Real–Time Marine Seismic Acquisition QC
What is marine real–time QC and why do I need it?
Real–time QC is dedicated for 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 to immediately fix the problems, minimizing related loss of operational time and money. Nowadays RT QC is the industry standard for marine seismic operations.
Typical real–time QC products are:
- Source control products: near–field hydrophone signature, bubble peak amplitude, bubble peak time, bubble time period, source towing depth, flip–flop source energy identity.
- Data control products: shot gathers, near–trace gathers, SOR/EOR/TARGET RMS amplitudes, signal/noise amplitudes, signal–to–noise ratio, real–time 2D stacks, frequency analysis.
This set of products controls most of the things happening on board, related to the seismic acquisition. By monitoring them, QC personnel and/or observers can easily identify “out of spec” issues like bad shots, bad or week channels, source air leakages, misfires, flip–flop source identity loss, low signal–to–noise ratio, strong noises, etc. Many of these issues requires immediate action and reporting.
The software 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 RAM of the local 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 or using any processing time of your server nodes.
This, along with the optimized processing algorithms, allows QC of the data from thousands of channels in true real–time, using just an average good modern PC with a multi–core CPU and 46–bit Windows OS. Compare this to some other known packages, which are supposed to run procedures in the real–time, while on practice have dozens of shots delayed even working on a 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 into a database, to be later played back or exported into SEG–Y files.