Clastic Sequence Stratigraphy and Sedimentation
Evert van de Graaff
Mark Bouman
5 days
Business context
A good understanding of how depositional processes control
the distribution of clastic reservoir and non-reservoir rocks in
the subsurface is of fundamental importance to sound EP decision
making. This applies throughout a field's life-cycle, all the way
from the exploration phase, through appraisal, field development
and finally field abandonment.
Who should attend
Petroleum geoscientists. petroleum engineers and
members of integrated asset teams, who are responsible for defining
and evaluating subsurface geological risks and uncertainties. The
course targets EP professionals in the initial phase of their
career.
Course content
Overview of clastic stratigraphic analysis and
sequence stratigraphy. Course focuses on how geological
characteristics of a reservoir impact on EP decision making during
all phases of a field's life cycle.
- Clastic depositional systems &reservoir
characteristics
-
- Fluviatile systems
- Deltaic systems
- Non-deltaic coastal systems
- Deepwater ("turbidite") systems
- Sequence stratigraphy
-
- Controls on sea level
changes
- Fundamental concepts &
terminology
- Fluviatile, deltaic and turbidite systems in a
sequence stratigraphic context
- Fundamentals of clastic reservoir architecture and
subsurface fluid flow
-
- Clastic reservoir
architecture
- Reservoir rock
typing
- Recovery mechanisms and subsurface fluid
flow
- Static reservoir modelling
workflow
Learning, methods and tools
The course uses a combination of lectures and
paper exercises. The exercises are mostly built around correlation
problems to highlight the importance of using sound
sedimentological and stratigraphic concepts for building
fit-for-purpose subsurface models.
The PPT viewgraphs used and a set of short
briefing notes are provided as a hard-copy hand-out, as well as the
text book 'Sedimentology and Stratigraphy' [Nichols, G., (2009),
Wiley-Blackwell, (2nd Ed.) pp. 419 (subject to
availability)].
Subject to prior agreement a ½ to 1-day workshop / demo on
how to build a static reservoir model [using a Client's own data
set] may be incorporated in the programme. Including such a
workshop / demo in the course will be at the expense of the time
available for one or more of the lecturing modules.
Day by day programme
Day 1
Clastic stratigraphy & sedimentation - basis for subsurface
modeling
- Correlation - key to subsurface modeling
- Fundamentals of clastic reservoir architecture and subsurface
fluid flow
Sea level change - the fundamentals
- Temporal and spatial scales of sea level change
- Relative vs eustatic sea level change
- 'Haq' sea level curve: test case Australia
- Mechanisms of sea level change (Milankovitch cyclicity)
- 'Ice house' vs 'Green house' periods
- Allocyclicity vs Autocyclicity
- Seismic stratigraphy: basis for 'Haq' sea level curve
Day 2
Sequence stratigraphy
- Why sequence stratigraphy matters
- Sediment supply vs accommodation space (Sea level change +
subsidence = accommodation space)
- Sea level change and stratal patterns (Coastal progradation /
aggradation / retrogradation; Transgression / regression; Deepwater
sands)
- Accommodation space and sequence development (Stratal surfaces
& terminology)
- Wheeler diagrams
- Depositional sequences & systems tracts
- Parasequences & (maximum) flooding surfaces
- Forced regressions & incised valleys
- Expression of sea levels changes in fluvial realm
- Sequence stratigraphy vs Genetic stratigraphy
Day 3
Fluvial systems & reservoir characteristics of fluviatile
deposits
- Processes and main facies
- Alluvial fans
- Alluvial valleys
- Braided streams
- Meandering streams
- Anastomosing rivers
- Fluvial distributary channels in deltas
- Fluvial architecture and reservoir geometry
Deltaic coastal systems & reservoir characteristics of
deltaic deposits
- Processes and main facies
- River-dominated deltas
- Wave-dominated deltas
- Tide-dominated deltas
Non-deltaic coastal systems and continental shelves
- Processes and main facies
- Shoreline architecture
- High-energy shelf systems
- Shelf edge and slope
- Log correlation exercise
Lacustrine systems
- Main controls on lake formation
- Processes and main facies
- Preservation potential of lacustrine deposits
- Source rock potential
Day 4
Deep water mass-flow sediment transport:
- Sediment supply to deep water (Rock falls / slumps / debris
flows / grain flows / liquefied flows / turbidity currents)
- Deepwater fan models & prediction of reservoir quality
- Dimensions of deep-water depositional systems
Deepwater mass-flow sedimentary systems
- Sea level low-stand as a control on deep water
sedimentation
- Deep-water fan models (Autocyclicity in deep water fans;
'Shaley sands' in turbidite deposits)
Megaturbidites
- Channel / levee / basin plain deposits
- Seismic characterisation of deep-water clastics (Reservoir
architecture: descriptive terminology)
Gulf of Mexico deep-water clastics
- Salt structures as a control on sea floor topography
(Mini-basin sedimentation)
North Sea deep-water clastics
- Subsurface uncertainty (Commercial discovery instead of 'dry
hole')
Day 5
Clastics vs Carbonates
- Poroperm characteristics of clastics
- Biology: key control on carbonate deposition
- Poroperm characteristics of carbonates (Extreme pore systems:
karst reservoirs)
- Carbonate depositional systems (Tropical / cool-water / mud
mound carbonate factories)
Clastic stratigraphy & sedimentation - impact on field and
reservoir development:
- Reservoir architecture
- Subsurface fluid flow and field development implications
Optional workshop part of course
- Review of participants' data sets / case studies
Course assessment: multiple choice test