Geology Reference
In-Depth Information
by state structures of the interested countries, there was some political
(geopolitical) component (Adams, 2000).
On the other hand, these high numbers as well as great geologic expec-
tations may be viewed as a result of insufficiently substantiated extrapola-
tion into the future of exploration and appraisal successes in 1960-1980.
During that period the largest South Caspian fields were discovered by a
limited number of exploratory wells with relatively poor single-fold reflec-
tion seismic and correlation refraction seismic mapping. (These fields
are Sangachaly - Duvanny-More - Bulla Isl., Bulla-More, Peschany Isl.,
Bakhar, Neftyanyye Kamni, Gyuneshli, Chirag, Azeri, Kyapaz, Livanov
Bank East, Barinov Bank, Zhdanov Bank, Gubkin Bank and LAM Bank.)
However, the exploration and appraisal results of 1995-2006 do not
provide reasons for optimistic forecasts. During that period, the offshore
operations were conducted under 18 production-sharing agreements
(PSA) between Azerbaijan (15), and Turkmenistan (3) governments
and foreign companies. As of January 1, 2006, out of those contracts in
Azerbaijan, three were active, two were suspended due to an unsolved bor-
der dispute with Iran, and 10 were terminated after unsuccessful testing; in
Turkmenistan all three contracts were active (Table 11.2).
An important distinction regarding the subsequent events was that at
the time of contract execution, all operators had practically complete pack-
ages of geologic data accumulated over years of exploration and appraisal
in the region; almost all contract blocks and prospects were covered prior
to drilling by 2D and 3D seismic surveys. This data enabled, in consider-
ation of the Basin's specifics, sufficiently reliable modeling of natural reser-
voirs-traps and spudding first exploratory and appraisal wells in optimum
locations for the discovery of hydrocarbon accumulations on local highs.
During the stated period, drilling on the Azerbaijan shelf was conducted
on 15 structures. Only on one of those (Shahdeniz), British Petroleum
(ВР) discovered by the first advance appraisal well SDA-01 a large gas and
condensate field with gas reserves about 1.2 TCM. (The exploratory drill-
ing of this prospect was begun as early as the 1980's by the Azerbaijan
organizations. Local geologists who substantiated the need to drill never
doubted its high gas potential. They were unable to make this discovery
independently only due to limited technical capability of drilling opera-
tions in great water depths.) On the remaining 14 prospects, 16 wells were
drilled, 3,840 to 7,087 m deep. Seven of those wells tested hydrocarbon
flows (Ashrafi, Dan Ulduzu, Karabakh and Nakhchyvanly in the eastern
North Apsheron zone of highs of the Apsheron Archipelago and Zafar in
the southern folding of the Baku Archipelago - north of the deep-water
depression). These discoveries, however, were considered by the operators
