Geology Reference
In-Depth Information
chlorine-calcium, chlorine-magnesium, sulphate-sodium
and hydrocarbonate-sodium higher salinity varieties against
the freshened high-alkaline regional background.
t
Their continuous localization in the most faulted areas of the
productive structures.
t
Fitting genetic outlook of the said formation solutions with
the process of mixing in various proportions of the lower
high-salinity chlorine-calcium water with syngenetic low-
salinity hydrocarbonate-sodium water (Chapter 2).
t
Spatial association of the positive concentration, component
composition, geothermal and negative piezometric anoma-
lies (Chapters 3, 4) with the areas of high faulting and maxi-
mum oil-saturation (Chapter 6).
The commonality of vertical fluid migration in the region is also sup-
ported by petroleum geology data, in particular:
t
Stacked nature of the fields.
t
Commercial hydrocarbon accumulations in the entire sedi-
mentary section from the basement (Wilmington, Long
Beach, Playa del Rey, El Segundo and other fields) through
the Pleistocene (Yorba Linda field) (Bakirov, 1959; Barbat,
1961; Reference book…, 1976).
t
Clear control of oil and gas occurrences by faults (Rachinsky,
1987, 1989) and the geochemical outlook of the oils
(Levorsen, 1970; Hunt, 1982; Philippi, 1974).
5.2.1.6
The Maracaibo Depression
The published concepts of regional hydrodynamics of the sedimentary
sequence give preference to the infiltration model. Under this model
the basin-fringing Andean spurs Sierra de Perija, east Cordillera, Andes
Merida are the meteoric charge source of the water complexes, whereas
the discharge zone is Lake Maracaibo. It was shown, however, that the
water-exchange mechanism proposed by these authors, albeit intended to
cover plenty of the section and of the area, is based on limited, narrowly-
local actual data involving mostly the Piedmont zone, some (primarily
upper) intervals of the sediment cover, a few accumulations, fields, struc-
tures and even their parts, fault-blocks and areas. Naturally, these do not
support the reliability of the postulated model. For instance, as a proof of
the large-scale present-day infiltration in the basin, hydrochemical data
