Helium One Global Ltd has completed drilling the Tai-1A exploration well to a depth of 1,121m but poor hole conditions prevented logging below 882m at its 100% owned Rukwa project in Tanzania.
KAROO FORMATION
The company said that helium shows had been identified in all three target formations and encountered over five intervals in the Karoo Formation.
A 130m thick claystone unit was encountered above the top Karoo sands, indicating good seal presence for the Karoo reservoir.
The company added that wireline logging of the uppermost Karoo indicated good reservoir potential with 15-20% porosities.
However, Helium shows within the deeper and thicker sandstone units of the main Karoo reservoir were not able to be logged due to poor and deteriorating hole conditions.
This has left the main Karoo Formation unlogged.
Petrophysical analysis indicates no free gas in the uppermost thinly bedded Karoo sands associated with helium shows.
The results of Tai-1A will be evaluated and incorporated into the company’s exploration strategy which might include redrilling Tai to test identified targets
EXPLORATION
Chief executive David Minchin said that the company was encouraged to see multiple zones with helium shows while drilling through the Karoo Formation.
“Frustratingly, due to poor and deteriorating hole conditions, including large washouts across much of the Karoo, we were not able to run wireline tools downhole beyond 882m and have subsequently not been able to log the main Karoo Formation.
“Petrophysical analysis indicates that these helium shows are associated with gas-cut-brine or ‘fizz-gas’, which is formation water saturated with helium.
“These were the only helium shows that we could reach with wireline tools.
“With deteriorating hole conditions and no free gas identified we could not drill stem test at Tai-1A, leaving untested shows.
“We have learnt a lot about the subsurface of the Rukwa Basin which we can carry forward into planning our ongoing exploration programme.”