Introduction to Stratigraphy What is stratigraphy

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Introduction to StratigraphyWhat is
stratigraphy?

• Stratigraphy
• the study of large-scale vertical and lateral
  relationships between units of sedimentary rock
  that are defined on the basis of lithological or
  physical properties, paleontological
  characteristics, geophysical characteristics,
  geophysical properties, age relationships and
  geographic position and distribution. (i.e., its
  the filing system for the rock record)
• Stratigraphy is based on Stenos and Huttons
  laws.
• The fact that rocks were originally laid down in
  a fluidized form was noted by medieval and
  renaissance scientists (e.g. Steno, Da Vinci).
• Modern sequence stratigraphic concepts stem from
  work of Grabau (1906), Blackwelder (1909),
  Barrell (1917), Wheeler (1958) and Sloss (1963).

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Formal Schemes(as espoused by the NACSN,
1982)

• Lithostratigraphy
• Allostratigraphy
• Sequence Stratigraphy
• Genetic Sequence stratigraphy
• Depositional sequence stratigraphy

• Biostratigraphy
• Chronostratigraphy
• Cyclostratigraphy
• Magnetostratigraphy
• Pedostratigraphy
• Event Stratigraphy
• Morphostratigraphy

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Informal Schemes

• Lithostratigraphy
• Allostratigraphy
• Sequence Stratigraphy
• Genetic Sequence stratigraphy
• Depositional sequence stratigraphy

• Biostratigraphy
• Chronostratigraphy
• Cyclostratigraphy
• Magnetostratigraphy
• Pedostratigraphy
• Event Stratigraphy
• Morphostratigraphy

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(NACSN, 1981)
(Holbrook, 2001)
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Warning Signs on the Road Ahead
Sequence Vs Seismic
Descriptive Genetic?
Van Wagoner et al. (1988)
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Quaternary oxygen isotope stages
(Stanley, 2005)

• Grabau (1906)
• principles of sedimentary overlap.
• Showed onlap, offlap relationships in Paleozoic
  strata of North America.

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Penn. cyclothems

• Barrell (1917)
• recognized relationship between time and
  stratigraphy.
• This figure was driven by early attempts to use
  sedimentation rates to calculate the age of the
  Earth.

(Stanley, 2005)
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Sloss Sequences
(Stanley, 2005)
Wheelers diagram
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The Seismic Revolution in subsurface stratigraphy

• Explosion of subsurface data driven by need to
  fuel WW1 and WW2.
• Development of Well logs, Cores and Seismic
• Seismic data was acquired for petroleum
  exploration during latter half of the 20th C.
• Seismic imaging developed form technology used in
  WW2 to locate submarines.
• Sub-sea floor images also produced.
• Several advantages
• Provided continuous subsurface image of
  sedimentary basin fills.
• Structure and stratigraphic relationships
  observed in areas not previously accessible.
• Could compare seismic data from around the world.
  
• Scientists at Exxon recognized the stratigraphic
  significance of the seismic tool (Vail et al.,
  1977).
• New data amenable to analysis using concepts
  developed by Wheeler and others.
• Developed science of seismic stratigraphy.

