Shot by Shot Monitoring
We have also developed a shot-by-shot source monitoring platform that permits us to mitigate and manage many environmental conditions encountered during acquisition. It accounts for both the motion of the air guns through the water and the manner in which air bubbles rise through the water column.
Measurement is the first stage in understanding and managing variation. Near-field hydrophones mounted at every air gun are used to calculate the 'notional sources' where each is located. These can then be combined to describe the three-dimensional shot-to-shot variation in the emitted source wavefield.
These variations become more pronounced as the sea state deteriorates, and can complicate data processing. The use of calibrated shot-to-shot signatures can be beneficial during data processing.
- During acquisition, monitoring provides many real-time QC benefits and can help to identify problems such as air gun leaks.
- At the processing stage, the system makes it easy to spot and compensate for variations in source output, for example during undershooting or line turns.
One innovation leads to another
Shot-by-shot monitoring is one of the inspired ideas that facilitated PGS development of eSeismic, an innovation that uses both continuous source wavefields and continuous recording.