Present and Future Possibilities Within Optical Condition Monitoring of Flexible Risers

Weppenaar, Nick; Kristiansen, Mikael

doi:10.4043/19427-ms

Cited by 5 publications

(6 citation statements)

References 2 publications

(2 reference statements)

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“…Due to the demands for EX proofing, transmission lengths and operational robustness, fiberoptical sensing methods are an ideal way of monitoring flexible risers, as explained in more detail by [Weppenaar and Kristiansen, 2008]. However, while the methods of Fiber Bragg Gratings and Brillouin Scattering are relatively easy to adapt for use in the annulus environment, no optical gas sensing method has been feasible for use in flexible pipes due to a number of problems, such as insufficient sensitivity and large optics.…”

Section: Existing Gas Sensing Methodsmentioning

confidence: 99%

“…Internal and external monitoring of pipe strain and temperature are on their way to becoming established technologies (Weppenaar and Kristiansen 2008) with all the operational safety and lifetime extension these technologies enable. However, the field of annulus gas monitoring has so far been lagging, in that no accurate sensing technology which is continuous, accurate and free of electrical leads has existed.…”

Section: Introductionmentioning

confidence: 99%

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SS: Advances in Flexible Riser Technology: Fiberoptic Gas Monitoring Of Flexible Risers

et al. 2009

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This paper presents a new advancement within the field of optical gas measurement with applications to the monitoring of gases inside the annulus of flexible risers used in the offshore industry. This advancement is based on the novel Quartz-Enhanced Photoacoustic Spectroscopy (QEPAS) technology. Specifically, we report on the first demonstation of such a gas sensor system using a spectraphone (a module for detecting laser-induced sound) consisting of a quartz tuning fork (QTF)/microresonator assembly and two commercial single frequency diode lasers operating at λ =1.58 μm for detecting H 2 S as well as CO 2 and at 1.65 μm for detecting CH 4 . A minimum detectable H 2 S concentration of 10 ppmv (parts per million by volume) at the 1σ level was obtained for t=1 s averaging time, scaling down as 1/t ½ up to 1000 s (verified) This implies that a 100 s sampling time will result in a minimum detectable concentration of 1 ppm. For CO 2 and CH 4 , the minimum detectable concentrations were 270 and 1.5 ppm, respectively. The measurement technique will be described and test results will be presented along with implications for the field of riser condition monitoring.This system will allow continuous monitoring of the annulus chemical environment in flexible risers. Current gas monitoring solutions are either offline with a low sampling frequency or require cumbersome EX protection near the pipe (gas chromatography). By contrast, the proposed technique will allow a compact sensing unit connected only with fiberoptics that can monitor annulus gas levels continuously and with high accuracy.Laboratory test results show a high level of measurement accuracy even over short timescales. These results show a clear advantage over conventional systems due to the real-time sampling, and the compact final design being free of electrical leads allows for a compact bolt-on solution which can be installed almost anywhere without compromising working space. This also minimises the number of work-hours necessary near the pipe to maintain the monitoring system. Wells may change fluid composition in a way which brings the problem of corrosion fatigue to a riser never intended for these conditions. For example, wells which initially were sweet may become sour over time. Having a gas monitoring solution in place will allow for real-time risk assessment as well as a warning system for changes in riser annulus conditions. For sour service pipes, a gas monitoring solution will allow up-to-date and highly precise corrosion fatigue calculations. Combining the input from gas monitoring with the data from other sources, such as strain and temperature monitoring, will give unprecedented insight into the field service conditions of a riser, yielding a far greater level of operating safety than previously feasible.

