ECHOES Sub-Bottom Profilers ECHOES technology and performances, DELPH Seismic software integration of seismic and SBP data.

1. ECHOES
General Presentation
iXBlue Day, Hamburg, 29/03/2011

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ECHOES product Line
Sub-Bottom Profiling is a mean to acoustically form vertical images of the sub-soil.
It traditionally differs from reflection seismic in the way that:
Higher frequencies are used to obtain thinner vertical resolution
Pulse modulation – chirp – is used to bring an additional gain to data
While using chirp pulse modulation to obtain optimal data quality, IXSEA employs
particular transducer types to reach lower frequencies and thus deeper
penetration.
IXSEA has an extensive experience in developing high-quality sub-bottom profilers,
they are now available in a complete product family: ECHOES.

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The great dilemma : Resolution versus Penetration
 Selectinga sub-bottom profiler is a trade-off between higher resolution and deeper
penetration. Still, it is possible to balance between those using different sensors
and software technologies
10kHZ 5kHZ

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ECHOES Range
ECHOES is a range of wide-band chirp Sub-Bottom Profilers
From very-low frequency and deep penetration model to very high resolution systems.
Special acoustic designs provide lower frequencies than conventional chirp SBPs
The transducer quality results in flat-spectrum output (within 3dB) over the entire
bandwidth, thus allowing fully tuneable pulse models and optimal efficiency.

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Transducer Design – Tonpilz Transducer
 Tonpilz Transducer:
 Stack of ceramic rings
 Heavy tail mass
ECHOES 3500 ECHOES 10000
 Light radiating head mass
 The ceramic rings are compressed between the tail and head

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Transducer Design - Janus Helmholtz
 Janus Helmholtz:
 Two Tonpilz transducers mounted back to back.
 Cylindrical housing creates Helmholtz cavity. ECHOES 1500 ECHOES 5000
 Helmholtz resonance caused by fluid inertia.
 Helmotz resonance extends the operating frequency of the transducer at the low
end of the spectrum, while having a compact design.
Typical Signal Level response of a transducer.

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Chirp technology
• Correlation process – Matched Filtering - improves the signal to noise ratio
• Additional gain, referred as processing gain, is defined as:
PG = 10 log (B * T)
where :
• B = bandwidth of the pulse
• T = pulse length
Examples:
a) Pulse definition
• ECHOES 1500: B = 2850 Hz T=100ms PG=24dB
• ECHOES 5000: B = 5500 Hz T=50ms PG=24dB
b) Measured Emitted Acoustic power:
• ECHOES 1500: 201dB re 1 μPa at 1m
• ECHOES 5000: 203dB re 1 μPa at 1m
c) Results
• ECHOES 1500 has an apparent acoustic power of 225dB
• ECHOES 5000 has an apparent acoustic power of 227dB

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Resolution of conventional systems
 Fora monochromatic Sub-Bottom Profiler system such as a boomer or a sparker,
the resolution may be calculated by:
R=C*L
Where:
 R = Resolution (m)
 C = sound speed (1470 m/s)
 L = Pulse Length (s)
 Typical boomer:
 At low energy, 120 µs pulse
 Resolution = 17 cm
 More often resolution in the range of 25 cm.
 The longer the pulse, the worst the resolution

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Resolution of Chirp systems
 Resolution is function of the sweep bandwidth
R=C/2*B
Where
• B= bandwidth of the pulse (Hz)
• C= Sound speed (1470 m/s)

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Improve the resolution: Enlarge the bandwidth ...
 OneJanus-Helmholtz transducer has 3 kHz bandwidth around 3000 Hz.
 Mounting three tuned transducer increase the bandwidth up to 8000 Hz

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Improve the penetration: Increase the power ...
 Boomer
 200J= 212dB
 26cm resolution.
 Increasingthe Power of a boomer
adversely impacts resolution.
 ECHOES 1500
 223dB
 27cm resolution
 ECHOES 5000
 227dB
 13 cm resolution
 Increasing ECHOES power has no
effect on resolution.

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Improve the quality: Choose the best deployment
 Hull/Pole Mount
 Advantages
 Fixed installation
 Motion compensation
 Multi-Ping
 Limitation factors:
 Sea State
 Water-depth
 Surface Tow
 Advantages
 Easy deployment
 No sea surface reflection
 Disadvantages
 Motion
 Vessel Noise
 “Deep Tow”
 Advantages
 No Vessel Noise
 Reduced Motion
 Disadvantages
 Winch and Cable
 Sea Surface Reflections

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DELPH Seismic Acquisition Software
A New Philosophy
ONLINE  Acquisition systems are generally under utilised.
 Only need basic signal processing to monitor the
Acquisition quality of the gathered data.
 Extreme processing during acquisition can hide poor
quality data, that may only come to light when it is too
Storage late to do anything about it.
 Acquisition systems must be reliable.
QC  The more features a software product has the larger
the code base needs to be and inevitably there is
more potential for bugs. Bugs are really bad in
acquisition. Vessel time is expensive!
OFFLINE
Keep the acquisition simple.
Processing
 Keeping the acquisition simple involves a separate
package dedicated to processing and interpretation.
Interpretation
It no more needs a scrolling waterfall display …

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DELPH Seismic Processing & Interpretation Software
ONLINE
XTF
or
Acquisition SEGY
Storage
QC
OFFLINE
Processing XTF
or
SEGY
Interpretation

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DELPH Seismic Acquisition Software

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DELPH Seismic Processing & Interpretation Software
 Whole line approach for processing
 Processing is no more linked to data replay.
 Escape from the Change-Replay- Change-Replay- Change-Replay- cycle …
 Processing changes can be done on the displayed area or the whole line without
scrolling
 Whole line approach for interpretation
 Zoom from sample resolution to large geological features on-screen
 Speed-Corrected and Geo-Referenced profile to perform thickness, slope measurements
 Direct access to geo-referenced data at any scale
The processing and interpretation software
is no more based on an acquisition package

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DELPH Seismic Processing & Interpretation Software

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ECHOES 1500 Data processed in DELPH Seismic Interpretation
55ms
145ms
3km

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ECHOES 1500 Data processed in DELPH Seismic Interpretation
55ms
145ms
3km

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ECHOES 3500 Data processed in DELPH Seismic Interpretation
325ms
640ms
14km

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ECHOES 3500 Data processed in DELPH Seismic Interpretation
1865ms
2165ms
15.5km

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ECHOES 3500 Data processed in DELPH Seismic Interpretation
605ms
870ms
5km

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ECHOES 5000 Data processed in DELPH Seismic Interpretation
5ms
50ms
2km

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ECHOES 10000 Data processed in DELPH Seismic Interpretation
0ms
25ms
2km

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Evolution
 IXSEA masters a broad range of subsea technologies:
 Inertial navigation and motion sensing
 Acoustic positioning
 Acoustic imaging systems (sonars, sub-bottom profilers)
 Software
 To higher data quality in standard products or fully integrated system.
ECHOES 1500 ECHOES 3500 ECHOES 5000

26. Questions ?
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