Geology Reference
In-Depth Information
С
2
), contingent (lower part of C
2
and upper part of C
3
) and prospective
resources (lower part of category С
3
and
all of category D). The existing
estimates of hydrocarbon potential (the sum of proved reserves, contin-
gent and prospective resources, Russian categories А+В+С
1
+С
2
+С
3
+D
1
) in
the basin are extremely disparate and differ sometimes by the order of the
magnitude. Over the recent period, this situation is the reason for a signifi-
cant extent of low exploration and appraisal success rate in the region and
a high degree of geologic risks.
Table 11.1 includes expert estimations of commercial hydrocarbon
potential by the country and Basin as a whole and their dynamics in time.
In the view of all experts, the gas component of HC resources exceeds the
oil component more than two times. A broad range of estimates is typical:
Azerbaijan, 2.76-30.00; Turkmenistan, 1.23-16.50; Iran, 1.00-3.09; Basin
as a whole, 6.66-49.59 BT of oil equivalent. A clear trend of their decrease
in time is evident as geologic information becomes more complete.
Azerbaijani, Turkmenistan and Iranian geologists (Bagir-Zadeh,
Kerimov
et al
., 1987; Bagir-Zadeh and Narimanov, 1988; Kerimov, Gajiyev
and Gasanov, 1999) and Western and Russian experts (Adams, 2000;
Glumov
et al
, 2004) strongly believe that all (or most) structures in the
practically unstudied deep-water zone of the Southern Caspian Sea and
Turkmenistan structural terrace are potential fields. (The structures in the
deep-water area are located in the South-Apsheron trough folding, central
and southern Baku Archipelago, Abikh Swell, Sary-Chikishlyar structure
belt, and Lenkoran-Gorgan trough). In recent cases, this approach resulted
in not exactly stringent identification of the recoverable hydrocarbon
potential in the individual countries and Basin as a whole (Table 11.1).
The proved hydrocarbon reserves in Iraq were determined at 18.92; UAE,
19.47; Kuwait, 15.84; and even Iran, 43.65 and Saudi Arabia, 43.40 BT of oil
equivalent (Official Energy statistic from U.S Government, 2005).
It is important to note that the maximum potential values by the coun-
tries are claimed mostly by state organizations (SOCAR, State Company
“Turkmenneft”, Iranian Ministry of Oil), by foreign companies working on
orders (US Western Geophysical), by US federal bodies (US Department
of Energy, US Department of State) and by analysts of the European Union
(INOGATE Program of the European Commission) mostly in the early
post-Soviet period (1992-1995). At the same time, minimum potential
values were claimed by independent experts not on contract with state
bodies. These discrepancies could not have been caused by the extent of
knowledge due to relatively small amounts of exploration and appraisal
operations in the region during 1990-2005. That is why it is not unreason-
able to assume that in the maximum values of the Basin's potential claimed
