A seismic source
FIG. A-6. Air gun
. (a) 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 shuttle seat causing the shuttle to move upward, opening the lower chamber and allowing its air to flow out through ports to form a bubble of high-pressure air in the water. The size of a gun is the size of its lower chamber. (Courtesy Bolt Associates.)
(b) Sleeve gun; the sleeve around the gun slides back to release the air into the water.
(c) Photo of a sleeve gun. (Courtesy WesternGeco.)
that injects a Bubble of highly compressed air into the water.
Its frequency spectrum depends on the amount of air in the bubble, the air pressure, and the water depth (or water pressure).
Arrays of guns of different sizes are often used so that a broader frequency spectrum will be generated.
See also waveshape kit.
Air guns are also used in boreholes or pushed down into marsh after being modified to prevent mud, sand etc. from entering and fouling the air gun, and they are sometimes used in bags of water that are set on the ground surface for land work.
- ↑ Dragoset, W., 2000, Introduction to air guns and air-gun arrays: The Leading Edge, 19, 892–897. http://dx.doi.org/10.1190/1.1438741
- ↑ Caldwell, K. and Dragoset, W., 2000, A brief overview of seismic air-gun arrays: The Leading Edge, 19, 898–902. http://dx.doi.org/10.1190/1.1438744
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