Concur t4p. in fact you always get elevated background gas...

Concur t4p. in fact you always get elevated background gas readings when drilling through coaly formations. Its generated internally ie biogenically within the coals themselves. If you get enough C1's ie methane within fracture zones and its shallow enough to extract then you have a potential CBM play.

If there is a deeper source feeding the Tirrawara then some may bleed up into the seal ie Purni fmn. ....there are eg very minor C5's ie the more liquid fraction.

However in my view the Permian Tirrawarra sst if they are present have always been my most primary target as they are the time equivalent to prolific Permian Tirrawara etc reservoirs in the Cooper basin. The shallower reservoirs are Eromanga Basin equivalents and are obviously not deep enough as in Central QLD for example to generate significant hydrocarbon.

Today might be the day...good luck all!