TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractIn the current climate of high oil & gas prices and forecast future shortfall in reserves, it is critical that new technology be implemented to maximize recovery from any suitable reservoir. One of the most promising areas of offshore oil and gas R&D has been the ongoing development of improved reservoir and production monitoring technology implemented using fiber-optic sensors. This paper will contribute new performance data for fiber-optic connection systems and sensor requirements and will document and contrast the various sensor technologies and their capabilities and applications.This paper provides a review of the advancements in fiberoptic in-well sensing technologies and the applications to which they can be applied, set-in context with the importance of optimizing reservoir performance. This is combined with an analysis of the development and qualification of fiber-optic feed-through systems that are a fundamental technology for the installation of in-well optical fiber. This discussion will include design guidelines for feed-through systems and will be supported by case studies for the sensor and feed-through systems proposed for BP Atlantis in the GOM, and BP's West Africa project, Greater Plutonio.The paper also offers a design guideline for the qualification of fiber-optic feed-throughs for horizontal and vertical trees and landing strings, and the fiber and system performance criteria for optical fiber sensors of various types. It will review the measurement capabilities and system requirements of various fiber sensor systems and will present the design problems, qualification methodology and test results for the development of fiber-optic feed-though systems for both vertical and horizontal X-trees.

With the economics of deepwater production driving subsea technology development, the ability to extend tieback distances is critical to the continued effort to reduce CAPEX for deepwater projects. In "mature" regions such as the GOM shelf and the UK North Sea, the tie in of remote satellite developments is already extending the life of existing platforms beyond their original decommissioning dates, yet there are many potential developments just out of reach of current tieback technology. At the leading edge of subsea production development, some operators are investigating tieback to shore with target distances of 200 km or more. Fundamental programs in Subsea Separation, Multiphase Pumping and Subsea Electrical Power Transmission are demonstrating the critical need for high power and for high bandwidth, error free communication, where subsea processing and long step-out distances are necessary. These programs have identified wet-mateable high-voltage, power connectors and fiber-optic communication and, consequently, wet-mateable fiber-optic connectors, as critical technologies enabling the installation and hook up of the core modules for each project. With many of these programs having reached the stage of subsea trials, or in some cases, full production installations, the wet-mate connection systems have been subjected to comprehensive "real life" production programs. The performance of these connectors, the benefits of high-voltage power systems and fiber-optic communication and the lessons learned, can significantly improve the application of these system critical technologies in future subsea production and extended tieback systems. Introduction The key to the use of new technologies is to start with the end in mind. It's hard to justify using more expensive systems on a straight replacement basis alone. Operators have to look at the project's total system cost over the life of field. For most subsea installation scenarios, the economics of subsea production can be improved by making use of leading edge technologies that focus on advanced facilities construction, production control and flow assurance. These technology developments are not only critical to the improved economic development of deepwater (>500m) prospects where much of today's industry focus lies, but also for technical success in ultra deep waters as we pass 2000m. They are also relevant for extending the life of facilities and infrastructure in the shallow water, mature regions like the GOM shelf and the UKCS. The implementation of new technology will only move forward if accompanied by suitable and in-depth risk assessment and risk management. Although the implementation of new technology will always carry an associated risk, the level of risk can be reduced and kept within acceptable limits through proven engineering and management practices and the application of well directed system-wide qualification test programs and detailed production trials. This approach to the implementation of new technology has been successfully proven on a number of recent high-profile developments. The following sections will look at a variety of technologies critical to the ongoing development of the subsea oil industry and which are dependant on the use of wet-mate high-power and/or optical connectors.

