Geology Reference
In-Depth Information
3. The main formation mechanism of a geo-fluid-dynamic
regime in the sediment fill of Alpine mobile belt regions is
vertical fluid-mass transfer from the lower into the section
upper intervals. This transfer is controlled by permeability
of the conducting paths, possibility of and degree of dis-
charge of the waterhead system. Active drainage of natural
reservoirs does not provide for the preservation of AHFP
and results in the development in reservoirs of the hydro-
static environment.
4. Alpine intermontane troughs have substantially less
stressed regional geo-fluid-dynamic systems. Average value
of the abnormality factor there is 1.33 compared with 1.55
for the foredeep troughs where it is equal to 1.55. An Alpine
mobile belt has average value of this parameter of 1.44.
5. Within local structures of the Alpine regions the waterhead
complexes of the entire sediment cover and in some cases
even basement (Maracaibo and Los Angeles depressions)
commonly have abnormally high formation pressure con-
tinuously increasing in its intensity with depth.
6. In all regions, AHFP manifestations in reservoirs are
recorded mostly on local highs. There, distribution of their
intensity over the area is clearly mosaic and subordinated to
the fault-block reservoir structure and conditions of their
discharge. Inter-structural zones and areas most commonly
display hydraulic environment approaching the hydrostatic.
7.
AHFP distribution over the regions demonstrates its man-
datory association with areas of inversely-uplifted neo-
tectonically active flank frameworks of depressions and
troughs, and positioned in the areas of intersection of large
deep-seated faults.
8.
On hydraulically open local structures absolute values of
formation pressure excess over the hydrostatic and of its
abnormality factor continuously decrease up the strati-
graphic section. Their maximum values are recorded
in natural reservoirs of the basal intervals in the drilled
sedimentary section. On hydraulically-closed structures
maximum values of said parameters are recorded directly
underneath the hydraulic seal.
9.
In all regions, AHFP manifestation intensity over the area
inversely correlates with the extent of faulting. Maximum
formation pressure abnormality values in reservoirs are
