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interformational and intra-reservoir fluid cross-flows forming various
hydrochemical, hydrodynamical, thermal, isotope and other anomalies 1 .
This discharge modification contrasts with the Apsheron oil and gas
area. There, the hydrochemical profile in the Middle Pliocene Productive
Sequence is inverted in all fields. This is a result of the ascending depth ori-
gin alkaline ground water (foreign to the section) moving through faults.
A similar situation is recorded over the east flank of the basin, in the West
Turkmenistan (Balkhan area) and especially in the Lower Kura area (the
west flank). The vertical water movement is clearly traced there by hydro-
chemical and hydrodynamic anomalies, not only in the Pliocene interval
but also in the ground water of the overlying Quaternary complex (left
bank of the Kura River - Southeastern Shirvan) 2 .
Data of the surface and depth water-shows in the South Caspian Basin
together with their consistent association with faulted structural forms
make apparent a focal variety of ground water discharge in the region's
Mesozoic section and its prevailing realization through systems of tec-
tonic unconformities, mud volcano eruptions, etc. The scale of this drain-
age, as it follows from the previous chapters, is controlled first of all by the
fault conductivity on individual structures and by the tectonic nature of
higher order structural elements. Quite demonstrative in this respect are
the Apsheron and Balkhan regions with maximum, for the region, devel-
opment of fault tectonics and, respectively, underground fluid discharge
amount.
Deep waters' and surface water-shows' hydrochemical specifics in the
South Caspian Depression reveal their clear differentiation by the ion-salt
1 A convincing example of this kind of ground water discharge are the so-called
“crestal” waters in the I st horizon of the Kyurovdag Field, in the PK Formation of
the Surakhany Field and in the NKP and PK formations of the Sangachaly-More -
Duvanny-More - Bulla Isl. Field. These waters occupy crestal portions on the
structures and, with their high waterhead, push the hydrocarbon accumulations
on the flanks and plunges. In their chemical composition, they are different from
the accumulation aquifer, deeper subsided waters in their higher alkalinity and
lower salinity (Gurbanov, Moldavsky and Rachinsky, 1966; Khalilov, Dadashev
and Rachinsky, 1982).
2 Next to the Kura River channel in the area of low-salinity ground waters there
are drastically distinctive areas with total salinity jumping up compared to the
background values of 15-20 to 265 (Kyurovdag), 117 (Karabagly), 165 mg-equiv.
(Babazanan), etc. These areas usually coincide with most faulted crestal areas of
local highs. Importantly, the ground water chemical composition there is identical
to those of the underlying Productive Sequence (Mustafayev, 1967).
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