Transcript Salt Canopy - UTEP Geological Sciences

Salt Canopy
•Allochthonous salt sheets are
abundant in the deep water of GoM
on passive margins. Then, these salt
sheets commonly merge, forming a
“Salt Canopy”.
•It may reach thicknesses of 20,000
ft.
•Its intrusion in the surrounding rock
creates problems for every step of
the exploration, drilling, completion
and production.
•The study area is multilevel salt
system consisting of a series of
allochthonous, rootless salt
bodies and salt welds
http://peakwatch.typepad.com/photos/research_images/walker_ridge_salt_canopy.jpg
Evolution of salt stocks
and how it influenced
petroleum migration
pathways
• Petroleum migration is believed to
be vertical until it reaches the base
of salt, at which point it is deflected
up the dip along the base of salt.
• The evolutions are related to
Cenozoic basin developments.
Changes in length of suprasalt
section show amounts of extension
and contraction.
•
Many of the zones of subsalt petroleum
migration concentration no longer exist
because of the dynamic evolution of salt
•
Major reservoir rock is Neogene siliciclastic
turbidite systems.
•
These sediments were deposited within bathyal
water depths in intraslope basins controlled
primarily by active salt tectonics.
•
Geologic facies show abrupt variations both
laterally and temporally as a function of the
structural controls on sediment pathways across
the slope, and the positioning of shallow marine
depocenters.
•
Most of the reservoirs occur within Pliocene and
lower Pleistocene sands deposited in a variety of
environments.
•
The sediments are generally all fine grained with
differences in geometries and rock types among
these turbidite systems.
Oligocene- Miocene-Pliocene
Reservoir Rocks