Exercises

Modules with Guided Exercises

 

The modules below are tied to lectures, movies and exercises that can be accessed from this web site and used for academic and educational purposes. They have been organized so the user can start with little understanding of but through systematically following the modules in order can improve vocabulary, understanding and experience. Initial materials and exercises are introductory in character but as one moves through the modules, their materials become more sophisticated and challenging. Once the modules have been completed you should have a good unexercise images and exercise solutions should you need them quickly but if you want to know more about the exercises the best path to retrieve them from are the modules listed below.

Introduction

Rational for Sequence Stratigraphic Exercises

Earth scientists involved with reservoi for professionals while teaching principles of Sequence Stratigraphy based reservoir characterization to novitiates. The accompanying text on the site ties relevant data including images, text links, and movies of sedimentary simulations.

 

Concepts that may be learnt from the Exercises

In the exercises below you will learn how:
• Sequence Stratigraphy subdivides the sedimentary section into geometric packages bounded by unconformities and internal Surfaces
• Sedimentary geometries are related to changes in Base level (sea level and/or tectonic movement) and rates of sedimentation
• To predict the extent and character of these sedimentary geometries
• Sequence Stratigraphy is a powerful geological tool that has economic implications in that it can be used to make predictions as to the extent and character of the rocks containing hydrocarbon and water resources


The exercises demonstrate how the above inferences and Sequence stratigraphic analyses is largely based on the interpretation of
• Seismic cross-sections
• Well logs
• Outcrop studies of sedimentary rocks and are used to predict the continuity and extent of their Lithology.

The exercises show how
• Seismic cross-sections can provide regional control on the geometries of Sequences
• Well logs can be used to determine the Lithology of these geometries
• Outcrop studies provide an even more detailed understanding of the Lithology of these geometries.
• The best of interpretations are preferably made with a tie between local outcrops, local wells and local seismic.
• If one or two of these data sources are missing the resulting models may be diminished by their absence.

The exercises using seismic cross-section display how
• To determine the Sequence Stratigraphy of a Basin from discontinuity Surfaces that coincide with seismic reflector Terminations
• Those Surfaces that form the Sequence Boundaries are correlated
• The enveloped system tracts are correlated
• Both Sequence Boundaries and system tracts are traced from line to line to establish the sedimentary architecture of the Basin and infer the origins of the system tracts
• Clinoform geometries can be used to show evidence of delta switching, slumping and migration and related to the shifting of the source areas
• The effects of variable rates of sediment supply in the area of study can be examined
• To determine evidence for widespread changes in Base level
• To locate Basin floor fans, Slope Fans and Incised Valleys and find evidence to demonstrate that these latter were produced during changes in Base level

The exercises using well log character show how well logs can be used to:
• Correlate ParaSequence Set');">ParaSequence Sets at the scale of feet to tens of feet
• Determine the depositional setting of the component system tracts
• Determine the Sequence Stratigraphy of the section being studied
• ParaSequences are identified and correlated from well log character, particularly when planktonic or palynologic biostratigrapic markers are restricted to only a few vertically dispersed shale horizons
• The resulting ParaSequences are often at the same scale as the components of local hydrocarbon reservoirs
• Find, map and exploit these reservoirs more effectively by relating them to eustatic Events

The exercises using outcrops indicate how:
• Outcrops are the ultimate ground truth to the correlation of ParaSequences
• Major Surfaces that include Transgressive Surfaces (TS), Maximum Flooding Surfaces (mfs), and Sequence Boundaries (SB) facilitate this process.
• Stacking Patterns of ParaSequences help determine the continuity of the reservoir quality & depositional setting of the sediments they bound.
• The high-frequency "cycle" or "ParaSequence" is the smallest set of genetically related facies deposited during a single base-level cycle.
• Cycle Boundaries mark the turnaround from base-level fall to base-level rise (a period of time during which sea level rises from a highstand position, through a lowstand, and returns to a highstand).
• Cycles can be mapped across multiple Facies Tracts and include multiple Vertical Facies Successions (VFS) and chronostratigraphic units (Kerans & Tinker, 1997 and Mitchum & Van Wagoner, 1991).
• The commonest ParaSequence is the shoaling upward cycle, with finer deeper water facies at their base and coarser better-sorted facies towards their top.
• ParaSequence Set');">ParaSequence Sets identified in outcrop can be used to identify potential acquifers, aquicludes, hydrocarbon source rocks, reservoirs and seals.

