Geology Reference
In-Depth Information
and gas areas. Correlation between the mentioned parameters in these
accumulations results in the following conclusions:
t
The Productive Sequence's hydrocarbon saturation qualita-
tively and quantitatively is genetically connected with the
presence of low-salinity hydrocarbonate-sodium waters and
is a function of their presence.
t
Part of the Productive Sequence in the Apsheron oil and
gas area is saturated with alkaline waters. For this part the
correlation
β
i
=
f(A)
, while preserving general qualitative
direction, is drastically differentiated quantitatively for the
eroded (denuded) and uneroded structures. The first group
includes mostly diapirism-affected deeply eroded structures
in the Apsheron Archipelago and the second one, predomi-
nantly uneroded syndepositional highs on the Apsheron
Peninsula
2
.
t
In the first group of the structures, despite seemingly unfa-
vorable environment for the preservation of hydrocarbon
aggregations, at the same value of ground water primary
alkalinity factor the per unit volume oil-saturation is sub-
stantially higher compared with the second group.
t
Within the identified morphological groups of local struc-
tures the
β
i
3
=
f
(
А
) correlation has a clear unimodal nature
with the maximum at primary alkalinity factor of about
2
Some accumulations on uneroded structures (most frequently removed from the
NKP Fm. basal intervals) are in the area of correlation
β
i
3
=
f
(
А
) typical of the first
group of structures. On the contrary, some accumulations in the basal intervals of
eroded diapir folds (PK and KaS Formations in the Gyugryany-More and Zhiloy
Isl., KS and PK in the in the Balakhany-Sabunchi-Ramany fields) are in the zone
of mostly uneroded structures. It shows that the named hydrocarbon aggregations
formed under the general scheme of the accumulation formation and preserva-
tion in this group. The nature of this from the first sight anomalous phenomenon
relates to the specifics of hydrocarbon accumulations' formation mechanisms in
the basal and removed intervals of the Productive Sequence (reviewed later). On
the other hand, the noted facts indirectly show also that the chemical composi-
tion of water syngenetic with the Productive Sequence in different areas of the
Apsheron oil and gas region did not significantly vary prior to hydrocarbon accu-
mulation and changed subsequently according to the general mixing patterns of
different water types typical of the entire region (Rachinsky, 1970; Rachinsky and
Kuliyev, 1984).
