An introduction, types, sensing, monitoring and testing of offshore structures.

1. OFFSHORE STRUCTURE

2. OUTLINE
INTRODUCTION
TYPES OF STRUCTURES
SENSING AND MONITORING SYSTEM
ENVIRONMENTAL FORCES
SENSORS
NON DESTRUCTIVE TESTING
MODERN SYSTEM
RECOMMENDATIONS

3. INTRODUCTION
Installation of structures and facilities in a marine environment
Production and transmission of electricity, oil, gas and other
resources.

4. TYPES OF STRUCTURES

5. SENSING AND MONITORING SYSTEM
 Highly accurate and reliable system for productivity and safety.
 Sensing technologies that can withstand the most extreme
conditions to deliver vital information in real time
 Advanced monitoring systems can identify and even facilitate
rapid response to events that could otherwise lead to leaks,
downtime, and even catastrophic failures.
 Improve environmental security and safety in deepwater
operations, reducing risk of spillage and other hazards.

6. ENVIRONMENTAL FORCES ON
OFFSHORE STRUCTURES
Different types of load
(e.g. permanent, operating, installation, accidental)
Environmental forces
(e.g. wind, wave, earthquake)

7. SENSING TECHNOLOGIES
Measurement to mitigate structural failure
(e.g. strain, vibration, shock)
Flow Assurance – problem identifications
(e.g. temperature, pressure, hydrate formation)
Leak Detection
(Subsea field inspection)

8. VIBRATION
To prevent health hazard (ENDEVCO 5241)
Monitoring of offshore structure (PCB 352C33/INTEGRIpod/TE)
Monitoring in subsea and surrounding (ABBWimon100/MSR /Shocklog Dataloggers)

9. SELECTION
Frequency range
Amplitude range
Sensitivity
Detection Type
Input/output Type
Environmental/Physical factor

10. SENSORS

11. SENSORS

12. STRAIN
The strain of a body is always caused by an external influence or
an internal effect.
Strain might be caused by forces, pressures, moments, heat,
structural changes of the material.
A Strain gauge is a sensor whose resistance varies with applied
force.

13. SELECTION
Range
Thickness
Connection
Environmental Factor

14. SENSORS

15. SHOCK
A mechanical or physical shock is a sudden accelerationcaused
by impact, drop, explosion etc

16. SELECTION
Sensitivity
Measurement Range
Frequency Range
Electrical/Environmental/Physical Characteristic

17. SENSORS

18. SENSORS

19. ACOUSTIC
Subsea Acoustic Detectors/Sensors are intelligent devices that
detect and monitor the acoustic noise generated by oil, gas or
multiphase pipeline flows and due to the other operational
equipments.
These detectors give operators greater knowledge of what is
happening in their pipelines which leads to increased pipeline
integrity and cost savings.

20. SUBSEA ACOUSTIC DETECTOR

21. ACOUSTIC MEASUREMENT

22. CONTACTLESS MEASUREMENT SYSTEM

23. FLOW METER

24. TEMPERATURE AND PRESSURE SENSORS
One of the ways to optimize oil and gas production is to get better
subsurface and surface pressure and temperature measurements to
improve many aspects from artificial lift optimization to real-time
reservoir and topside production monitoring.
These pressure and temperature sensors are designed for extreme
and corrosive applications such as downhole well bores, deepwater,
deserts etc.

26. SENSOR ANDGUAGE

27. SENSORS ANDDATALOGGER

28. SELECTION
Operating pressure
Temperature and Pressure range
Material of construction
Connection type
Accuracy

29. EROSION
Subsea Sand Erosion Sensors measure metal loss caused by the
impact of sand particles flowing in the production line.

30. CORROSION
Corrosion Monitoring Sensors measure pipe corrosion with high
accuracy and rapid response.
The sensors track corrosion rates as an increase in electrical
resistance of the element as it is exposed to in-line corrosion.
Early corrosion warnings enable the operator to implement
corrosion mitigation programs for improved pipeline integrity.

31. SUBSEA CORROSION MONITORING
SENSORS

32. SAND MONITORS
Subsea Sand Monitors are intelligent devices that provide an
immediate response to the onset of sand production.
The monitors utilize the acoustic noise produced by sand particles
to calculate real-time sand production in oil, gas or multiphase
pipeline flows.
Such information leads to improving the integrity of operator assets
and optimizing oil & gas production.

33. SAND MONITORS

34. SELECTION
Operating Pressure
Operating Temperature
Measuring Range
Sensitivity
Water Depth

35. DOWNHOLE WIRELESS SYSTEMS
Downhole Wireless Systems continuously monitor temperature and
pressure for the subsea well's .
Comprised of a wireless reader, a wireless PT Transponder and
antennae.
The advanced system improves production and offshore safety,
providing early high–pressures warnings, protecting casing
integrity and preventing pressure build–up.

