Overview about Explosive and the Non-Explosive Energy Sources used In Marine Seismic acquisition.

1. Explosive and Non-Explosive Energy
Sources In Marine Acquisition
By: Ali M. Ismael El-Baklishy
Content:
 Introduction.
Explosive Energy Sources.
- Air Gun.
- Dynamite.
Non-Explosive Energy Sources.
- Water Gun.
- Boomer.
- Sparker.
- Chirp System.
Reference.

2. Introduction:
Seismic method become the major geophysical technique now
days and this is because the massive importance of this method
in oil and gas prospecting as they are main sources of Energy.
Behind using Seismic method on land (on shore) for oil and gas
detection seismic method is used also in marine (offshore) for
the same aspect.
But the methodology of the seismic method onshore already
differs from that offshore. This difference in the Configuration
we use, the Energy source, the Receivers and in the all tools we
use.
In this paper we will discuss the Energy Sources in the Marine
Seismic prospecting.
https://www.youtube.com/watch?v=oFGNN4YFoH0

3. Explosive sources
It is the sources in which we use explosive material or using
explosion techniques to generate seismic energy in the sea.
These sources are 1- Airgun
2- Dynamite.
1-Airgun.
An airgun is used to inject a bubble of highly compressed
air into the surrounding water and is the most commonly
used of all seismic sources.
Work Criteria:
High pressure air flows continuously into the upper chamber
and through the shuttle into the lower chamber Opening the
solenoid valve puts high pressure air under the upper shuttle
seat, causing the shuttle to move upward, opening the lower
chamber and allowing its air to discharge through the ports to
form a bubble of high pressure air in the surrounding water.
https://www.youtube.com/watch?v=iMBq4xFNYU0

4. Airgun

5. 1- Dynamite.
In the past and before the technology revolution, companies
used to use the Dynamite as seismic energy source in the
marine acquisition. Then and due to its bad and dangerous
effect on the environment and marine lives companies
started to search another substitutes.
Non-Explosive Sources
In which no explosive material is used but mechanical
Devices are used to generate the seismic energy.
These sources are: 1- Water gun.
2- Boomer.
3- Sparker.
4- Chirp System.

6. 1- Water gun:
are adaptations of air guns to avoid the bubble pulse
problem. The compressed air, rather than being released into
the water layer, is used to drive a piston that ejects a water jet
into the surrounding water.

7. 2- Boomer.
Comprise a rigid aluminum plate attached below a heavy
duty electrical coil by a spring-loaded mounting. A
capacitor bank is discharged through the coil and the
electromagnetic induction thus generated forces the
aluminum plate rapidly downwards, setting up a
compressional wave in the water.
https://www.youtube.com/watch?v=benSICqJfAo

8. 3- Sparker.
- Devices for converting electrical energy into acoustic
energy. The sparker pulse is generated by the discharge of a
large capacitor bank directly into the sea water through an
array of electrodes towed in a frame behind the survey
vessel.
- This electrical discharge leads to the formation and rapid
growth of a plasma bubble and the consequent generation of
an acoustic pulse. For safety reasons, sparkers are
increasingly being replaced by other sources.

9. 4- Chirp System.
Are electro-mechanical transducers that produce an
extended, repeatable, source waveform which allows
greater energy output. This longer signal can be
compressed in processing to give greater resolution and/or
better signal-to-noise ratio.

10. Reference
• An introduction to applied and environmental geophysics,
seismic energy sources, JOHN M.REYNOLD 1997.
• An introduction to geophysical exploration, seismic data
acquisition systems, Philip Kearey, Michael Brooks, Ian
Hill,2002.
• USGS OFR 02-002: Seismic Data discussion.
• http://en.wikipedia.org/wiki/Seismic_source.
• http://www.appliedacoustics.com/sub-bottom-profiling.
• https://nees.org/warehouse/photos/project/516/experiment/
825.
• http://ontario
geofish.blogspot.com/2009_04_01_archive.html