SEAM contracted with Nexus Geosciences Inc. (NGI), now part of WesternGeco, to conduct quality control (QC) evaluation of all data delivered by the simulation vendor. The steps in the QC process were developed by the Execution Committee and approved by the Management Committee (see Appendix A, “Description of QC Services”). The data flow diagram in Figure 4 of in Chapter 1 illustrates the relationships of all the vendors, SEAM committees, and individuals involved. The QC vendor received compressed data from the simulation vendor on USB disk. The data were decompressed, and the QC process was initiated. Once data were passed through the QC process, the USB disks were sent to the storage vendor. During the decompression, traces that comprise the classic data sets were extracted. These were sent to Stew Levin, who stored and compiled these data and compressed them for long-term storage.
The quality-assurance protocol was designed to provide a thorough but timely assessment of data quality and model performance and to identify potential problems for correction. The procedure contains a number of steps to
Test quality of the numerical simulations, including evaluation for excessive amplitudes that may indicate numerical problems.
Ensure shots and traces are in their expected and correct locations.
Prepare fold maps.
Ensure no corruption of data during compression and loading of storage media that were used to transport data between simulation, QC, and data storage vendors.
Extract zero-offset traces, depth-migrate them, and overlay on the model. Raw zero.