Part 1 Basin, Structures, Traps and Plays
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Transcript of Part 1 Basin, Structures, Traps and Plays
Petroleum Geoscience
EAB -7- 151
Basin, structures and traps
Dr. Julie D. Bell RPG, PhD
What is a sedimentary basin?A sedimentary basin is a depression filled with
sedimentary rocks.
Areas of basins can be 1 to 10 km plus
• A sedimentary basin is
– a depression filled with sedimentary rocks
– formed by any tectonic process
– filled with sediments, organics and water
– elements necessary to create a petroleum system are put in place
– traps are formed by tectonic processes.
• Reservoir models are made of the particular parts of basin that the company has located a play.
Classification of sedimentary basins
Sedimentary basins can be classified according to
structural genesis (or how they were developed)
evolutionary history (that can be linked to petroleum systems and play development)
• The foundations of sedimentary basins
• The mechanics of sedimentary basin formation
The foundations of sedimentary basins
Read Basin Analysis Principles and Applications Philip A. Allen
and John A. Allen page 3-- 218
Petroleum geologist - basin modelling
• At its most basic, a basin modelling exercise must include:
– burial history
– thermal history of the basin
– maturity history of the source rocks.
– expulsion, migration and trapping of hydrocarbons
Basin evolution
Number and variety of plays increases with basin evolution, as tectonics and sedimentary patterns become more complicated.
Different basin cycles can be present pre-rift
syn-rift
Transitional
Post-rift
Same or different petroleum systems can be present due to changes in cycles
How to understand evolution?
• Determine history of the basin fill including
– composition,
– primary structures, and
– internal architecture, can be synthesized into a model of stages of development, or a basin model
• Sedimentary basins are regions of prolonged subsidence of the Earth. The driving mechanisms of subsidence are principally driven by processes in the lithosphere. The earth consists of different zones.
Geometries in a basin
Geometries in sedimentary basins
Applied study for petroleum not academic, petroleum traps
Structural geology - study of 3D distribution of rock units with respect to their deformational histories
Planar features ○ bedding planes
○ foliation planes
○ fault planes
○ fold axial planes
Other features ○ joints
○ Stretching
Structures are present on all scale from macro to micro
Bedding planes - normal bedding
Bedding planes - folded beds
Fault planes
Bedding and normal and fold planes
Fold axial planes - Anticline
strike
plunge
Strike – the
direction that
the beds are
facing ie. NE
Plunge – the
angle that the
beds are from
the ground
surface ie 45
Fold axial planes - Synclines
Traps
Traps
Read Petroleum Geosciences Gluyas and Swarbrick Section 4.5 p 148-169
• Structural traps (fig 4.36 p149)
• Stratigraphic (fig 4.37 p150)
• Evaporites and salt domes (fig 4.47 p160)
Formation of traps and timing are critical
Structural traps
Read Petroleum Geosciences Gluyas and Swarbrick Section 4.5.3 p 151-163
What are the 6 types?
Salt dome traps
What are the 8 parts?
Wytch field is a synclinal fault basin with a
stratigraphic pinchout trap