Geology Reference
In-Depth Information
the Galyugayev prospect). Water type is chlorine-calcium, total salinity is
182.6-495.1 mg-equiv. (53.1-143.3 g/l), secondary salinity factor is 8.4-
21.3%-equiv., sodium/chlorine ratio = 0.84-0.92.
The regional hydrochemical background in individual tectonic zones and
water horizons of the complex have the following total salinity and second-
ary salinity factor values: Chernogor monocline: Upper Jurassic, 240-250
mg-equiv. (70.6-73.5 g/l), 16-18%-equiv., Valanginian, 220-230 mg-equiv.
(64.7-67.6 g/l), 12-14%-equiv.; Sunzha anticlinorium: Upper Jurassic, 420-
430 mg-equiv., (123.5-126.5 g/l), 16-18%-equiv., Valanginian, 290-300 mg-
equiv. (85.3-88.2 g/l), 13-15%-equiv.; Tersk anticlinorium: Upper Jurassic,
400-410 mg-equiv. (117.6-120.6 g/l), 11-13%-equiv., Valanginian, 240-250
mg-equiv. (70.6-73.5 g/l), 8-10%-equiv.; Pri-Terek zone of highs: Upper
Jurassic, 480-490 mg-equiv. (141.2-144.1 g/l), 20-22%-equiv., Valanginian,
380-390 mg-equiv. (111.8-114. 7 g/l), 12-13%-equiv.
On the local structures positive deflections from the background values
(hydrochemical anomalies) - maximum salinity and secondary salinity fac-
tor values - are usually recorded in the most faulted restricted areas where
higher salinity waters invade from the underlying intervals spatially cor-
responding with zones and fault-blocks of commercial oil-gas-saturation.
In the fields within all horizons of the complex occurs a decrease in
total salinity and secondary salinity factor values with depth - from the
crests to the flanks and plunges of local structures - and an increase of the
same parameters down the section from the Valanginian Stage through
the Upper Jurassic. A similar change in salinity is observed also over the
trough area, south to north (from the Chernogor monocline to the Pri-
Terek zone) as the water reservoirs become deeper father from their sur-
face exposures (the north slope of the Caucasus Major).
In the
Hauterivian-Aptian
complex presented by clastic reservoirs (car-
bonate sandstones and siltstones) are also common the chlorine-calcium
type waters (Datykh, Zamankul, Karabulak-Achaluki, Sernovodsk,
Malgobek-Voznesenskoye, Ali-Yurt, Khayan-Kort and Galyugayev fields).
Their salinity range is 145.2-314.0 mg-equiv. (42.2-92.2 g/l), secondary
salinity factor 6.6-16.8%-equiv., sodium/chlorine ratio = 0.85-0.94.
The background values of these parameters in the individual zones
are: the Chernogor monocline 180-200 mg-equiv. (52.9-58.8 g/l),
12-14%-equiv.; the Sunzha anticlinorium 210-230 mg-equiv. (61.7-
67.6 g/l), 8-10%-equiv.; the Tersk anticlinorium 220-240 mg-equiv.
(64.7-70.6 g/l), 10-12%-equiv.; the Pri-Terekая zone 170-190 mg-equiv.
(50.0-55.9 g/l), 8-10%-equiv.
The ground water salinity and component composition distribution
over the area and in the section, and hydrochemical anomalies associated
