Helium One Global Ltd has completed the drilling of its first well, Tai-1A, at the Rukwa helium project in Tanzania.
Chief executive David Minchin described the well as encouraging – as it encountered helium shows in a total of five intervals of the Karoo formation including all three pre-drill targets.
“We are encouraged to see multiple zones with helium shows whilst drilling through the Karoo Formation. Tai-1 has successfully identified helium shows within all three target formations which confirms the presence of a working helium system in the Rukwa Basin,” Minchin said in a statement.
Wireline logging of the uppermost interval indicated good reservoir potential, with porosities of 15 to 20%, but petrophysical analysis indicated no free gas in this interval. It was the only interval of the five that could be logged and tested further as the programme was hindered by poor and deteriorating hole conditions.
The Tai-1A results will be evaluated and incorporated into the company’s ongoing exploration strategy, which may include the re-drilling of Tai to test the identified targets.
“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,” Minchin explained.
“Thinly-bedded sands in the uppermost Karoo that we were able to log have no indications of free gas.
“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.
“Deeper show intervals identified in thicker and cleaner sandstone units of the main Karoo Formation were not logged. 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, which may include redrilling of Tai prospect to test identified targets.”