This conversion seems to represents some sort of transformation of geospatial data done using Petrel software, but maybe it is not possible at all. No further information about this particular conversion could not be found or verified.
Convert SEG-Y geophysical data file to Petrel compressed seismic data.
We have found one software suitable in our database for this conversion.
Microsoft Windows software - convert segy to zgy on Windows
Petrel is a software application intended to aggregate oil reservoir data from multiple sources.
Convert from segy file
to zgy file
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.