wa gas marekt tightens, page-8

It is certainly a tool of the future, and can now be used onshore also, although I am only aware of one significant contractor supplying this technology onshore. But I can't see it as a stand alone tool for some time yet, if ever, and it remains early days as they refine processing techniques and calibrating data. Essentially its best use is to rank structures that are identified by seismic. Surface geochemistry can be used in similar ways also, but results can be more ambiguous as the microseepage involved can take a rather indirect path to the surface for one thing.