Method and apparatus for utilizing time division multiple waveform transmitting
AssigneeExxonMobil Upstream Research Company
InventorsXinyou Lu, Scott C. Hornbostel, Dennis E. Willen
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Abstract
A method and apparatus of constructing a signal for a controlled source electromagnetic survey is described. In one embodiment, a method is described that includes determining a first waveform and a second waveform, the first waveform and second waveform related to a combined frequency spectrum and bandwidth associated with a geophysical survey line. Then, a signal is constructed by sequencing the first waveform with the second waveform. This signal may be utilized in a transmitter, which may be pulled by a vessel along the geophysical survey line.
Claims39
A method of constructing a signal for a source along a geophysical survey line for a controlled source electromagnetic survey comprising:
- determining a first waveform and a second waveform, the first waveform and second waveform related to a combined frequency spectrum and bandwidth associated with a geophysical survey line;
- determining a specific time interval for the compound waveform associated with the geophysical survey line;
- constructing a signal by a sequencing comprising sequencing the first waveform with the second waveform, thereby constructing a compound waveform having said combined frequency spectrum and bandwidth;
- calculating a proposed time interval for the compound waveform;
- adjusting the compound waveform if the proposed time interval is greater than the specific time interval;
- and
- repeating the signal over one or more different time intervals along the geophysical survey line.
A transmitter for constructing a compound waveform for a source along a geophysical survey line for a controlled source electromagnetic survey comprising:
- an antenna;
- and
- waveform creation logic coupled to the antenna and configured to:
- provide a plurality of base waveforms, wherein the plurality of base waveforms are related to a combined frequency spectrum and bandwidth associated with a geophysical survey line;
- determine or read from input a specific time interval for the compound waveform associated with the geophysical survey line;
- construct a compound waveform having a specific time interval by sequencing the plurality of base waveforms;
- calculate a proposed time interval for the compound waveform;
- adjust the compound waveform if the proposed time interval is greater than the specific time interval;
- and
- repeat the compound waveform at another time interval along the geophysical survey line.
A system for conducting a controlled source electromagnetic survey with a compound waveform for a source along a geophysical survey line comprising:
- a vessel coupled to a transmitter via a cable, the transmitter comprising:
- a transmission circuitry;
- and
- waveform creation logic coupled to the transmission circuitry and configured to:
- provide a plurality of base waveforms, wherein the plurality of base waveforms are related to a combined frequency spectrum and bandwidth associated with a geophysical survey line;
- determine or read from input a specific time interval for the compound waveform associated with the geophysical survey line:
- construct a compound waveform having a specific time interval by sequencing the plurality of base waveforms;
- calculate a proposed time interval for the compound waveform;
- adjust the compound waveform if the proposed time interval is greater than the specific time interval;
- and
- repeat the compound waveform at another time interval along the geophysical survey line;
- and
- at least one receiver configured to detect the compound waveform.
Dependencies are inferred from the claim text.