Geology Reference
In-Depth Information
2. Hydrochemical field of Alpine fold belt regions is clearly
mosaic and distinct in its substantial space-time variability.
It reflects the step-block structure of the sediment cover. It
forms under the dominating effect of powerful interforma-
tional fluid cross-flows. These cross-flows are synchronous
with periods of tectonic activity and neotectonic phases and
form through mixing in different proportions of ground
waters of different stratigraphic belonging.
3. Geobaric field of the Alpine regions is highly stressed.
Almost omnipresent are abnormally high pore and forma-
tion pressures polygenic in nature. They commonly form
in reservoirs on local structures through vertical penetra-
tion of high-pressure fluids and geotectonic compression
of closely-elastic natural reservoirs. These fluids invade
isolated volumes from the basal horizons of the sedi-
ment cover. They form in thick clay sequences mostly as
a result of their lithostatic and tectonic compaction with
the restricted outflow of the pore fluids. They also emerge
due to dehydration-caused catagenesis accompanied by the
release of additional interstitial (bound) water as the free
phase. They form in clay barriers above hydrocarbon accu-
mulations due to the halo-shaped penetration of those flu-
ids under excess pressure.
4. Thick subsiding clay sequences sequentially go in their
geologic evolution through the stages of the flow compac-
tion and diffusion compaction and of catagenic dehydra-
tion decompaction. The model we developed allows the
operation of geo-hydrodynamic systems under the elision
scheme, most likely only at the flow compaction stage.
5. Spatial distribution of the formation and pore pressure
abnormality factors, the direction and implementation
extent of their gradients (in consideration of all other con-
ditions of necessity and sufficiency) trace the migration
of natural fluids and can be used as forecast criteria of the
hydrocarbon saturation and for evaluating it qualitatively
and quantitatively.
6. Cumulative relaxation of the elastic energy in thick non-
uniformly-compacted low-density elastoplastic clay series
with AHPP is a significant factor in the formation of
regional and local folding, fault dislocations, overthrust
and nappe tectonics, in the structural relationships between