1• Introduction to Sequence Stratigraphy: the critical Stratigraphic Surfaces used Sequence Stratigraphy with their relationship to the exercises briefly outlined.

2• Basics: introduction to Sequence Stratigraphy with a Real Time lecture describing the ideal ‘Sequence' of Vail et al 1977 and its associated terminology.

3• Clastic Sequence Hierachies: uses a movie to show the clastic sedimentary response to changing sea level and rates of sedimentation focusing on the hierachies of geometry found in clastic Sequences.

4• Carbonate Sequence Hierachies: examines the hierarchy of scales expressed by Carbonate strata and provides movies that track the fill of Basins and shelves by Carbonate sediment.

5• Mixed Carbonate & Clastic Basin: a movie of the fill of a sided sedimentary Basin with Carbonate and clastic sediment reviewed.

Exercises

ChronoStratigraphy

1• Exercise 1 - ChronoStratigraphy: construction of a chronostratigraphic chart with the support of a movie that tracks an evolving chronostratigraphic chart and the fill of the associated sedimentary Basin.

Seismic Sequence Stratigraphy

1• Introduction to Seismic Sequence Analysis: the first steps that need to be taken to make a seismic Stratigraphy interpretation and the definition and illustration of genetic reflection packages that envelope Seismic Sequences and Systems Tracts.

2• Exercise 1- Tying a Well Synthetic to a Seismic Line: a seismic cross-section through Little Knife Field tied to a synthetic seismic trace made from velocity log from the Zablotny #1well so determining the local Stratigraphy of the Williston Basin.

3• Exercise 2- Seismic Sequence Analysis: Sequence Stratigraphy of a seismic line across the lower Cretaceous of the offshore of South Africa.

4• Exercise 3- Seismic Sequence Analysis: Sequence Stratigraphy of five regional seismic lines from the National Petroleum Reserve of Alaska (NPRA):

a) Objectives & Data: seismic used to determine the geometric relationship of Sequences, delta migration, local and regional tectonics, and the eustatic signal.

b) Geological Setting: Colville "foreland" Basin initiated in the Jurassic and filled by prograding clinoforms of siliciclastics through the Cretaceous and Tertiary.

c) Class Answer - Sequence Stratigraphy of Lower Cretaceous: slow and constant rate of subsidence with a steady inflow of clastics responding to second and third order eustatic signals in the Cretaceous section with localized higher-frequency (4th order?) Events related to delta migration.

5• Exercise 4 - Seismic Sequence Analysis: Carbonate Sequence Stratigraphy of a regional seismic line from the western Great Bahamas Bank:

a) Objectives & Data: Carbonate Sequence Stratigraphy of the shelf, reef crest, slope and down slope Basin floor fans related to local changes in Base level and the Haq et al (1987) sea level chart.

b) Seismic Line: Cretaceous and Tertiary Carbonate sediments of the western Great Bahamas Bank reflect the effects of changes in sea level.

c) Class Answer – The tie of Sequence Stratigraphy of the Neogene Section to Eustasy: A slow and constant rate of subsidence, and steady flux of Carbonates sediments onto the Great Bahamas Bank caused a close balance between Aggradation and Progradation, while small changes in the rate of Relative Sea Level movement and/or Carbonate Accumulation causing immediate switches from Aggradation to Progradation at the margin.

Outcrop Sequence Stratigraphy - Gateway

1• Introduction to Sequence Stratigraphy of Sedimentary Sections: brief introduction to the use of measured sections to build Sequences stratigraphic models from sedimentary sections.

 

Outcrop Sequence Stratigraphy - Clastics

1• Introduction to Sequence Stratigraphy of Clastic Sections - Book Cliffs, Utah : the first steps in the use of measured sections to build Sequences stratigraphic models of clastic Shoreline Depositional Systems, using measure sections from the Book Cliffs in Utah.

2• Exercise 1 - Measured Section at Kennilworth - Book Cliffs, Utah: introduction to ParaSequence identification on the basis of the lithologies within outcrops. One section is considered and used to identify a vertical set of ParaSequences within a measured section.

3• Exercise 2 - Measured Sections at Panther, Kennilworth & Coal Canyons - Book Cliffs, Utah: three measured sections are correlated using a combination of changes in grain size and depositionals facies to identify the major Stratigraphic Surfaces and ParaSequence Stacking Patterns that are tied from section to section.

