THE HABITAT OF HYDROCARBONS IN SEDIMENTARY BASINS (cơ sở KHOA học địa CHẤT dầu KHÍ SLIDE TIẾNG ANH)
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Chapter 08:
THE HABITAT OF
HYDROCARBONS IN
SEDIMENTARY BASINS
Content
Introduction
8.1-The Sedimentary Basin Concept
8.2-Sedimentary Basin Classification
8.3-Distribution of petroleum – rich
basins
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Introduction
There are approximately 600 sedimentary
rock basins in the world.
A quarter of them are producing petroleum
Before exploitating in a new area, attemting
to locate drillabe prospects, it is necessery to
establish the type of basin, what productive
horizons it may contain and where they
may be broadly located
3
• Even though petroleum reserves can be
found in rocks of all ages, most giant fields
and most of the world's reserves occur in
sequences, of Late Mesozoic and Cenozoic
age ( Figure 01) . Paleozoic rocks probably
had potential to generate hydrocarbons
equal to that of these younger rocks, but
there has been more time in which to
destroy all or part of the petroleum through
uplift and erosion (Halbouty et al, 1970).
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Fig: 01
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• Worldwide reserves can be related to their location within
a petroleum basin, regardless of its basin type (Figure: 02)
Fig: 02
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8.1-The Sedimentary Basin Concept
• A general term for any large area of tectonic
origin with a thick accumulation of
sedimentary rocks.
• A basin is a geological structure with a
unique sequence of rocks that are dissimilar
to those outside the basin.
• A low area with no exterior drainage.
• Include both depression itself and the thickerthan-everage sediments that fill it
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Fig: 03
Idealized pattern of a sedimentary basin
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Fig: 04
Sedimentation patterns over arch, shelf and basin
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Main content:
1.Geometry of Sedimentary Basins
2.Sediment Fill
3.Tectonic Processes and Timing
4.Basin-Forming Mechanisms
5.Sedimentary Basin Classification
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Geometry of Sedimentary
Basins
It is tempting to believe that a
sedimentary basin was deepest where
its sediments are thickest, but this is
not necessarily true
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Fig: 05
Non-coincidence of depocenters, topographic low and point of maximum
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basement subsidence in a land-derived, prograding clastic wedge
Sediment Fill
Basins can be characterized by the sediments
that fill them.
They can be dominated by continental,
shallow marine, or deep marine sediments,
depending on their elevation and the
interplay between the rate of subsidence
and the rate of sedimentation
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Tectonic Processes and
Timing
• An important aspect of sedimentary basins
is the nature and timing of tectonic
processes.
• The types of folds and faults that develop
within a basin are partly due to
deformation mechanisms and partly to its
sediments
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Basin-Forming
Mechanisms
• Basins form as a result of large-scale
vertical and horizontal movements within
the earth's upper layers (fig. 06-1) , which
can be explained through the widely
accepted theory of plate tectonics.
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Fig: 06-1
• The earth's outermost shell is a rigid
layer called the lithosphere, which
consists of crust and uppermost mantle.
Topographic lows form on the earth's
surface where the crust is thin, and
composed of dense basaltic rocks
• The rigid lithosphere overlies a less
viscous layer called the asthenosphere
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Fig: 06-2
The earth's outermost layers
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Fig: 07
Distribution of lithospheric plates, showing relative velocity
and direction of plate separation and convergence in
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centimeters per year
Initiation of rifting and ocean floor
spreading over continental crus
Fig: 08
Pre-rift domal bulge
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Fig: 09
Initial radial rift
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Fig: 10
Early separation stage
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MODEL OF A DIVERGING PLATE BOUNDARY
Fig: 12
The separated continents are now far apart, and basins develop along their
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passive margins
MODEL OF SUBDUCTING PLATE MARGIN
Fig: 12
At a subduction zone, the leading edge of one plate overrides another, and the
overridden plate is dragged down into the mantle and consumed
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MODEL OF A COLLISIONAL PLATE MARGIN, SHOWING
COLLISION BETWEEN OCEAN PLATE AND A CONTINENTAL
MARGIN
Fig: 13
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