Geology Reference
In-Depth Information
the elevation of hydrocarbon accumulations (the difference
in specific gravity of oil, gas and water; in the South Caspian
Depression fields, in the Lower Kura and Dzheiranchekmes
Depressions and in the Zagros Trough (Rachinsky, 1989)).
t
Spatial coincidence between AHFP areas and active mud vol-
cano activity (Indolo-Kuban Trough - Kerch-Taman zone,
South Caspian and Irrawaddy-Andaman Depressions).
t
Common development in the Alpine regions of tempera-
ture, hydrochemical, piezometric, isotope, palynologycal
and other anomalies.
Thus, manifestations of abnormally high formation pressure should be
considered to be local distortions of the fluid-dynamic environment in the
waterhead complexes that enable estimation of the regional potentiometric
background, hence, establishing the prevailing direction of fluid migration.
We will review the substantial importance of vertical discharge in the
formation of fluid-dynamic regime of the deep subsurface in the Alpine
mobile belt regions using the data from individual areas. We will con-
duct analysis of the areal formation pressure abnormality factor distribu-
tion as a function of local structures closeness to most subsided zones in
intermontane and piedmont troughs. In the view of some scientists, these
troughs are energy sources (charge areas) for functioning of the elision
fluid-dynamic systems. Apparently, a consistent decline of these factors
up the regional dip should be interpreted as an indication of potential
implementation of the elision-lateral water-exchange. The inverse pattern
indicates its absence and therefore the likelihood of the alternative (mostly
vertical) mass transfer model.
Actual data for the South Caspian Depression show that the water-
head gradient distribution over its individual areas does not match the
elision model. A similar picture is observed for instance in the Apsheron
Archipelago. There, in the Kala Fm. (KaS) of the Yuzhnoye Field at 4,200 m
depth formation pressure is hydrostatic. At the same time in the Zhiloy Isl.
Field (5 km up the regional dip within the same anticlinal zone) formation
pressure excess over the hydrostatic within the same interval at MD 1,600
m is 5 MPa with the abnormality factor of 1.31.
The same is recorded on the east flank of the depression. There,
in the Upper Red-Bed of the Ogurchin and West-Erdekli prospects
located in the subsided offshore zone, formation pressure matches the
hydrostatic. In the same horizons in the adjacent fields of the Balkhan
and Gograndag-Chikishlyar zones of highs (Cheleken, Barsa-Gelmes,
Gograndag, Chikishlyar and some others) positioned up the regional dip