36. DOWNHOLE WIRELESS SYSTEMS

37. SELECTION
Temperature Operating Range
Pressure Operating Range
Communication Type
Communication protocol

38. HYDRATE FORMATION ANDDETECTION
Gas hydrates can block pipelines, interrupt production, and in
worst case even cause bursting flow lines.
Multimodal Flow Assurance Metering Station

39. LEAK DETECTION

40. LEAK DETECTION
Leak detection system utilizing four ultra-sensitive acoustic sensors
which constantly monitor wide areas for ultrasound generated from
the release of pressurized gas/liquid.

41. LEAK DETECTION

42. GAS ANALYZER/SENSOR

43. LEVEL
TRANSMETTER/ANALYZER/SENSOR
pumpOverfill prevention, high and low level alarms, and
protection.

44. VISCOSITY METER/SENSOR
Viscosity Meter is a fast-response sensor that delivers reliable
viscosity temperature measurement in pipelines, bypass loops and
tanks.

45. DENSITY METER/SENSOR
Density Meter provide continuous, real-time density and
concentration measurement in pipelines, bypass loops and
tanks.

46. LIQUID TRANSMITTERS ANDSENSORS
Provide the most complete range of continuous on-line
measurement for pH, conductivity, dissolved oxygen etc

47. FLAME DETECTORS

48. AIR PARTICLE MONITOR
Infrared optical monitor that is
hazardous areas for constant, reliable monitoring
certified for use in
of
ambient air for products of combustion such as smoke, oil
mist, carbon, dust, and ash.

49. NON DESTRUCTIVE TESTING
Technology Capabilities Limitations
Thermal imaging method
•Impedance tomography
•Thermography (infrared cameras)
Fast
Cost effective.
Trials using drones are currently being conducted,
which will detect cracks up to 0.3 mm
Limited implementation in offshore structures.
Camera resolution for detecting cracks
Laborious Image processing
Cracks detection needs more automation from
footage.
Ultrasonic methods
•Piezoelectric transducers
The depth of penetration for flaw detection or
measurement is superior to other NDT methods.
It is sensitive to both surface and subsurface
discontinuities.
It is highly accurate in determining reflector position
and estimating size and shape.
Difficulty of inspection of rough, irregular, very
small, exceptionally thin or not homogeneous
materials.
Coupling medium to promote the transfer of sound
energy into the test specimen is required.
Fatigue and modal propertiesmonitoring
•Accelerometers
•MEMS
• Plastic optical-fiber based accelerometers
•Velocimeters
High reliability, mature technology
Easy installation
Stable performance
High number of uncertainties when applied in the
offshore environment.
Difficulties in wind and wave loads measuring.
Radiography
•Det Norske Veritas
Detect metal thickness variations Depth of penetration
Magnetic Particle Inspection
•EMI Instruments
•Jaker Instruments
Use magnetic phenomenon of flux leakage to detect
cracks and surface discontinuities in ferrous material
Expensive

50. MODERN SYSTEM EXAMPLE
TRIDENT SENSING AND INSPECTION SYSTEM
Deepest monitoringsystem – 7500 ft
Longest monitoring system– 60miles
Coldest – cryogenic LNG andLN2
Hot – interior of solid rocketmotor

51. MONITORING FROM REMOTE
LOCATIONS
Remote display of real-timedata
Secure & encrypted datatransmission
Getting the right data to the make the rightdecisions

52. TRIDENT SYSTEM

53. TRIDENT SYSTEM

54. TRIDENT SYSTEM

55. RECOMMENDATIONS
System Description Maturity Key dataUtility Weaknesses
Continuous Monitoring
Active acoustic Acoustic radar which
“looks” for theacoustic
reflection which a leak
will/can generate
Detection of oil under
water. Area coverage.
More sensitive to
detection of gas leaks
Sensor needs a lot of
electric power and a
large
bandwidth. Sensitive to
nearby
(shadow
equipment
effect).
Generates large
volumes of data
Supplied commercially
for inspection,
prototype for subsea
monitoring
Resolution better than
10°/1m, ranges depend
on the system
Fibreoptics Fibreoptic cable laid
along a pipeline to
measure changes as a
result of a leak, by
measuring either
temperature changes or
contact (soundwaves)
Area coverage. Can
locate a leak along a
pipeline
Primarily for pipelinesat
present
Delivered
commercially for
pipelines, conceptual
version for subsea
facilities
Detectstemperature
pressure,changes,
vibrations/
loads(µm)
Fluorescence Uses a light source
with a certain
wavelength toexcite
molecules in the
measured object toa
higher energylevel
Point sensor, possibly
with a sight line of 3-
5m.
Sensitive
fouling
to marine In use together with
ROV, delivered
commerciallyfor
pipelines, conceptual
version for subsea
High sensitivity (ppm),
high specific
classification abilityfor
hydrocarbons, range:
> 100m in air, 1-10m
under water

