RE: Helium generation31 Aug 2021 13:48
It's about traps AND reservoirs AND commerciality. Thick sandstones with 15-20% porosity make up most of the Karoo formations. We now know that these are overlain by 130m of siltstone. Thus we have the parent of all reservoirs with the parent of all traps, but at a depth of 1200m. Quite a way down to drill, but the gas will also be at a higher pressure, so more per given volume of reservoir. One hole here (in the right place identified by 3D seismic, drilled with the right rig) will provide a commercial source of He.
On the other hand, the near-surface Lake Bed Formation has only thin potential reservoirs, of limited areal extent - it was only 20m between Tai-1 & -2, but the sandstone had already pinched out into clay. How many of these shallow mini-reservoirs are you going to find? I have no idea what "geophysical techniques" will reliably locate such structures, perhaps the local medicine man with a forked hazel twig? How are you going to link all these together to channel the He/N mix to a concentrator that costs $50M? I just don't get this concept of shallow reservoirs ever being of commercial significance.
Better to spend the cash on 3D seismic of the leads previously identified and drill them with adequate kit. Three different trap types were originally going to be investigated - results from these really WOULD de-risk the whole Rukwa basin, as well as greatly increasing the chances of finding a real live commercial He reservoir.
I am concerned that the real objective of jabbing around at random with a water drill is in the hope of cheaply finding some free gas so that a 'discovery' can be declared. What we need is a discovery that leads smoothly to commerciality.
Just my highly opinionated view, of course - DM may have some data to back up his ideas, if so it would be nice to see it. By RNS, not a half-baked Twitter release. There, I will go and lie down now :-)