a probable 10-15 metre column of nitrogen and helium at the...

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   a probable 10-15 metre column of nitrogen and helium at the crest, helium-rich downhole samples calculated at 2-3% helium in exsolved gas and helium- rich gas bubbles in the drilling mud at multiple depths in both wells.

I don't know the answer to this, but to me there are three parts to the above, that's what the commas are for. First bit 10-15 metre column at the crest.
Sounds like a cap to me.

Mbelele-2 was spudded on 16 November at 0100hrs local time and similar to Mbelele-1 soon encountered helium-enriched gas bubbling in the mud system, initially at 140mMD, which may correlate laterally to the formation at Mbelele-1 that contained the probable nitrogen-helium gas cap at 85mMD

Also reference to a probable gas cap.

My assumption is that they have been at this a long time and they are excited, and know a lot more than I.
I understand that there are still some substantial issues to be addressed, and further clarification will be required, but the chances this is actually a discovery have just grown exponentially and be it right or wrong, for me, and this is not investment advice, its an easy buy.