Geology Reference
In-Depth Information
the abnormality factors reach 1.46 (see Figure 3.1). At the Uzun-Ade pros-
pect in the Kyzylkum Trough at MD=3,750 m the abnormality factor is
1.17. In the Kotur-Tepe Field on the flank of the previous one the same
Red-Bed intervals at MD=2,500 and 1,500 m have the abnormality factor
of 1.22-1.33 (Shuvalov, 1977). The described distribution uniquely indi-
cates the impossibility of lateral ground water flow in these areas from the
central more subsided portion of the South Caspian Depression to its flank
framework.
AHFP distribution in the Los Angeles depression is similar. Maximum
values of the abnormality factor (1.26) in the Neogene complex are
recorded in the Torrance-Wilmington zone fields up the regional dip.
Minimum values are found in the Englewood-Newport anticlinal belt and
in the fields Santa Fe Springs, Boudini and West Coyote located closer to
the central subsided portion of the basin (see Figure 3.6). Elements of a
similar distribution are observed in the Neogene of the Padan Depression.
In the Caviaga Field the abnormality factor reaches 1.8-2.1. The same
interval in the Cortemaggiore Field 1,000 m down the regional dip its
maximum value does not exceed 1.43 (Figure 3.3). In the Maracaibo
Depression the Oligocene-Paleocene on the relatively uplifted West flank
structures (La Conception, Mapa and La Paz) have the factors on the
order of 1.22. The abnormality factors on the structures in the subsided
axial part of the basin (Bolivar, Mene-Grande and other zones) does not
exceed 1.10 (see Figure 3.7).
Even more contrasting is the situation in the Alpine piedmont troughs.
In the Internal zone of the Carpathian Trough in the Cretaceous-
Oligocene flysh, the highest abnormality values are observed on the struc-
tures of the uplifted Borislav-Pokut anticlinorium. Maximum factors in
the Eocene-Miocene of the Indolo-Kuban Trough are recorded in the
fields adjacent to its south flank (Zybza-Gluboky Yar, Abino-Ukrainskoye,
Akhtyr-Bugundyr, Kurchan, West-Anastasiyev, etc.). The rest of the terri-
tory including the axial zone has formation pressure close to the hydro-
static (Slavyansk, Abkhaz, Krasnodar and other prospects) (Figures 3.9,
3.10) (Durmishyan, Muradian and Rachinsky1 1976; Kissin, 1964). In the
Cretaceous and Miocene of the Tersk-Caspian Trough, the abnormality
noticeably increases from the trough's centroclinal toward the relatively
uplifted platform slope. Maximum abnormality factor values are found in
the fields of the so-called “zone of the accompanying folding” in the Tersk
anticlinorium and Terek anticlinal belt (see Figure 3.11). In the Bangestan-
Asmari (Upper Cretaceous-Lower Miocene) reservoir of the Zagros
Trough, in the offshore fields located closer to its central zone (Nowruz,
Bahregansar and Hendijan) the normalized pressures are lower compared