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Section: Existing Gas Sensing Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

SS: Advances in Flexible Riser Technology: Fiberoptic Gas Monitoring Of Flexible Risers

et al. 2009

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“…Different monitoring sensors and monitoring techniques are used on composite structures and optical fibre materials [47][48][49][50]. One such technique is the Rayleigh backscatter via its Optical Backscatter Reflectometer (OBR) and the use of a distributed fibre optic network to identify accidental impact damage early [51][52][53][54][55][56]. This method delivers high spatial resolution strain and temperature measurements from several sensors placed all along the optical cable.…”

Section: Introductionmentioning

confidence: 99%

Guidelines on Composite Flexible Risers: Monitoring Techniques and Design Approaches

et al. 2022

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The increasing energy demand has led to more explorations in the oil and gas industry. To achieve this, marine risers and pipelines are used to convey fluid and other resources to meet the increasing demand. In recent years, hybrid flexible composite risers have become more adaptable. Flexible risers have already proven to be a popular riser solution for various floating production systems in shallow to deepwater in many parts of the world due to their good dynamic behaviour and dependability. The hybrid flexible composite riser is made up of numerous layers of plastics, flexible pipes, composites, and steel. Some innovative monitoring methods, such as Fiber Optics Bragg Gratings (FBG), are based on a clamped composite structure with embedded optical fibre. This study presents characteristics of the monitoring techniques of composite flexible riser technology. The advantages of the monitoring techniques include aiding composite riser measurements, recording data from riser deformation, improving integrity assurance, and dependability of design from stable readings. It also proposes some design approaches as guidelines that are advised, with some policy implications.

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“…Marinho et al [7] have described the use of superficial monitoring techniques for continuous flexible riser integrity assessment, reporting field trials involving percolated gas monitoring, nitrogen injection in the annular space, deformation monitoring, and visual inspection with a video camera. Even though all these methods have been yielding encouraging results, it is the technique based on optical fiber sensors that is closer to reach a mature status [12][13][14][15][16][17][18]. Non-invasive magnetic inspection is also undergoing a series of laboratory experiments and is now ready to be tested in the field [11].…”

Section: Introductionmentioning

confidence: 99%

“…Morikawa et al [15] presented results of laboratory and field tests where a thin steel collar instrumented with fiber optic strain sensors was clamped to the riser outer surface measuring circumferential strains and therefore changes in its diameter. This method has been reviewed recently by Weppenaar and Kristiansen [17]. The second approach, which in contrast with these two methods offers direct measurement of strains in the wires, was first reported by Andersen et al [13] in 2001, who successfully inserted optical fibers containing multiple strain sensors in the wires of the armor layers of flexible risers.…”

Section: Introductionmentioning

confidence: 99%

Real time continuous structural integrity monitoring of flexible risers with optical fiber sensors

Morikawa¹,

Camerini

Braga

et al. 2010

All Days

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Even though the armor layers play a major role in the structural integrity of flexible risers, operators and service providers worldwide are still in search of reliable inspection or monitoring techniques capable of detecting the presence of cracks or other defects in the metallic wires that compose the internal and external armor layers of the pipe. In the present contribution, we report the effort undertaken by Petrobras in order to face this challenge. Novel inspection and monitoring systems, based on acoustic emission, measurement of residual magnetic field, optical sensing, or employing visual monitoring cameras, are being developed and tested. Among these techniques, the one relying on optical fiber sensors has provided the best results so far. The use of fiber Bragg grating sensors for directly measuring strains in each wire of the external traction layer offers an accurate and reliable real-time, continuous monitoring technique, providing the operator with valuable information and early warning if any deviation from the expected wire's structural behavior is detected. The paper describes the technique and presents results from full scale laboratory tests as well as from the first field trial conducted in an offshore platform operated by Petrobras in Campos Basin.

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Present and Future Possibilities Within Optical Condition Monitoring of Flexible Risers

Cited by 5 publications

References 2 publications

SS: Advances in Flexible Riser Technology: Fiberoptic Gas Monitoring Of Flexible Risers

SS: Advances in Flexible Riser Technology: Fiberoptic Gas Monitoring Of Flexible Risers

Guidelines on Composite Flexible Risers: Monitoring Techniques and Design Approaches

Real time continuous structural integrity monitoring of flexible risers with optical fiber sensors

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