Real–Time Marine Seismic Acquisition QC
What is Marine Real–Time QC and Why Do I Need It?
Real–time QC is onboard seismic source and data quality control as soon as the data is received during marine seismic acquisition. It is aimed to identify any problems with seismic acquisition at the very same moment when they happen. This allows seismic crew fixing the problems immediately, minimizing related loss of operational time and money. Nowadays RT QC is the industry standard for marine seismic operations.
Typical real–time QC products include the following:
- Source control products: near–field hydrophone signature, bubble peak amplitude, time and period maps and plots, source towing depth plots, flip–flop source identity plots.
- Data control products: shot gathers, near–trace gathers, SOR/EOR/TARGET RMS amplitude maps, signal–to–noise ratio map, real–time 2D CMP/CSS stacks, frequency plots.
This set of products helps to control most of things happening on board related to seismic acquisition. By monitoring them, QC personnel and/or observers can easily identify out-of-spec issues like bad shots, dead or weak channels, source air leakages, misfires, flip–flop source identity loss, low signal–to–noise ratio, strong noises, etc. Many of these issues require immediate action and reporting.
The software runs on a PC, saving processing time of your server nodes. It connects to the data storage and input a shot record as soon as it is written. Each shot is read only once, to avoid network overload. After a shot is loaded into the local RAM of the PC, it is input to the pre–defined QC flows that all run in parallel locally. All real–time displays run and update locally as well, without slowing down the network.
This, along with the optimized processing algorithms, allows QC of the data from thousands of channels in true real–time, (typical delays are less than 1 minute) using just an good modern PC with a multi–core CPU, 64–bit Windows OS and several monitors. Compare this to some conventional QC packages, which claim to be real–time, while in practice have dozens of shots delayed even when working on a powerful Linux cluster…
Some examples of QC products are below:
Shot gather display
Standard fully customizable shot gather display.
A user–defined number of shots can be stored in memory and reviewed during acquisition.
Spectrum comparison for a number of shots
Several noisy shots can be seen at the start of the profile.
RMS amplitude map
Horizontal scale is shot number, vertical—channel number. Notice purple stripes on the image. The horizontal one indicates that channel 55 is dead, the vertical one—that shot number 1360 was bad. Purple areas around channels 200–240 indicate week channels due to weather conditions. Just one amplitude map can tell us a lot about what is happening onboard!
All QC images are saved to pre–defined folders automatically after each line and stored in structured order, from where can be easily imported to an EOL report.
Furthermore, all QC results can be saved to the processing project database, to be later played back or exported into SEG–Y files.