Transcript Use of source-to-sink concepts to provide insight to the stratigraphic record Tor O.

Use of source-to-sink concepts to provide
insight to the stratigraphic record
Tor O. Sømme1, Ole J. Martinsen2, William Helland-Hansen1, Ian Lunt2, David J.W. Piper3,
Mark E. Deptuck4, Christopher A-L Jackson5
1. Department of Earth Science (UIB), 2. Statoil, 3. Geological Survey of Canada (BIO)
4. Canada-Nova Scotia Offshore Petroleum Board, 5. Imperial College London
The source-to-sink concept
• Intermediate to long
timescales
• Ancient systems are
incomplete outside
subsiding basin
• Missing gaps are filled by data from modern
systems
• Segments are genetically related and firstorder characteristics should be time
independent
• Requires simplicity
Outline
Quaternary Golo system
- 103 year resolution
- All segments preserved
- Sediment budget, link between onshore
and offshore stratigraphy
Late Cretaceous Møre systems
-
106
5 km
year resolution
- Only basin floor and lower slope
preserved
- Paleo-drainage, sediment routing,
stratigraphy
?
?
Golo stratigraphy - short time scale
Lobe age
Old
Young
Thrust front
Sømme et al. 2011
• When is sediment being deposited within the different segments?
Alluvial terraces
60
Thrust front
50
N2
40
30
-
Ponte Leccia
N3
N4
N5
N6
70
Casamozza
20
10
0
60
50
40
30
20
10
Distance (km)
Hercynian domain
Alpine domain
Oldest
Youngest
0
Elevation above river (m)
70
Alluvial terraces
N3
N4
• Bedrock straths with alluvial cover
• Time equivalent with mass wasting from hill slopes
N5
N6
Marine deltas
Pluquet 2006
Deep-marine fans
Deptuck et al. 2008
Stratigraphic link between segments
Forest
vegetation
Sømme et al. 2011
Deep sea fan lobes
• Supply estimates
from the BQART
model (Syvitski &
Milliman, 2007) are
in good agreement
with calculated
volumes
Shelf units
Alluvial terraces
• Deposition in each
segment is
controlled by local
thresholds – hard to
fit into one model
Siddall et al. 2003
Estimated
sediment
from BQART
model
Steppe
vegetation
Brauer et al. 2007
Måløy Slope
Møre stratigraphy - long time scale
Sognefjorden
Modified from Jackson et al. 2008
• Late Cretaceous (Turonian), Northern North Sea
• Same scale as the Quaternary Golo system
Turonian fans
High
Amplitude
10 km
Low
?
N
?
?
?
Turonian onlap/truncation
• A total of 12 fan complexes have been mapped (12-298 km2)
• Fan spacing: 6-28 km
Generations of structures and topography
200 km
1st order: landscape and
drainage controlled by
“old” fault- and suture
zones - regional
2nd order: landscape and
drainage controlled by
long-lived, semi-regional
structures
3rd order: landscape and
drainage controlled by
relatively short-lived,
local structures
Generations of structures and topography
100 km
Øygarden Fault Complex
1st order preCaledonian
structures
2nd order postCaledonian
structures
Constraining paleo drainage
1,000,000
y = 4.8356x1.4428
R² = 0.6706
100,000
Catchment area (km2)
10,000
1,000
100
10
1
Turonian fan spacing: 6-28 km
0
0.1
10000000
10
100
Catchment spacing (km)
100000
10000
1000
100
10
Turonian fan areas: 12-298 km2
1
1
100
1000
• Use relationships between
catchment area, outlet
spacing and extent of fan
complexes from modern
systems to constrain paleocatchments
y = 16.386x0.8455
R2 = 0.8091
1000000
Catchment area (km2)
1
10000
Fan area (km2)
1000000
• Suggest paleo source areas
of ~100 – 2000 km2
Constraining paleo drainage
Estimated catchment area (km2)
11000
South
10000
North
Fom Fan area
9000
From catchment
spacing
8000
7000
6000
5000
4000
3000
2000
1000
0
0
1
2
3
4
5
6
7
8
9
10
11
12
Fan-catchment number
• Independent estimates of paleo catchments suggest ~100 to ~2000 km2
• Estimates overlap within the uncertainties of one standard deviation
Depositional model
• Source constrained to local fault blocks
• Coarse and immature sediments
• Short transport routes
• Little internal filtering/buffering
Fans architecture
High
N
10 km
Low
Selje High
Lithology and stratigraphy
top Turonain
intra Turonian
Lithology and stratigraphy
top Turonain
intra Turonian
Implications for reservoirs
High
10 km
Low
?
N
?
?
?
Turonian onlap/truncation
• Implications for intra fan and regional sandstone connectivity
• Implications for lithology and reservoir quality
Summary and conclusions
• The ultimate goal is a predictive tool that can
constrain morphology and stratigraphy in
ancient subsurface systems
• Model is populated with empirical data from
modern systems
• Requires simplicity
5 km
• The Quaternary Golo system suggests that
sediment storage in segments is linked to local
thresholds
• We can estimate the morphological and
sedimentological characteristics of the Late
Cretaceous Møre systems based on modern
data
?
?