Geology Reference
In-Depth Information
0
10
20
30
40
50
60
70
80
90
100
110
120
P
res
, MPa
500
Miocene
1000
1500
2000
2500
Oligocene
Eocene
Paleocene
Up. Cretaceous
L. Cretaceous
3000
3500
4000
4500
5000
5500
6000
H
,
M
Figure 3.7
Initial formation pressure in waterhead complexes of Maracaibo Basin. Fields:
1.
Lamar,
2.
La Paz,
3.
La Concepcion,
4.
Mene Grande,
5.
Boscan,
6.
Los Carlos,
7.
Urdanetta,
8.
Mara,
9.
Lama,
10.
Sibucara,
11.
El Rosario,
12.
Tibu.
total clay content of the section and by silting of the lens-shaped reservoir
members in the said formations.
In this connection it is possible that these most clayey complexes were
maximally affected by neotectonic effects. They caused additional elas-
tic compression of reservoir beds and their saturating fluids. The role
and value of these mechanisms is objectively reflected in the correlation
(Figure 3.8) of average abnormality factor value vs. ratio of impermeable
(low-permeability) to permeable rocks in the sedimentary section (
С
, %
impermeable varieties in the total thickness of the sedimentary sequence).
A direct correlation exists between both variables. It supports the increas-
ing significance of fraction of syngenetic abnormal pressure generation
mechanisms in the total AHPP with increasing “
С
” parameter value.
3.2.2 Foredeeps
3.2.2.1
The Carpathian Foredeep
AHPP in the sequence of Miocene molasses' plastic clays was established
all over the trough territory, and AHFP in the reservoirs of the Upper
Cretaceous-Miocene section, in the Internal zone (Table 3.5, Figure 3.9).
