Apparatus for and method of controlling the firing of seismic sound sources

Claim 1

A control system for firing a plurality of seismic sound sources by respective firing commands in response to system triggering, comprising: a means for presetting a variable firing command delay with respect to system triggering for each of said sound sources; a means for determining the time elapsed after system triggering; a means for detecting a coincidence between the time elapsed after system triggering and said preset firing command delay for each of said sound sources; a means for generating a firing command signal for firing each of said sound sources in response to the respective detected coincidences; a source of gated clock pulses; and a means for displaying a count representing the overall firing delay time with respect to system triggering for each of said sound sources comprising: a firing delay register means associated with each of said sound sources coupled to said source of gated clock pulses for accumulating a count representing elapsed time after system triggering; a gate means responsive to the firing of each of said sound sources for terminating the further accumulation of the count in each of said firing delay register means; and a means for displaying the accumulated count in each of said firing delay register means.

Claim 4

A method of operating a control system for firing a plurality of seismic sources, comprising the steps of: presetting variable firing command delays for said respective sound sources; triggering a firing cycle for said sound sources; determining the elapsed time after triggering the firing cycle; generating firing commands for said respective sound sources when the elapsed time equals the firing command delays; determining the system firing delays represented by the elapsed time between triggering of the firing cycle and firing of said respective sound sources; and displaying said system firing delays for said respective sound sources.

Claim 5

A method of operating a control system for firing a plurality of seismic sources, comprising the steps of: presetting variable firing command delays for said respective sound sources; triggering a firing cycle for said sound sources; determining the elapsed time after triggering the firing cycle; generating firing commands for said respective sound sources when the elapsed time equals the firing command delays; determining the system firing delays represented by the elapsed time between triggering of the firing cycle and firing of said respective sound sources; and displaying said system firing delays for said respective sound sources.

Claim 7

A method of operating a control system for simultaneously or sequentially firing a plurality of pneumatic sound sources in which the sequence of the actual firing times of the sound sources are not identical with the sequence of the firing commands applied to the respective sound sources, said difference in sequences being due to differences in the characteristic firing delays of the sound sources, comprising the steps of: generating a system firing command; presetting variable firing command delays for said sound sources; generating source firing commands for firing each of the sound sources, said source firing commands being delayed in time from said system firing command by the amount of the respective preset firing command delays; generating time break signals upon the actual firing of said sound sources; determining the elapsed time between the system firing command and the time break for each sound source, said elapsed time representing both the preset firing command delay and the characteristic firing delay for such source; and adjusting said firing command delays to compensate for changes in the characteristic firing delays of the respective sound sources such that the elapsed times between generation of said system firing command and the actual firings of the respective sound sources are maintained simultaneous or in the desired sequence.

Claim 8

A method of operating a control system for simultaneously or sequentially firing a plurality of pneumatic sound sources in which the sequence of the actual firing times of the sound sources are not identical with the sequence of the firing commands applied to the respective sound sources, said difference in sequences being due to differences in the characteristic firing delays of the sound sources, comprising the steps of: generating a system firing command; presetting variable firing command delays for said sound sources; generating source firing commands for firing each of the sound sources, said source firing commands being delayed in time from said system firing command by the amount of the respective preset firing command delays; generating time break signals upon the actual firing of said sound sources; determining the elapsed time between the system firing command and the time break for each sound source, said elapsed time representing both the preset firing command delay and the characteristic firing delay for such source; and adjusting said firing command delays to compensate for changes in the characteristic firing delays of the respective sound sources such that the elapsed times between generation of said system firing command and the actual firings of the respective sound sources are maintained simultaneous or in the desired sequence.

Claim 9

A system for marine seismic exploration, comprising: a plurality of pneumatic sound sources having characteristic delay times from the application of a source firing command to the actual firing of the source sound which vary with usage, comprising: means for generating a system firing command; a source of gated clock pulses triggered by said system firing command; a first counter having an input coupled to the output of said source of gated clock pulses for accumulating a count corresponding to the time elapsed after generation of said system firing command; means for presetting a variable firing command delay for each of said sound sources; a coincidence detector with a first input coupled to the count output of said first counter and a second input coupled to the variable firing command delays for generating a source firing command for each of said sound sources upon the coincidence between the count in said first counter and the preset firing command delay for the respective sound source; means for generating a time break upon the actual firing of said sound sources; second counters for each of said sound sources having inputs coupled to the output of said source of gated clock pulses for accumulating counts representing the elapsed time after generation of the system firing command; gate means responsive to said time break signals for terminating the further accumulation of counts in each of said second counters; and means for displaying the accumulated count in each of said second counters whereby the variable firing command delays for each of the sound sources may be adjusted to compensate for variations in said characteristic delay times so as to permit the desired sequence of sound source firings to be maintained.

Claim 10

A system for marine seismic exploration, comprising: a plurality of pneumatic sound sources having characteristic delay times from the application of a source firing command to the actual firing of the source sound which vary with usage, comprising: means for generating a system firing command; a source of gated clock pulses triggered by said system firing command; a first counter having an input coupled to the output of said source of gated clock pulses for accumulating a count corresponding to the time elapsed after generation of said system firing command; means for presetting a variable firing command delay for each of said sound sources; a coincidence detector with a first input coupled to the count output of said first counter and a second input coupled to the variable firing command delays for generating a source firing command for each of said sound sources upon the coincidence between the count in said first counter and the preset firing command delay for the respective sound source; means for generating a time break upon the actual firing of said sound sources; second counters for each of said sound sources having inputs coupled to the output of said source of gated clock pulses for accumulating counts representing the elapsed time after generation of the system firing command; gate means responsive to said time break signals for terminating the further accumulation of counts in each of said second counters; and means for displaying the accumulated count in each of said second counters whereby the variable firing command delays for each of the sound sources may be adjusted to compensate for variations in said characteristic delay times so as to permit the desired sequence of sound source firings to be maintained.