The latest way to make copies of the seismic data in real-time: diagram 1 and diagram 2. Watch stander's instructions for tape copy and brute stack. The data flow and computer interconnectivity are diagrammed here.Return to SIOSEIS examples Go to the list of SIOSEIS processes. Go to SIOSEIS introduction.Paul's watch notes and navigation are here.
The Syntron 3490E SEG-D tapes were reformatted to SEG-Y and written to two DLT tapes on computer Heezen. The tape copy script(s) is also a record of the changing streamer geometry. The script(s) also apply the streamer geometery and created rp numbers (SEG-Y trace header word 6). The type of geometry applied changed in mid-cruise from the user having to give the shot spacing (dfls or distance-from-last-shot) to automatically determining the each shot's location fron the real-time GPS. An explanation of sioseis' rp number calculation is given here.
Sonobuoys were recorded in Syntron channel set 2, trace 1. Channel set 2 was excluded in the tape copy script. The get_sonobuoy script collects all the trace 1s of channel set 2 in real-time and writes them to disk.
A real-time brute stack plot was done on grampus. This script used several newish features: Reading the pseudo-SEG-D data in real-time from "Seisnet"; application of a constant avenor gain (new avenor parameter HOLD) rather than agc or gains, and type 9 geometry (dfls for each shot computed from the real-time lat/long). Process SEGDDIN also creates and writes some shot information to a log file. Only the closest 3km (traces 241-480) were used and a velocity function that varied with the water depth. Before starting the stack script, for each line, sioseis needs to be told where the seisnet files are. The init_seisnet script assumes the seisnet PC computer writes to grampus' disk /export/home3/seisnet/0210/data/$DIR, where $DIR is the line-name entered into the seisnet computer and is the argument to this script.
Real-time qc plots from Seisnet were done with this script. This script has the seisnet-sioseis interface built in. The plot job should run in a different directory from all other sioseis jobs.
Constant velocity stack script prior to sioplt picking.
Velocity spectra script using Matlab.