56. RECOMMENDATIONS
System Description Maturity Key dataUtility Weaknesses
Continuous Monitoring
Capacitance Measures thedielectric
constant
surroundings
significant
between oiland
seawater)
to the around
(very subsea
difference valves,
templates,
isolation
manifolds,
etc gas/natural leaks from
give
the seabed can
accumulate and
false alarms
Point sensorfor use Requires a collector. Delivered
Ocean currents may lead commercially,
the leak away from the alarms have
false
been
sensor, shallow reported
Detection of
hydrocarbons at 10-
50% filled probevolume
Biosensors Instrumented biological
organisms (such
mussels)
Point sensorsuitable
waterdepth
down to 500 metres of from the sensor (deep water,
100-500metres)
Ocean currents may lead Pilot (shallowwater, < High specific
as for leak detection the hydrocarbons away 100m), conceptual phase sensitivity
Methane sniffer Diffusion ofmethane
(dissolved in water)
chamber
and into the detection methane
Point sensor able to Recalibration
detect all types of after one
through the membrane hydrocarbons containingoperation,
after two.
and
required
Sensitiveto
marinefouling
year of long-
term stability not
maintenance demonstrated
necessary Delivered commercially, Depends on supplier

57. RECOMMENDATIONS
System Description Utility Weaknesses Maturity Key data
Continuous Monitoring
Optical camera Video camera for subsea
monitoring
Photographing
makes it possibleto
lea
k
Camera image can be
made available in the
A number of systems in
operation for upto
Area +/- 45° in
directions withfixed
all
classify control room, but no three
years
.
lighting. Distance to
automated detection. Supplementary object: 1-10m
Particles and pollution in monitoring with the aid
the water can makethe of video analysisis
visibility of the object being developed
difficult. Problems with
overtrawlability and
maintenance
Laser opticalsystems Use of rangegated Provides 3D image Optical systemsrequire Experimental systems Can image volume
vision/ and continuous
or
cleaning
an
d
being tested within a range of10-
light detection an
d
intermittent
operation
,
maintenance 50m
ranging (Lidar)and functions in
limited
laser radar(Ladar) visibility
Passive acoustics Hydrophones pick
up
Area coverage,
can
Unsuitable for leaks with Qualified to ISO Range limited
by
irregularities in the light detect subsea leaks, can a differential
pressure
13628-6, Statoil pressure differential
picture around the also be usedfor close to 0 bar. Influenced TR1233. Almost
100
between leakand
sensor condition monitoring of by systems delivered. surroundings

58. RECOMMENDATIONS
System Description Maturity Key dataUtility Weaknesses
Continuous Monitoring
Mass balance
simulation model
with Real-time
simulations
measurementdata
from instrumentation stream.
distributed across the instrumentscan
production system usually be
feasibility studymust
be conducted
the production has little effectwhen
Existing production isstarting/
stopping, etc. Calls for
used, simulations, and will be
less
effective when
production/pressure falls
flow Alarm if the simulation Reduced accuracy with Mature technology
based on indicates loss of mass in unstable production, and
Depending on
installation, up to ~5%
accuracy
sensors in the
production/
control system
data
from
Pressure/ temperature Checking measurement Big leaks
distributed across the register. production isstarting/
production system
could be
Considerably
sensitive than
balancewith
simulation
can have Reduced accuracy with Sensors
effects which an unstable production, and included inthe
instrumentation operator can potentially has little effect when production facility,
a gradually growing leak than leak
difficult. detection
less
mass
are normally Assumes that pressure
downstream
but from the choke valve is
are intended for significantly higher
stopping, etc. Picking up production control rather than the ambient
pressure

59. RECOMMENDATIONS
System Description Utility Weaknesses Maturity Key data
Periodic monitoring
Internal inspection of
pipelines
Suitable for risers and
pipelines
Periodic
inspection by ROV
/AUV (both pipelines
and subseafacilities)
Checking allvisible
equipment
Weaknesses depend onthe
sensor type used.Some
will require clear visibility. A
number of sensor types
will generate large
amounts of data
which must beanalyzed
Mature
technology
Periodic inspection by
AUV (primarily
pipelines
External inspection
of
equipment
Weaknesses depend on the sensor
type used. Some
will require clear visibility. A
number of sensor types
will generate large
amounts of data which must be
analysed
Periodic testing
(function and barrier)
of
Xmas-tree valves
Checking Xmas
trees
and manifolds
Mature
technology

60. THANK YOU