Thru' a 'happy coincidence' Afghanistan also happens to border two Central
Asian countries, Turkmenistan and Uzbekistan, with very large natural gas
reserves. Of course, as is well known, Iran also happens to have enormous
proven natural gas reserves of about 812 trillion cubic feet (Tcf), which is
about 15% of the world's proven gas reserves. To have a feel of these
numbers, the United States consumed about 22.2 Tcf of natural gas last year.
The proven natural gas reserves in the U.S are about 167 Tcf.

Here is a brief extract from the EIA (Energy Information Administration; an
autonomous U.S. Govt. Agency) site for commercial energy related issues in
the Caspian region [  http://www.eia.doe.gov/emeu/cabs/caspian.html ]

"....The prospect of potentially enormous hydrocarbon reserves is part of
the allure of the Caspian region (includes Azerbaijan, Kazakhstan,
Turkmenistan, Uzbekistan, and the regions of Iran and Russia that are near
the Caspian Sea). Besides the 18-34 billion barrels currently proven, the
region's possible oil reserves could yield another 235 billion barrels of
oil. This is roughly equivalent to a quarter of the Middle East's total
proven reserves (however, the Middle East also has its own vast possible
reserves). Possible gas reserves in the Caspian region, including
Uzbekistan, are as large as the region's proven gas reserves, and could
yield another 328 trillion cubic feet (Tcf) of gas if proven.

Most of Azerbaijan's oil resources (proven as well as possible reserves) are
located offshore, and perhaps 30%-40% of the total oil resources of
Kazakhstan and Turkmenistan are offshore as well. Proven oil reserves for
the entire Caspian Sea region (total country reserves, not just for the
Caspian Sea itself) are estimated at 18-34 billion barrels, comparable to
those in the United States (22 billion barrels) and the North Sea (17
billion barrels). Natural gas reserves are even larger, accounting for
almost two-thirds of the hydrocarbon reserves (proved plus possible) in the
Caspian Sea region. Based upon proven reserves, Kazakhstan, Turkmenistan,
and Uzbekistan each rank among the world's 20 largest natural gas countries.
Overall, proven gas reserves in the Caspian region are estimated at 243-248
Tcf, comparable to North American reserves of 300 Tcf......"

You may also wish to check out some of EIA's country sites at
 http://www.eia.doe.gov/emeu/cabs/

Here are links for two of them:

1) Turkmenistan (pop. 4.5 million, area slightly larger than California)
 http://www.eia.doe.gov/emeu/cabs/turkmen.html

2) Uzbekistan (pop. 24.8 million, area slightly larger than California)
 http://www.eia.doe.gov/emeu/cabs/uzbek.html

regards,
-venkat