The Tanzanian well encountered significant and unexpected gas shows in a zone above its primary target, prior to a drilling set-back which will now require a sidetrack to be drilled.
() has confirmed another notable helium gas show in the Tai-1 well, which is now being sidetracked due to a setback to the programme in Tanzania.
The gas shows were encountered above the well’s primary target zone, with the shows seen between a depth of 552 metres to 561 metres, and, were observed visually at surface as bubbles in drilling mud.
Prior to reaching the main target the well ran into trouble as a drill pipe was lost into the hole at 561 metres and contractor Mitchell Drilling, unable to retrieve the pipe, will now sidetrack the well from a depth of 483 metres.
“The identification of helium gas shows in the Red Sandstone group between 552 and 561 metres is another unexpected, but positive result as this zone was previously considered to be of low prospectivity,” said chief executive David Minchin. “This gas show, along with our earlier reported gas show announced on 22nd June, demonstrates a working helium system and supports helium prospectivity for additional gas shows throughout the stratigraphy.”
Minchin added: “The delay caused by the loss of drill string in the midst of the drilling is unfortunate, however contingency plans have been implemented to sidetrack from above the lost pipe and continue drilling to test both the Red Sandstone gas show and priority target horizons beneath.
“This option allows us to utilise the existing 483 meters of already completed drilling rather relocating to a new location.
“With the above indicators already identified we look forward to a successful completion of drilling on this target location.”
The Tai-1 well is part of the Rukwa project which comprises more than 20 helium prospects and with resources estimated pre-drill at a potential 138bn cubic feet is seen as one of the largest helium projects in the world.