By OGJ editors
HOUSTON, Mar. 15 -- Afghanistan's undiscovered oil and gas resource base is much larger than previously understood, said the US Geological Survey after a multiyear study.
The agency estimated mean undiscovered resources at 15.7 tcf of gas, 1.6 billion bbl of oil, and 562 million bbl of natural gas liquids. Most of the gas is indicated to be in the Amu Darya basin and most of the oil in the Afghan-Tajik basin.
The two basins cover a combined 200,000 sq miles in northern Afghanistan, and the USGS assessed 33,000 sq miles of that. It subdivided four petroleum systems into eight assessment units.
Formations with the greatest potential are, for gas, Upper Jurassic carbonate and reef reservoirs beneath an impermeable salt layer in relatively unexplored parts of northern Afghanistan and, for oil, Cretaceous to Paleogene carbonate reservoir rocks associated with thrust faulting and folding in the Afghan-Tajik basin.
A 1990 USGS report estimated that 4.74 tcf of gas and 80 million bbl of oil had been discovered in Afghanistan by 1980. It put estimated recoverables at 300 million bbl of oil, 9.6 tcf of gas, and 145 million bbl of condensate.
That report said most reservoirs would be 10,000-20,000 ft deep.
Part of that study sought to aggregate estimates of proved reserves in several fields discovered from 1957 to 1984. Most of the fields are no longer on production (see map, OGJ, Aug. 9, 2004, p. 32).
Afghanistan has sought to mount a licensing round, but no exploration is reported in the country in recent years.
The US Trade and Development Agency funded the study, which USGS conducted jointly with the Afghanistan Ministry of Mines and Industry.