CAPE TOWN- South Africa said on Tuesday it had hit pockets of shale gas during test drilling in the semi-desert Karoo region.

A decade ago the Karoo sparked intense interest from companies including Shell, Sasol and Falcon Oil & Gas FO.V , but farmers went to court to challenge any drilling in the ecologically-sensitive region, which saw enthusiasm wane amid regulatory uncertainty.

"The first pocket of gas was intercepted at 1,734 metres with a further substantial amount intercepted at 2,467 meters spanning a depth of 55 metres," South African energy minister Gwede Mantashe said during his budget vote in parliament.

A total of 34 gas samples had been bottled and taken to laboratories, he said, after government's Council for Geosciences set out to drill a 3,500 meter stratigraphic hole in the Karoo to establish and test the occurrence of shale gas.

In 2017, geologists at the University of Johannesburg and three other institutions estimated the gas resource in the Karoo was probably 13 trillion cubic feet (tcf), the bottom of a range of estimates that had put deposits between 13 tcf to 390 tcf.

In 2015, the U.S. Energy and Information Administration (EIA) estimated the Karoo Basin’s “technically recoverable shale gas resource” at 390 tcf, then making it the 8th largest in the world and second largest in Africa, behind Algeria.

(Reporting by Wendell Roelf Editing by David Goodman and Alexander Smith) ((wendell.roelf@thomsonreuters.com; +27 21 461 3523;))