Geology Reference
In-Depth Information
Figure 8.11
Reserves density and per-unit reserves volume vs. average formation
pressure abnormality factor by the region. ЮКв - South Caspian Depression, Пв - Padan
Depression, Вв - Viennese Depression, ИрАв - Irrawaddy-Andaman depression, Мв -
Maracaibo Depression, Лав - Los Angelesская depression, ИКп - Indolo-Kuban Trough,
ТКи - Tersk-Caspian Trough, Пзп - Zagros Trough.
of the natural reservoir. That resulted in the formation of high thermal
gradient piezo-maximums underneath the water barrier of the overthrust
nature.
Organizing the quoted materials also reveals that the fields in all Alpine
regions are stacked (multi-zone) and within the range of geothermal gradi-
ents and formation pressure abnormality factors optimal for the formation
and preservation of hydrocarbon accumulations. And the depth range of
oil and gas occurrences in them is the highest.
Within the range of minimum thermal gradient and
К
ан
values (corre-
sponding with the destruction environment of hydrocarbon aggregations),
preserved fields often lack accumulations of the upper section intervals
due to their degradation and wash-off by ground waters invaded from the
lower horizons of the sediment section. Within the range of maximum val-
ues (corresponding with the environment of the absence or limited hydro-
carbon accumulation), the formed aggregations are mostly single-layered
or with only a few reservoirs and with low depth range of the saturation
(Figures 8.7, 8.10).
The diagnostic attribute of the first type is a mosaic spatial distribution
of ground water salinity, component composition and type in combina-
tion with large-scale oil- and gas-saturation. The diagnostic attribute of
the second type is ubiquitous development in the basal horizons and com-
monality in the upper intervals of field sections of high-pressure, high-
temperature, lower saline, hard or desalinated alkaline waters conjoined
with residual productivity of the shallowest intervals. The diagnostic attri-
bute of the third type is complete or substantial preservation in a natural
