Geology Reference
In-Depth Information
The similar type hydrocarbonate-sodium waters in all other Mesozoic units
are foreign, injected from the mentioned interval (Akhundov, Mekhtiyev
and Rachinsky, 1976; Durmishyan
,
Muradyan and Rachinsky
,
1973).
The above conclusion is supported by data on waters in the Mesozoic
of the east flank of the South Caspian Basin. New data were recently
collected by Kolody and Kudelsky, (1972) and by other scientists about
the hydrogeology in the Kopet-Dagh, Great Balkhan mountains and in
the Aladag-Messerian zone of highs adjacent to the West Turkmenian
Depression. These data indicate that there the Post-Neocomian Mesozoic
section contains high-salinity chlorine-calcium waters. As an example,
from the Cretaceous rocks in the Sumbar River valley (Kopet-Dagh) were
obtained flows of chlorine-calcium waters with salinity of 17-53 g/l; from
the Cretaceous-Paleogene rocks at the Syrtlanli prospect, waters with
salinity over 50 g/l; from the Cenomanian at the Suiji prospect, 53 g/l; and
at the Boyadagh prospect, from the uppermost portion of the unsubdi-
vided Aptian-Cenomanian complex, waters with salinity over 100 g/l (Ver-
Wiebe, 1959; Kolody, 1983).
Ground water flows from the
Paleogene-Miocene
complex were
obtained in the SW Kobystan (Donguzdyk, Gidjaki, Cheildagh, Nardaran-
Suleyman, Adjiveli, Arzani-Klych, Ragim and Sundi prospects) and in the
northwestern (Djorat, Khurdalan, Binagady and Chakhnaglyar prospects),
western (Karaeybat, Sulutepr, Shubany, Karadagh, Kushkhana, Gyulbaht
and Gyuzdek prospects), central (Khorasany, Kyurdakhany) and eastern
(Artem island) Apsheron Peninsula (Akhundov, Mekhtiyev and Rachinsky,
1976; Rachinsky, Vezirova and Friedman, 1972).
Waters in the
Maikopian
Formation (Oligocene-Lower Miocene)
include all hydrochemical types. Their salinity varies, 20 to 130 mg-equiv.
(5.7-37.2 g/l). The salinity range of up to 70 mg-equiv. contains only hydro-
carbonate-sodium and sulphate-sodium waters; higher values are associ-
ated with chlorine-magnesium and chlorine-calcium types. Except for the
sulphate-sodium waters (where the sulphate content is 5-8 mg-equiv.), the
Maikopian waters are practically no-sulphate; wherever present, it is an
indication of the reservoir water mixing with the infiltrating surface water.
Total alkalinity range is 1-9 mg-equiv. Soluble salts of organic acids are
recorded in alkaline waters only (provided the reservoir is commercially
hydrocarbon-saturated). Calcium content does not exceed 4 and magne-
sium 3 mg-equiv. The sodium and potassium content ranges between 9
and 60 mg-equiv. The primary alkalinity factor in the hydrocarbonate-
sodium varieties is 0.1 to 40%-equiv.; the secondary salinity factor in the
hard waters is 0.1 to 25%-equiv. Typical of this complex is elevated second-
ary alkalinity of up to 10%-equiv. (Tables 2.1, 2.4).
