| 摘要 |
<p>LAND SEISMIC SOURCE METHOD AND APPARATUS INVENTOR: STEPHEN V. CHELMINSKI Land seismic exploration method and system for generating and transmitting powerful seismic impulses into the earth from an air gun mounted in a housing having an impulse-transmitting diaphragm movably mounted below the housing with a reaction mass plate positioned above the diaphragm. Initially, the diaphragm is positioned firmly against the earth coupled to the earth in good impulse transmitting relationship, and the air gun is charged with highly pressurized gas. Then, the gun is fired, abruptly discharging the confined pressurized gas into the norrow horizontal interface region between the reaction mass plate and the diaphragm, and this released gas suddenly expands in the interface region for abruptly driving the diaphragm downwardly against the earth, thereby generating a powerful seismic impulse transmitted downwardly into the earth. The rapid expansion of the discharged gas between the reaction mass and the diaphragm causes intensely powerful seismic impulses to be transmitted into the earth. The apparatus includes a novel air gun which comprises a container having a firing chamber for holding a charge of pressurized gas, a movable shuttle for suddenly discharging the pressurized gas having an upper piston and a lower piston with a hollow member connecting them and a novel pedestal assembly carrying said shuttle is mounted from the top of the housing and extends down into the hollow member. A resilient pad or bumper is mounted centrally in the diaphragm to cushion the lower piston in case it plunges down into contact therewith.</p> |
