This paper summarizes leak detection technologies available for use on subseapipelines and the potential role of fiber optic cable (FOC) integritymonitoring systems to improve leak detection capabilities. Available systemswhich monitor offshore pipelines for potential leaks based on internalflowrates and pressures are described along with their limitations for rapidlydetecting small leaks. Alternative pipeline leak detection technologies whichhave been used on some specialized subsea pipeline projects to supplement thecapabilities of these flow-based systems are also described along with theirlimitations. The potential for modern FOC distributed sensing technologies tofill the remaining leak detection capability gaps is then addressed.
There is increased interest in improving leak detection system capabilitiesthroughout the pipeline industry. However, the primary application of thispaper is for offshore pipeline projects which may not be adequately covered byconventional flow-based leak detection systems and supplemental monitoring forpotential oil sheens visible on the sea surface. These applications includedeep water pipelines, where potential oil leaks may not reach the surface untilmiles away from the source, and subsea arctic pipelines, which could slowlylose significant oil volumes under the cover of winter sea ice. Other potentialapplications include subsea field developments and pipelines installed inunusually sensitive marine environments.
Distributed FOC sensor systems can monitor real-time temperature, acousticnoise/vibration and strain along many miles of pipeline. Changes in any one ofthese monitored parameters can indicate a leak event or other potentialintegrity threats to a pipeline. An overview of FOC systems already installedon offshore pipeline projects and the current testing status of FOC systems forpipeline leak detection are provided. Recommendations for installation andimplementation of the available FOC technologies for subsea pipeline leakdetection are summarized.
The limited applications of distributed fiber optic cable (FOC) monitoringsystems on subsea pipelines have not yet been used specifically for leakdetection purposes. The leak detection thresholds defined for FOC systems andthe procedures for design, installation and system repair will facilitate theuse of FOC systems to help ensure leak free pipeline operations.
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This paper addresses the latest developments in remote field control strategy and focuses on long distance umbilical control versus the use of a control buoy located over the field. The paper provides an insight into both the technology and also the commercial key drivers for the selection of control strategy.
The historical development of umbilicals and control buoys is summarised. The relevant technologies are described, covering aspects such as buoy design, telecommunication options, onboard power, fluid storage and injection capabilities, operational issues including access and maintenance, and opportunities for workover activities. The discussion is supported by case examples drawn from a number of fields around Australia.
The advent of huge, multinational offshore projects in the past decade and recent challenges in the timely, within-budget delivery of these projects finds the oil and gas industry grappling with how to bring balance to the planning and execution of these developments in terms of effective contracting, coordination, risk allocation, and conflict resolution. Many in the industry have determined that more effective interface management (IM)--meaning the proactive avoidance or mitigation of any project issues, including design conflicts, installation clashes, new technology application, regulatory challenges, and contract claims--would enhance the successful delivery of megaprojects. But this "discovery" of IM as a possible solution has been born from the disappointment of projects "gone wrong." That is, IM is not necessarily a new invention, but rather a critical project component that to date has not been fully appreciated or appropriately addressed. In truth, the management of interfaces--referring to common boundaries between people, systems, equipment, or concepts--has been a silent, hidden aspect of project management for a long time, but it was not specifically named or grasped until the rise of megaprojects, many of which have suffered significant losses.
Pinna, Rodney (School of Oil & Gas Engineering, The University of Western Australia) | Cole, Geoff (School of Oil & Gas Engineering, The University of Western Australia) | Murphy, David (School of Oil & Gas Engineering, The University of Western Australia) | McKay, Stuart (INTEC Engineering)
The Canyon Express field in deepwater Gulf of Mexico is a development consisting of multiple subsea gas-condensate wells owned by different companies. Each deepwater well (ranging from 6400 to 7250 foot water depth) flows into one of two 57 mile, 12" flowlines which tie the subsea wells to a shallow water host platform on the Continental Shelf. The production from each well is predominantly methane gas but also consists of produced water and condensate. Due to the nature of the production and the combination of high pressures / low temperatures expected, the potential for hydrate formation is a serious concern to system operability. To adequately protect the system against hydrate formation and deposition, injection of hydrate inhibitor (methanol) at each subsea well from a common umbilical system is being employed. Although wet gas metering is being used at each well to measure gas and liquid rate, water content per well cannot be accurately predicted. Thus, a robust methanol injection strategy was required to effectively inhibit hydrate formation. This paper presents the design of the methanol injection system and development of the overall injection strategy. Examples from the early field life of the Canyon Express development will be presented which demonstrate the application of this injection strategy to the system operation.