System for suppressing multiple pulse in marine seismic sources by injection of additional air

Claim 1

An air-operated seismic source for forming an air bubble underwater to thus generate a desirable seismic pulse caused by the initial expansion of the bubble, while suppressing undesirable secondary pulses caused by the first and subsequent contractions of the bubble, comprising the combination of; air source means disposed above the surface of the water, said air source means including at least one compressed air source for supplying air at a pressure of the order of 2,000 pounds per square inch; air ejector means including an air valve means disposed at a selected depth beneath the water surface and containing confined air at substantially said pressure, said air ejector means being coupled to said air source means and adapted to introduce a first burst to air into the surrounding water to define the initially expanding bubble; said air ejector means containing a second quantity of air under selected pressure beneath the water surface and being further adapted to introduce the second quantity of air directly from the position under the surface of the water into the expanding bubble as it approaches its maximum diameter; and trigger means including a signal time delay means coupled to the air ejector means to operate the air ejector means in selected timed sequence to provide the first burst and the second quantity of air directly from the air ejector means into the water.

Claim 5

A method for forming a desirable seismic pulse caused by the initial expansion of an air bubble while suppressing undesirable secondary pulses caused by the first and subsequent contractions of the bubble under water, comprising the steps of; compressing a single quantity of air at a relatively high pressure of the order of 2,000 pounds per square inch; confining the high-pressure air in a single air ejection device disposed at a selected depth beneath the water surface; ejecting an amount of the confined air at the selected depth from said single air ejection device to provide the initially expanding air bubble; and subsequently ejecting in timed sequence another amount of the confined air from the single air ejection device directly into the expanding bubble as it approaches its maximum diameter, to thus reduce said contractions.

Claim 6

A method for forming a desirable seismic pulse caused by the initial expansion of an air bubble while suppressing undesirable secondary pulses caused by the first and subsequent contractions of the bubble under water, comprising the steps of; compressing a single quantity of air at a relatively high pressure of the order of 2,000 pounds per square inch; confining the high-pressure air in a single air ejection device disposed at a selected depth beneath the water surface; ejecting an amount of the confined air at the selected depth from said single air ejection device to provide the initially expanding air bubble; and subsequently ejecting in timed sequence another amount of the confined air from the single air ejection device directly into the expanding bubble as it approaches its maximum diameter, to thus reduce said contractions.

Claim 7

A method for forming a desirable seismic pulse caused by the initial expansion of an air bubble while suppressing undesirable secondary pulses caused by the first and subsequent contractions of the bubble under water, comprising the steps of; compressing a first quantity of air at a relatively high pressure of the order of 2,000 pounds per square inch, and a second quantity of air at a relatively low pressure of the order of 150 pounds per square inch; confining the high and low-pressure air respective air ejection devices disposed at a selected depth beneath the water surface; ejecting an amount of the confined high-puressure air at the selected depth to provide the initiaLly expanding air bubble; and subsequently ejecting in timed sequence the confined low-pressure air directly into the expanding bubble as it approaches its maximum diameter, to thus reduce said contractions.

Claim 8

A method for forming a desirable seismic pulse caused by the initial expansion of an air bubble while suppressing undesirable secondary pulses caused by the first and subsequent contractions of the bubble under water, comprising the steps of; compressing a first quantity of air at a relatively high pressure of the order of 2,000 pounds per square inch, and a second quantity of air at a relatively low pressure of the order of 150 pounds per square inch; confining the high and low-pressure air respective air ejection devices disposed at a selected depth beneath the water surface; ejecting an amount of the confined high-puressure air at the selected depth to provide the initiaLly expanding air bubble; and subsequently ejecting in timed sequence the confined low-pressure air directly into the expanding bubble as it approaches its maximum diameter, to thus reduce said contractions.