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© Omnisens 2014
Fiber Optic Monitoring
Subsea Flowlines
Dana DuToit
Omnisens S.A.
MTS Leak Detection Symposium
November 2014
© Omnisens 2014
Omnisens - Technology
Subsea Umbilicals (What we’ve learned)
Subsea Flow Lines (2 Case Studies)
Direct Electrical Heating (DEH)
Indirect Heating (PiP)
Pipeline Concept for SS Leak Detection
Agenda
© Omnisens 2014
Privately-owned Swiss company, established in 1999
Spin-off from Swiss Federal Institute of Technology in
Lausanne (EPFL)
Headquarters in Morges, Switzerland
Offices in USA and Brazil
Highly educated team
Worldwide customer base
Distributors/Integrators in:
South America
Middle East
Europe
3
Omnisens is a world leader in high performance fiber optic monitoring.
Our fiber-optic solutions help organizations protect critical resources and
avoid the escalating consequences of delayed incident detection
protecting people, places and reputations along the way.
Asia (Malaysia)
Russia
Africa
Corporate Overview
© Omnisens 2014
Broad Range Of Capabilities
4
Engineering and design
Project management
Procurement
Manufacturing
Systems integration and testing
Installation and commissioning
Offshore intervention
Service, support and training
Software design and licensing
Omnisens operates according to the following
industry standards:
ISO 9001
ISO 14001
OHSAS 18001
Omnisens is certified by Achilles
© Omnisens 2014
Industries served
© Omnisens 2014
Our Technology
Turning optical fibers into fully distributed sensors
One interrogator connected
...to one fiber to monitor
thousands of locations
Local temperature or
strain
6
© Omnisens 2014
The physics behind the
monitoring
Scattering processes
Laser, lo
Page 7
© Omnisens 2014
Scattering medium
8
Sensing Technology 1/2
Laser, lo
Scattering processes used
for sensing applications:
Rayleigh
Detects loss variations
(OTDR and Fault location)
Raman
Scattered magnitude is
temperature dependent
Brillouin
Scattered frequency is
temperature and strain
sensitive (leakage, ground
movement, deformation)
© Omnisens 2014
Time Domain
The activating signal is
a propagating pulse and
the position is given by
the time of flight.
Spatial resolution is given
by the pulse width.
Frequency Domain
The frequency shift is
computed by recording the
Brillouin spectrum at different
frequencies and extracting
the maximum peak location.
and
Time domain analysis
9
Sensing Technology 2/2
© Omnisens 2014
Summary of Brillouin Scattering Benefits
Frequency Modulated Measurement
Independent of changing optical loss
Maintenance of sensor size and performance over long range
Fundamental power formatting advantage in silica fibers
Large optical budget (>40dB)
Effective Monitoring range is now as far as 100Km
FM measurement technique compatible with Optical Amplifier technology
Effective monitoring range can be extended to > 300Km
10
© Omnisens 2014 11
Umbilical’s – Quick review
© Omnisens 2014 12
> 900,000 flex cycles Sensor performance confirmed
Umbilical : Sensor Design and Integration
Deployed system
© Omnisens 2014 13
Bending strain monitoring
Strain/Temp Sensing Cable
Instrumented power umbilical
Monitoring of
Bending, tension, torsion strain
Temperature
> 900,000 flex cycles
Sensor performance confirmed
© Omnisens 2014 14
Condition monitoring
Power Umbilical – Offshore
Australia
How would the umbilical respond
to the increased load imposed by
new pumps?
Successful temperature
measurement during operation,
despite:
Attenuation: 30 dB
high reflexing peak of 13 dB
Fiber optic rotary joint
© Omnisens 2014 15
Flowline – Monitoring Experience
Flowline bundles
Direct Electrical
Heating DEH
Electrically
Heated Pipe in
Pipe
© Omnisens 2014
The Challenge
to maintain temperature
above a critical threshold
during long shut down and
start-up periods.
Heated Pipe-in-Pipe (ETH-PiP)
© Omnisens 2014
The Solution
Fully Distributed Sensing:
provides the temperature of the
heated elements
helps optimise the heating with
respect to the targeted pipeline
temperature
Heated Pipe-in-Pipe (ETH-PiP)
© Omnisens 2014
Temperatures measured during first ETH-PiP
heating and cooling
18
Pipe elevation profile
Pipe temperature profiles
© Omnisens 2014
Some 5 installations with up to 44 km DEH subsea flowline
monitored, including with riser and feeder cable
Direct Electrical Heated Cable System
© Omnisens 2014
Temperature profile example from one project
20
© Omnisens 2014
Profiles during DEH cable energization
© Omnisens 2014
Experience Summary
Subsea Umbilical Riser and
Flowline (SURF) monitoring…
Flow assurance – temperature evolution and
alerts with location for flowlines, pipelines
Leak detection and location in flowlines,
umbilicals, risers.
Umbilical fatigue (strain) and condition
(temperature and strain) monitoring
Validation of design and operation models
Heating control for DEH and ETH-PiP flowline,
• Closed loop, real time feedback
• Overheat detection
• Heating performance
Damage warning thanks to fiber optic break
detection
… for subsea structure integrity.
22
© Omnisens 2014
Concepts for SS Leak Detection
Utilize a Pipe-in-Pipe approach
Infrastructure is available for deployment
In-situ conduits within the annulus Most linear sensors can be either pre-installed or blown-in.
Precision Leak Detection before Spill
23
© Omnisens 2014
Pipe In Pipe Subsea Leak Detection Concept
24
Via DTS techniques
Other technics/technologies possible
- DAS, VST, Electrical etc.
Linear Sensor
In Conduit
Outer Pipe
Inner Pipe
Annulus
Redundancy
© Omnisens 2014
Fiber Optic Monitoring
Subsea Flowlines
Dana DuToit
Omnisens S.A.
MTS Leak Detection Symposium
November 2014