Development and Testing of a Friction-Based Post-Installable Fiber-Optic Monitoring System for Subsea Applications

Abstract

This paper presents the design and development of a friction-based coupling device for a fiber-optic monitoring system capable of measuring pressure, strain, and temperature that can be deployed on existing subsea structures. A summary is provided of the design concept, prototype development, prototype performance testing, and subsequent design refinements of the device. The results of laboratory testing of the first prototype performed at the National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) are also included. Limitations of the initial concept were identified during testing and future design improvements were proposed and later implemented. These new features enhance the coupling of the sensor device and improve the monitoring system measurement capabilities.A major challenge of a post-installed instrumentation monitoring system is to ensure adequate coupling between the instruments and the structure of interest for reliable measurements. Friction-based devices have the potential to overcome coupling limitations caused by marine growth and soil contamination on flowlines, risers, and other subsea structures. The work described in this paper investigates the design and test of a friction-based coupling device (herein referred to as a friction clamp) which is suitable for pipelines and structures that are suspended in the water column as well as for those that are resting on the seabed. The monitoring elements consist of fiberoptic sensors that are bonded to a stainless steel clamshell assembly with a high-friction surface coating. The friction clamp incorporates a single hinge design to facilitate installation of the clamp and dual rows of opposing fasteners to distribute the clamping force along the structure. The friction clamp can be modified to be installed by commercial divers in shallow depths or by remotely operated vehicles in deep-water applications. NASA-JSC was involved in the selection and testing of the friction coating, and in the design and testing of the prototype clamp device. Four-inch diameter and eight-inch diameter sub-scale friction clamp prototypes were built and tested to evaluate the strain measuring capabilities of the design under different loading scenarios. The testing revealed some limitations of the initial design concept, and subsequent refinements were explored to improve the measurement performance of the system.

Guidelines on Asset Management of Offshore Facilities for Monitoring, Sustainable Maintenance, and Safety Practices

“…It should demonstrate that all hazards have been identified and assessed and are under control by effective safety measures so that the exposure of personnel to the hazards has been minimized. However, there is the need for organizations to include key elements of asset management, and related ideals, such as health and safety [ 254 , 255 , 256 , 257 ], risk assessments [ 258 , 259 , 260 , 261 , 262 , 263 , 264 , 265 , 266 ], gap assessments [ 267 , 268 , 269 , 270 , 271 ], audit [ 272 , 273 , 274 ], life extension [ 275 , 276 , 277 , 278 , 279 , 280 , 281 , 282 , 283 , 284 , 285 ], asset integrity [ 39 , 286 , 287 , 288 , 289 , 290 , 291 , 292 , 293 , 294 ], Safety Critical Elements (SCE) [ 295 , 296 , 297 , 298 , 299 , 300 ], safety case [ 301 , 302 ,…”

New Flow Assurance System With High Speed Subsea Fiber Optic Monitoring of Pressure and Temperature

“…The Clear Gulf JIP relies on oil and gas industry experts as well as test facilities at NASA. While the sensors on this project were dry-installed, the post-installed clamp design and adhesion to the pipe is recently improved with fundamental research and testing conducted by NASA Johnson Space Center [13,14] for long-term service life verification. The new clamp design is shown in Figure 12 with several enhancements over the prior clamp design [4,5].…”