Dear all,

I'm new geophysicist and starting use Petrel Software.
I had a problem about import SEGY seismic data in petrel.
The SEGY Import dialog box open and then I examined the header file to determine the appropriate Inline, Crossline, X, and Y byte locations, and enter them into the byte position boxes. QC the byte locations by selecting an appropriate number of traces, and pressing the “scan” button. Typically, the Inline position will resemble a stairstep pattern and Crosslines resemble a sawtooth pattern.
I don't know why Inlines are stairstep pattern and Crosslines are sawtooth pattern?
Please help me to understand about this pattern.

Thanks and regards.
Dong