Geology Reference
In-Depth Information
Koelbl, 1967; Krejci-Graf, Hecht and Pasler, 1957). Commercial oil occur-
rences in the formation in some fault-blocks of Matzen and Aderklaa fields
and Prottes-Tief, Brittenlee and Schonkirchen-Uber Tief prospects and
water shows on a number of other structures are associated with chlorine-
calcium waters of elevated salinity (140
−
310 mg.-equiv. or 40
−
90 g/l) with
secondary salinity factor 15
20%-equiv.
From the
Lower-Middle Miocene
sediments (Burdigalian and Helvetian
Stages) ground waters were obtained at the Matzen, Aderklaa, Sankt-
Ulrich-Hauskirchen, Pioneer-Kreizfeld, Meistrenk-Scharfenek, Paasdorf,
Platzwald and Schonkirchen-Tief fields/prospects.
Dominating
in the pro-
ductive areas of the structures are chlorine-calcium waters with 35.3
−
−
105.7
mg.-equiv. salinity (10.1
13.4%-
equiv. The waters that belong to the hydrocarbonate-sodium type (salinity
31.9
−
30.2 g/l) and secondary salinity factor 9
−
9.4%-
equiv.) serve as hydrochemical background. They are encountered in the
nonproductive fault-blocks of the Aderklaa, Matzen and Sankt-Ulrich-
Hauskirchen fields. Zones of commercial oil correspond with hardest and
highest salinity waters.
Ground water flows from the
Middle-Upper Miocene
sediments
(Tortonian and Sarmatian Stages) are produced practically at all prospects
of the region. The background is formed by hydrocarbonate-sodium variet-
ies with salinity 26
−
52.6 mg.-equiv. or 9.1
−
15 g/l, primary alkalinity factor 6.6
−
−
50 mg.-equiv. (7.5
−
14.3 g/l) and primary alkalinity fac-
tor 25
46%-equiv. Commercial oil occurrences in the Aderklaa, Matzen,
Hesting, Heizelberg, Zwerndorf, Sankt-Ulrich-Hauskirchen and other
fields/prospects is encountered against the hydrochemical background of
low-hardness and least alkaline waters with elevated salinity (44
−
−
100 mg.-
equiv. or 12.8
28.6 g/l).
he
Pliocene
(Pannonian Stage) is almost everywhere saturated with
highly alkaline waters (primary alkalinity factor 35
−
−
70%-equiv.) of low
salinity (to 10
4.3
g/l) (the Muhlberg, Heizelberg,
Hesting, Pioneer-Kreizfeld, Van-Zikl, Sankt-Ulrich-Hauskirchen and
Hodonin fields/prospects). These waters serve as the hydrochemical back-
ground. Maximum salinity and minimum alkalinity values belong to the
productive intervals.
An independent group of ground waters in the region is the waters
encountered in the uppermost (near-surface) section (shallower than about
200
−
15 mg.-equiv. or 2.9
−
0.54 g/l)
sulphate-sodium waters of clearly infiltration (meteoric) origin. They
have high secondary alkalinity factor values: 75
−
300 m). These are low salinity (1.3
−
2.0 mg.-equiv. or 0.37
−
89%-equiv. Their effect
on the hydrochemical environment of deeper intervals is usually low. It is
limited to the reservoir members adjacent to the surface exposures. There,
−
