Geology Reference
In-Depth Information
Nikanorov, Volobuyev and Bartsev, 1975; Nikanorov and Miroshnikov,
1970).
The following fact is important. The Karaganian and Chokrackian depos-
its in Oktyabrsk and Starogroznensk fields with maximum for the region
reserves density in these intervals also contain the highest salinity and
hardness waters compared with other fields where the oil-saturation of the
reservoirs and their productivity is lower. Another noteworthy fact is that
in all cases of accumulations associated with the Tertiary complexes and
their consistent and mandatory association with positive hydrochemical
anomalies there is one more precondition for the commercial oil produc-
tivity of the Neogene stage. This precondition is large hydrocarbon aggre-
gations in the underlying Mesozoic. In other words, the Neogene intervals
are oil-saturated only on the structures with large commercial oil reserves
in the Cretaceous and Jurassic. At the same time, the “dry” Mesozoic struc-
tures usually do not include oil accumulations in the Tertiary deposits.
The described patterns have been reported in all basins of Alpine mobile
belts regardless of their geographic position, geotectonic belonging, litho-
facies type of the sections, stratigraphic age, amount of the sedimentary
fill and other specific features. This determined the unique and manda-
tory nature of their forming mechanism, i.e., vertical inter-formational
fluid migration from deep areas of the section into the upper accumulating
natural reservoirs.
8.2
Quantitative Parameters in Correlation Between
Tectonic Features of Local Structures, Ground
Water Dynamics and Oil and Gas Occurrences
Previous sections have shown that migration in the productive traps and
accumulation processes in the Alpine mobile belt regions are mostly con-
trolled by dynamic conditions, influx and discharge balance from the sec-
tion of ground water and accompanying hydrocarbons (generated by the
source rocks in the lower intervals of the sediment cover) through faults,
elevated fracturing zones, hydrogeological “windows”, etc.
The quoted data enabled identification of the main factor determin-
ing and controlling geo-fluid-dynamic environment of local structures
and regional oil and gas accumulation zones, therefore, the conditions of
hydrocarbon accumulation and formation of commercial accumulations.
This factor is the nature of a region's deformation as a whole and the extent
of faulting in the individual natural reservoirs (traps, structures). At the