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Accommodation
Accommodation
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Lapping Relationships
Parasequences
(Posamentier and Allen, 1999)
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Parasequence sets
Parasequences in well logs
(Van Wagoner, et al., 1990)
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(Van Wagoner, et al., 1990)
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(Van Wagoner, et al., 1990)
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Missing In Action?
Type 2 Sequence Boundary?
Shelf-Margin Wedge?
(AGI Data Sheets, Holbrook)
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Ramp-type Basins
(Van Wagoner, et al., 1990)
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Normal Regression
Forced Regression
(Posamentier and Allen, 1999)
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Ramp-type Basins
(Van Wagoner, et al., 1990)
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Sequence-Stratigraphic Surfaces
(Embry, 2002)
(Embry, 2002)
(Holbrook, AGI data sheets)
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Contrasting Views on Normal vs. Forced Regression
Hunt and Tucker (1992) sequence boundary
Lowstand Lowstand (Posamentier, et al 1992) Or
Falling Stage (Hunt and Tucker, 1992)
Posamentier, et al., (1992) sequence boundary
(Posamentier and Allen, 1999)
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(Embry, 2002)
(Embry, 2002)
(Holbrook, AGI data sheets)
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Importance of Correlation in Defining Surfaces
(Outcrop)
(Stanley, 2005)
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Importance of Correlation in Defining Surfaces
(Subsurface)
Sequence Boundaries Correlated in Well logs
mfs in Seismic
(Posamentier and Allen, 1999)
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Sequence Boundaries
Spatial Variability in Surfaces
(Holbrook, AGI data sheets)
(Posamentier and Allen, 1999)
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Differential Incision of Valleys and Channels and
the continuity of Sequence Boundaries
Cooper Creek Australia
Colville Delta
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(Holbrook, AGI data sheets)
Hanging-valley Sequence Boundaries
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Multivalley Surface in
Mesa Rica
(Holbrook, 2001)
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Regionally Continuous Surfaces
The Lower Mesa Rica Sandstone is an 84-km
Single-Story Channel Sheet
Lower Mesa Rica Sandstone
(Holbrook, et al, 2006)
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Recognizing Incised Valleys
Terrace architecture in the Trinity River, Gulf
Coastal Plain (Blum, 2006)
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Terraces in
(Holbrook, 2001)
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Importance of Channel Stacking
(Holbrook, 2001)
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2
3
1
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Importance of Channel Dimension
Some Typical channel depths Lower Mississippi
18m Lower Missouri 7m Middle Rio Grande 3m
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Incised Valley on 3-D Seismic
(Posamentier and Allen, 1999)
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Importance of truncations and facies shifts
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Valley fill types
Cap of marine Graneros Shale
Fluvial fills
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Gironde Estuary Model (Posamentier and Allen,
1999)
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Tidal Ravinement
Courtesy of Brian Willis
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Sequence Boundaries vs. Settings (Alluvial)
Fluvial-on-Fluvial SBs
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Sequence Boundaries vs. Settings (Alluvial)
View of cliff, parallel to flow
(Adams and Bhattacharya, 2005)
Castlegate
Blackhawk
BLACKHAWK Laterally continuous 5-8 m-thick
channel-belts encased in floodplain
deposits. CASTLEGATE Amalgamated 4-7 m-thick
channel-belt sandstones
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Sequence Boundaries across the shelf
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Interfluvial Sequence Boundaries vs. Parasequence
tops
(Posamentier and Allen, 1999)
(Van Wagoner, et al., 1990)
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Correlative Conformity
(Embry, 2002)
(Posamentier and Allen, 1999)
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Regressive Surface of Marine Erosion
(Posamentier and Allen, 1999)
(Embry, 2002)
(Posamentier and Allen, 1999)
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Transgressive Surfaces (TS)
TS
TS
(Lockley et al, 2006)
Colorado River Valley, Texas
TS
TS
Highstand
Falling Stage/ Lowstand
TS
(Blum, 2006)
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Transgressive Surface of Erosion (TSE)
(Posamentier and Allen, 1999)
(Posamentier and Allen, 1999)
(Holbrook, AGI data sheets)
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Maximum Flooding Surfaces
(Van Wagoner, et al., 1990)
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Maximum Flooding Surfaces
Carbonate zone between fossiliferous marine
shales Condensed Section?
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Maximum Flooding Surfaces Cautions!
Extended View
Philoid algal mounds in Penn. Fort Worth Basin,
Texas
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Maximum Flooding Surfaces
(Posamentier and Allen, 1999)
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Architectural-Element Analysis
(Miall, 1996)
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Fluvial Architectural Elements
Downstream accretion element
Sandy bed form
Gravel bar element
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Fluvial Architectural Elements
Overbank fine
Lateral accretion element
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Primary Architectural Elements
Submarine Fan Architectural Elements
(Posamentier and Kolla, 2003)
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Submarine Fan Architectural Elements
(Posamentier and Kolla, 2003)
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AEA The Technique
(Miall, 1996)
(Holbrook, 2001)
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Fluvial Example
(Holbrook, 2001)
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Fluvial Example
5
2
3
1
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Eolian example
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Eolian example
(Permian Cedar Mesa c.o. Rip Langford)
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Eolian example
(Permian Cedar Mesa c.o. Rip Langford)
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Sequence Boundaries and Architectural Hierarchies
Sequence Boundaries
(Holbrook, 2001)
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Sequence Boundaries vs. Architectural Hierarchies
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(Holbrook, 2001)
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(Van Wagoner, et al., 1990)
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Drapes on Reactivation Surfaces
Drapes on Dune/Ripple Sets
Drapes between Dune Sets (1st)
0 - 2nd - Order Drapes
Drape on Dune Sets (2nd)
Migrating Dune Sets
Drapes on Reactivation Surfaces (0)
(Holbrook and Ikuenobe, 2002)
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Low- Stage Filling
3rd - 4th-Order Drapes Nested Channel and Bar
Surfaces
(Holbrook and Ikuenobe, 2002)
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High- Stage Cutting
Channel and Bar Draping
3rd - 4th-Order Drapes Nested Channel and Bar
Surfaces
(Holbrook and Ikuenobe, 2002)
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3rd - 4th- Order Drapes
(Holbrook and Ikuenobe, 2002)
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5th - and 6th - Order Surfaces Channel and
Channel-Belt Scours
(Holbrook and Ikuenobe, 2002)
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Origin, Muddy Sandstone Sheets
Dominance of Basal Channel Fill Under Conditions
of Intensive Reworking and Low Accommodation
Space
(Holbrook and Ikuenobe, 2002)
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7th - and 8th - Order Surfaces Valley and
Nested-Valley Scours
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7th - and 8th - Order Surfaces Valley and
Nested-Valley Scours
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7th - and 8th - Order Surfaces Valley and
Nested-Valley Scours
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2
3
1
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Sequence Boundary
9th - Order Surfaces Sequence Boundaries
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Implications

• Few surfaces generate sufficiently continuous
  barriers to compartmentalize a reservoir, but
  they can inhibit flow, locally form pocket traps,
  and reduce production from estimated levels.
• Low-order surfaces impose strike- and
  dip-oriented permeability grains that operates at
  the scale of wells, whereas high-order surfaces
  impose a dip-oriented grain that operates at the
  scale of fields and wells.
• Only the highest-order surfaces may be traced
  between wells routinely.
• A general relationship exists between
  sequence-boundary morphology and architecture of
  overlying fluvial sandstone.

(Holbrook and Ikuenobe, 2002)