtain a lazy-s configuration. Bend limiters and/or bend stiffeners may also used to complement the riser arrangement. Added complexity may come from the use of Fibre Optic Rotating Joints (FORJs) as some FPSOs adopt the turret architecture allowing the vessel to rotate freely. In some cases, the turret is designed to be detached from the vessel itself allowing the vessel to evacuate should a major hazard be forecast in the area such as a hurricane or a drifting iceberg. It is important to use FORJs that minimise the variation of some key optical parameters as they rotate, such as the optical attenuation or the return loss. The FORJs could also limit the length of the overall last mile arrangement as most of them do not accept very high optical powers. This may prevent, for instance, the use of high power boosters or Raman sources in the optical design of the spur to the rotating asset. Another approach is to equip some of the many umbilicals with fibres and allow the last mile connection to take place subsea with a combination of wet mate connectors, subsea optical jumpers and umbilical termination assemblies. In this case, a special cable termination is provided and optical connections can be performed subsea by an ROV handling the jumpers made of flexible hose and wet mate connectors. Both the separate riser and combined umbilical approaches are valid and will solve the last mile issue adequately, provided enough communication is established with the project team in charge of the Subsea Umbilicals Risers and Flowlines activities (SURF) of the assets. 4 PLANNING AHEAD The other big difference with satellite is the necessity of detailed planning before installing a fibre network as a length of cable on the seabed cannot be moved as easily as a satellite antenna atop the living quarters of a platform or FPSO. A fibre network is an investment for 25 years. Although it can evolve and be extended, it is much better if its possible extensions are actually planned from day one. This planning phase requires the knowledge of how the field will evolve in time and whether new structures (topside or subsea) will be coming in the future. This knowledge is in general very sensitive for the operating oil & gas companies and is not something they are inclined to share with a contractor. Yet, it is important to know how many last miles will actually be required over the operational phase of the fibre network, what would be the lengths of these spurs and how many Branching Units (BUs) are required whether active and connected or dormant with just a tail of fibres looped back for later pick-up and connection when the asset arrives on the field. Copyright 2010 SubOptic Page 3 of 6

4 5 FIBRE BUSINESS CASE: BUY OR LEASE Fibre links are also very different from satellite links when it comes to the way they can be purchased or leased. The very specific and dedicated nature of the fibre network is such that its hardware cannot easily be re-used for another project or another customer. The relatively high portion of specific marine installation services in the price of a fibre network is also quite different from the installation services for radio or satellite transmission. As such, the traditional approach for a fibre network is the direct purchase where the owner of the network will also maintain and operate it. Clearly, it is the CAPEX model that dominates the fibre business either with single customers or consortia of customers who normally bind themselves through a Construction & Maintenance Agreement (C&MA) at the outset of each project. Operating a fibre network is not very difficult and all the suppliers in the industry include comprehensive hands on training sessions in their offers that allow the owner s personnel to be fully versed in the day to day operation of the network. Remote expertise from the supplier is also available and can be purchased as an additional service. The marine maintenance is a serious issue as any down time of the system may affect the overall availability of the communications. For oil & gas applications, this can impact the operations of the connected assets. Telecom operators have traditionally used Maintenance Agreements to make sure that their cable will be repaired in a given lapse of time. The principle is such that the maintenance provider will provision a number of cableships to guarantee, for a given yearly fee, that a repair vessel can sail in an agreed time after a cable failure has been notified. The yearly fee is normally fixed and does not include the cost incurred for a specific repair campaign. The fee is generally proportional to the actual length of the cable network entering into the agreement. For oil & gas operators, the situation could be different as most of the offshore operations in large basins require a permanent fleet of various services vessels. Local arrangements with the operators of this fleet can allow for a marine maintenance spread for cable repair to be readily mobilized on board an adequate flat deck DP2 vessel for instance. Final arrangements for the marine maintenance are likely to be dealt with on a case by case basis depending on the local conditions for the different fields and the local rules and regulations. The leased service approach may be attractive to some oil & gas operators as it is what they normally deal with when using satellite connections. A number of the major oil & gas companies have also decided to externalize functions related to information technologies and communications as a corporate strategic move. It is understood that tax benefits might be gained by this approach as it limits the amount of immobilized assets. Yet, the business case for a telecom operator who may consider building a dedicated network for oil & gas operators in a given basin does not appear obvious. There will almost certainly be no other customers of the network than the oil & gas operators and no synergies are to be expected by trying to combine the network with another domestic or international cable project. In the end, the telecom operator will simply act as a bank to the oil & gas companies and it may not be economical in the long run for the oil & gas companies to lease the fibre services if they have the cash to directly purchase the network. Using a middleman will not avoid the necessary discussions between the supplier and the asset owner when it comes to operational matters related to the installation of the last miles, including dynamic riser configurations, precise cable Copyright 2010 SubOptic Page 4 of 6

