Managing director Andrew Andrejewskis said line clearing is expected to be completed within the next week while the survey pegging is progressing well ahead of the recording crew.
The survey work covering about 428km began in late April and would be completed in about six weeks.
Half of the seismic work would provide detailed coverage over several leads and prospects in the Boorthanna Trough.
The second part of the survey is a regional 2D program aimed at determining the southward extension of the Boorthanna Trough.
The survey is the region's first such survey since the early 1980s
Andrejewskis said Sapex is aiming to drill two exploratory wells before the end of the year, subject to the completion of processing and interpretation of the data.
Sapex is also considering various options for funding the proposed drilling program.
Adelaide-based Sapex holds a 100% interest in the under-explored basin, with 65,000 square kilometres under seven granted PELs.