Geology Reference
In-Depth Information
geo-fluid-dynamical attributes, not only of the oil and gas presence but
also for well-substantiated judgment of possible accumulation types and
their reserve amounts.
In previous sections, we provided a theoretical justification for the use of
geo-fluid-dynamical attributes in the South Caspian Depression. This justi-
fication is the concept of the hydrocarbon saturation in its Meso-Cenozoic
reservoirs due to the invasion of low-salinity alkaline waters from the deep
sedimentary section. These waters are foreign to the enclosing sediments
and transport hydrocarbons. Another major position for the applicability
of geo-fluid-dynamical attributes of oil and gas occurrence is the proven
association between the types of hydrocarbon aggregations and dynamics,
chemistry and component composition of ground waters in contact with
these aggregations.
It is believed, based on studies, that one major geo-fluid-dynamical fac-
tor determines the possibility for the formation of accumulations, fields and
regional hydrocarbon saturation zones. This factor is geologic conditions
and mechanisms facilitating the injection of reservoirs with foreign hydro-
carbonate-sodium waters transporting hydrocarbons. Thus, these condi-
tions facilitate the emigration of the section-syngenetic ground waters. In
other words, aggregation of hydrocarbons into commercial accumulations
may occur only in a geologic environment conducive to the discharge of a
geo-fluid-dynamical system.
The general preconditions for discovering hydrocarbon saturation are:
t
The presence of depth hydrocarbonate-sodium waters' dis-
charge zones.
t
The presence within the same structure of several water
types of various salinity. For large oil aggregations, broad
occurrence of low-salinity alkaline waters is necessary.
t
The presence on local structures of low-salinity hydrocar-
bonate-sodium water spots against the general background
of chlorine-calcium brines.
t
The existence of epigenetic AHPP within clay seals above the
accumulations (“invasion halos”).
The connection between hydrochemistry (ground water type and
salinity) and oil and gas occurrences in the Middle Pliocene Productive
Sequence of the region is clear from the following examples. In the fields
Balakhany-Sabunchi-Ramany, Surakhany, Karachukhur, Zykh, Peschany
Isl., Zyrya, Lokbatan, Neftyanye Kamni (“Oil Rocks”), Yuzhnaya and
others, a clear association is recorded between depths of the boundaries