5 route definition, installation procedures, qualification of the vessels, tools and personnel used, operational permits, health & safety, etc. The fibre, in fact, has to be seen as yet another critical element in the busy and complex environment in which it has to be installed. It is naturally part of the SURF package and at some point will have to be dealt with by the SURF experts of the oil & gas company. This tends to indicate that the sensible way to deal with an offshore fibre network is by direct purchase and it is interesting to notice that the recent large scale fibre network in the Gulf of Mexico was acquired in such a way. 6 CULTURAL GAP There seems to be some wariness between the oil & gas industry and the telecom submarine cable industry yet each could benefit from knowing the other better. In the oil & gas industry, Engineer Procure Construct (EPC) or Engineer Procure Install Commission (EPIC) contracts are widely selected as the preferred contracting strategy for pipeline and facilities projects. EPC/ EPIC contracts provide a single point responsibility for all aspects of the project and enable close coordination between engineering design, procurement and construction activities. The EPC/EPIC scope of work will generally be tendered following completion of the Front End Engineering Design (FEED) package for the project. The EPC/ EPIC scope will then include the development of the FEED into a full detailed engineering design prior to procurement of materials and construction. In the telecom submarine cable industry, purchasers sign turnkey contracts with suppliers, encompassing all aspects of system design, manufacture, installation, commissioning and long-term support. Although the EPC/EPIC terminology is not usually applied, there are many similarities with the turnkey contract approach. However, in the oil & gas industry, because the field topologies and the characteristics of the products extracted generally differ, project specific engineering is the norm whereas in the submarine cable industry, a selection of generic products (some of which being slightly modified on a case by case basis) are integrated to create project solutions It is also well known that the oil & gas industry has Health, Safety and Environment high in its priority list and all related procedures are duly documented. Documentation and project management are also two other fields where differences can be seen between the two industries. Yet both are very concerned by technical risk mitigation, both look for best-in-class solutions and both are driven by very high service availability requirements, which in the case of the oil & gas sector contribute to continuity of production and lowering of uplift costs. 7 CONCLUSIONS Although this paper underlines some added complexity of fibre solutions compared to satellite solutions, the true operational benefits of the fibre must also be underlined. It is indeed more complex to deal with fibre rather than satellite and this could explain the relative slowness of fibre introduction in the oil & gas basins. Yet, fibre typically brings an increase by an order of magnitude of the traffic availability, significantly reduces the transmission delay and brings an increase of capacity by three orders of magnitude. Fibre is a true enabler of critical new functions such as remote operations, real time reservoir monitoring and remote control. As such it can affect the heart of exploration & production and results in improved efficiency. Many major oil & gas companies have now set rules imposing fibre connections on all new major offshore assets and it is only a matter of allowing the time for the oil & gas industry to bridge the gap with the submarine telecom industry to adopt Copyright 2010 SubOptic Page 5 of 6

6 and embrace this technology as it has successfully done in other more complex domains. Copyright 2010 SubOptic Page 6 of 6