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One of the most important areas of Offshore Oil and Gas R&D in recent years has been the ongoing development of improved reservoir and production monitoring technology. Nothing else offers the potential returns that come with increased understanding of the reservoir and the improvements in realtime production control that this knowledge can provide. As reported at OTC 2003, Ocean Design, Inc. (ODI) has been developing products for this application for the last four (4) years, working with the Intelligent Wells Group at BP America Production Company in Houston. 2003 has seen the completion of development and qualification of a revolutionary small form-factor, wet-mateable, fiber-optic connector designed for subsea x-tree and down-hole applications. From initial conception, this has been a challenging development, given the harsh environments encountered down-hole and at the tree-tubing hanger interface, and the small space envelope available through any vertical or horizontal x-tree system. Ocean Design is working closely with BP and FMC on a first system to mount to the FMC horizontal tree specified by BP for the Atlantis Project in the deepwater GOM. Ocean Design has also been modifying the Atlantis design to be used with a vertical x-tree system for BP's Greater Plutino Project in Block 18 offshore Angola. Following on from last year's paper (OTC 15323) that discussed the potential applications and development of the ICONN connection system, this paper focuses on the lessons learned during the development process, discusses the qualification program in greater detail and presents the results obtained. Introduction Over the last twelve months, an increased focus has been directed at the potential of optical fiber in the Offshore Oil & Gas Industry. Optical fiber offers one method of achieving intelligent well sensor technology and is being considered for installation on a few major, key projects over the next two (2) years. Intelligent well monitoring and the near future step to intelligent well control have the potential to significantly improve the economics of deepwater wells through a combination of risk mitigation(Ref 1) through optimized well operation and maintenance, and increased hydrocarbon recovery. Not only does this improvement in reservoir performance mean that the economics of new fields can be improved by a significant margin, it also has two (2) other benefits.Review of marginal fields will identify fields that can now be economically developed.Producing fields may have the identified recoverable reserves increased, and some fields that had already reached the point at which economic recovery of additional reserves was not previously justified, may be extended and possibly even some shutdown fields reactivated. Optical fiber sensors can provide high-quality data on down-hole conditions (continuously and in real-time) and are inherently compatible with the down-hole environment. Optical fiber provides a range of sensor technologies including Distributed Temperature Sensing (DTS), in-fiber point source sensors (typically of the Bragg grating type) and passive mechanical point source sensors that are read optically through an attached optical fiber.

The trend to reduce topside facilities and the frequent use of subsea completions over extended step-out distances has increased the volume and complexity of subsea date communications beyond the capacity of conventional systems. Improved reservoir management using intelligent sensors, metering and process equipment, requiring real time monitoring and control, dictates the use of widebandcommunication. Fibre optics offers the necessary volume of data transmission, with the high noise immunity needed for data integrity and safety, for the severe EMI environments created where motors and power cables are used. The system uses conventional optical fibre conductors with 1550 nm laser generated optical pulses as the information carrier. Data rates of 2.0 Mbs−1 are achievable, unrepeated, over distances in excess of 100 Km, with extremely low error rates. Equipment and installation costs will be comparable with current hard-wired technology, demonstrating that single mode optical communication is a technically and commercially feasible, and reliable, alternative to existing electrical systems. Introduction The high cost and hazardous nature of recovering hydrocarbons offshore, have led to the trend to reduce topsides facilities, and to the growth in subsea production control. Subsea control capabilities have been considerably enhanced by the recent generation of microprocessor based systems. The latest control facilities enable the provision of a subsea interface for advancedtechnology installations, These include artificial reservoir lift systems, multiphase flow measurement, down hole monitoring and intelligent sensors, as well as the conventional tree control functions. However theseadvanced technologies impose increased data processing and communication overheads in the form of closed loop motor control, local data processing multi channel communications, downloading of calibration software, and intelligent diagnostics. This expanded functionality has created a need for increased data transfer. In particular the controls umbilical must now provide a data highway capable of supporting communications between topsides control systems and a network of Subsea Control Modules (SCM's), and their extended control functions. Traditionally this has been implemented using either a twisted pair or coaxial conductor, or by utilising the power conductors(power and signal combined). The available data transmission rates have been necessarily low, often of the order of a few hundred bits to reduce errors, maintain reliability and provide an economical solution. This transmission performance is no longer sufficient for the inevitable requirements of the offshore industry, A high bandwidth communication link is now a critical enabling technology for the future of subsea control. The move towards placing high power electrical equipment subsea, has created a need for a communications system with greater immunity to Electro Magnetic Interference (EMI). The maximum impact of power transmission on a subsea communication system will be encountered where subsea produced fluid boost facilities such as electrically powered multiphase pumps are used. These high power, variable frequency motor drives, generate unacceptably high levels of EMI for conventional screened data conductors, Optical fibres offering inherently high noise immunity and improved attenuation characteristics over conventional conductors are suitable for such applications.