Well 5 Well 2 Well 3 Well 4 Well 1
Vail et al., 1977b
AAPG©1977 reprinted with permission of the AAPG
whose permission is required for further use.
Vail et al., 1977b
AAPG©1977 reprinted with permission of the AAPG
whose permission is required for further use.
Well 5 Well 2 Well 3 Well 4 Well 1
A B
C
D
E
F
A
B
C
D
E
F
G
A
B
C
D
E
F
G
A B
C
D
E
F
H
Vail et al., 1977b
AAPG©1977 reprinted with permission of the AAPG
whose permission is required for further use.
Well 5 Well 2 Well 3 Well 4 Well 1
Reservoir rock
Seal
Migration route
Oil/water contact (OWC)
Hydrocarbon accumulation
in the reservoir rock
Top of maturity
Source rock
Fault (impermeable)
6
Plate Boundaries Divergent
Convergent
Transform
Structural Environments Extensional
Compressional
Strike-slip
Passive (Salt)
9
BASEMENT
INVOLVED
BASEMENT
DETACHED
EXTENSION COMPRESSION LATERAL UPLIFT,
SUBSIDENCE
extensional
fault
blocks
detached
normal
faulting
contractional
fault
blocks
fold-and-
thrust belts
strike-slip
or wrench
faulting
tear faults
(detached)
basement
warps
salt, shale
diapirism
10
Structural Hydrocarbon Traps
Salt Diapir
Oil/Water Contact
Gas Oil/Gas Contact
Oil
Closure Oil Shale Trap
Fracture Basement
(modified from Bjorlykke, 1989)
Fold Trap
Oil
Salt
Dome
11
Structural Observations
• Fault segments on seismic lines • Fault plane orientation • Sense of motion • Magnitude of offset • Range of depths • Relative timing
– when faults moved – when structures grew
Structural Concepts
• Tectonic Setting – Divergent zones – Convergent zones – Strike-slip zones – Mobile substrate
• How Structures Evolve – Fault-bend folds – Fault-propagation folds – Salt movement – etc.
13
3D Structural Closure, Cooper Basin (Australia)
Merrimelia Fm: - Starts the Cooper Basin - Waxing and waning of glacial sediments
Cooper Basin
Triassic
Triassic Inerval
Perm
ian
Toolachee Fm
Roseneath Shale
Epsilon Fm
Murteree
Fm
Patchawarra
Tirrawarra Fm
Carb
onife
rous
Merrimelia Fm
15
Salt and shale layers can become mobile
when subjected to differential loading
Many oil and gas fields have been found
associated with salt & shale diapirs
Imaging beneath salt is very difficult, but the rewards can be great!
16
28
Seismic section from the JDZ between Nigeria and Sao Tome/Principe. The blue lines indicate thrust faults. PGS
Depositional Channels Bars Pinch outs Reefs
Unconformity Traps Above Unconformity
Onlap Valley Fill Channels
Diagenetic Traps Permeability Barriers
31
Stratigraphic Observations
• Seismic Terminations Base of Sequence Top of Sequence
• Lateral Geometry – Map View Channel Pinch Out Reef
•Relative timing
Stratigraphic Concepts
• Environment of Deposition – Fluvial – Shallow Marine – Deep Marine
• Carbonate or Terrigenous
33
Oil/Gas
Oil/Gas
Oil/Gas
Stratigraphic Hydrocarbon Traps
Uncomformity
Channel Pinch Out
(modified from Bjorlykke, 1989)
Unconformity Pinch out
34
Younger Beds
Younger Beds
Erosion Toplap
A top-discordant relationship in
which strata terminate along an
unconformity surface due to
post-depositional erosion
A top-discordant relationship in
which strata terminate against a
surface mainly as a result of
non-deposition (bypass)
36
Courtesy of ExxonMobil
Older Beds
Onlap
Older Beds
Downlap
A base-discordant relationship
in which younger strata
terminate progressively against
a surface of greater inclination
A base-discordant relationship
in which younger inclined strata
terminate progressively against
a surface of lower inclination
37
Deep water slope
Continued regional
subsidence
Interbedded shale and
sandstone
Submarine fan and
turbidite deposits
Tertiary
NW SE
39
3D seismic slice- Fluvial meander at ~2.3 seconds in the West Natuna Basin, Indonesia. ConocoPhillips, Indonesia
43
Recoverable Reserves: Oil : 10 billion bbls Condensate : 1.3 billion bbls
Reservoir: Turbidite sands in a major Eocene submarine canyon
Reservoir Thickness 200 to 500 meters
Discovered while drilling for deeper Cretaceous limestone.
10% recovery factor
47
Asphalt Trap
Water
Meteoric Water
Biodegraded Oil/Asphalt
Partly Biodegraded Oil
Hydrodynamic Trap
Shale
Oil Water
Hydrostatic Head
(modified from Bjorlykke, 1989)
Other Traps
56
Traps Structural
Stratigraphic
Combination
Other
Unconformities are Important Traps Above – Valley Fill or Onlap
Traps Below - Truncation
61
62
Assignments
Complete All Homework
Discuss Current Energy Events Read Today in Energy for Thursday (4/2) at
http://www.eia.gov/
Be Prepared to Discuss in Class – Monday (4/6)
Discussion Leader – Alexander Ekvall
Test – Wednesday – April 8 Material Through Monday (4/6) will be on Test
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