4• Exercise 3 - Measured Sections from Gilson Gulch to Coal Canyon - Book Cliffs, Utah: correlation of twelve measured sections in the Book Cliffs and construction of a regional Sequence stratigraphic interpretation of facies geometries using Lithofacies, major Surfaces, and ParaSequences to tie these together.

Outcrop Sequence Stratigraphy - Carbonates

1• Introduction to Sequence Stratigraphy of Carbonates Sections - Miocene Carbonates of Mallorca, Spain the first steps in the use of measured sections to build Sequences stratigraphic models of Carbonate platform and reef Depositional Systems, using measure sections from the sea cliffs lining the south eastern shore of Mallorca.

2• Exercise 1 - Measured Sections at Cap Blanc- Cliffs of Late Miocene Reef Complex: introduction to Carbonate cycle identification on the basis of the Carbonate Lithofacies within outcrops of the Llucmajor reef. Identification of a vertical set of ParaSequences and cycles within a measured section.

3• Exercise 2 - Measured Sections at Cap Blanc- Cliffs of Late Miocene Reef Complex: two to three measured sections are correlated using a combination of predicted trajectories of ParaSequence Stacking Patterns in the Llucmajor reef, changes in Carbonate facies, and major Stratigraphic Surfaces tied from section to section.

4• Exercise 3 - Measured Sections and Wells in the Llucmajor Late Miocene Reef Complex: correlation of wells and measured sections in the Llucmajor using predicted reef trajectories to construct a regional Sequence stratigraphic interpretation of facies geometries that involve Lithofacies, major Surfaces, and ParaSequences that tie them together.

Well Log Sequence Stratigraphy - General Preamble

1• Introduction to Sequence Stratigraphy with Well Logs: the first steps in the use of well logs to build Sequences stratigraphic models of Depositional System.

2• Well Log Suites: brief description of how different types of well log are used to interpret sedimentary geology.

3• Well Log Response Character: explanation of the use of the shapes of well log curves to track changes in mineral content, and grain size and so interpret sedimentary geology.

4• Well Log Stacking Patterns: explanation of how Aggradational, Retrogradational and Progradational Stacking Patterns identified on well logs can be used to interpret sedimentary depositional settings.

 

Well Log Sequence Stratigraphy - Clastic High-Frequency Signals

1• The Geologic setting of the La Pascua Formation - Guarico Sub-Basin: general geological setting of the nearshore clastics of the Lower Oligocene La Pascua Formation of the Las Mercedes Field in the West Guarico Block, Venezuela, their Lithology, relationship to sea level and plate tectonic setting.

2• Introduction to Sequence Stratigraphy of the La Pascua Formation - Guarico Sub-Basin: first steps in the use of well logs to build Sequences stratigraphic models of clastic Shoreline Depositional Systems for the Lower Oligocene La Pascua Formation of the Las Mercedes Field in the West Guarico Block, Venezuela.

3• Exercise 1 - Well log correlation using SP & RES logs: interpretation of local north eastern Venezuelan clastic Stratigraphy using three wells (W-1, W-2, W-3) that penetrate the Lower Oligocene La Pascua Formation of the Las Mercedes Field in the West Guarico Block.

4• Exercise 2 - Well log correlation using SP & RES logs: interpretation of local north eastern Venezuelan Stratigraphy and identification of a clastic Sequence in an Incised Valley using 10 wells (W-1 to W-10) that penetrate the Lower Oligocene La Pascua Formation of the Las Mercedes Field in the West Guarico Block.

5• Exercise 3 - Well log correlation using SP & RES logs: interpretation of local north eastern Venezuelan Stratigraphy and identification of a clastic Sequence of an Incised Valley, and its relationship to sea level from 22 wells (W-1 - W-22) that penetrate in the Lower Oligocene La Pascua Formation of the Las Mercedes Field in the West Guarico Block.

6• Exercise 4 - Well log correlation using SP & RES logs: interpretation of local north eastern Venezuelan Stratigraphy and identification of a clastic Sequence of an Incised Valley, and its relationship to sea level from 5 Wells (me333, me296, me428, me313 and me 486) within the central portion of the Northern Strike Line that penetrate in the Lower Oligocene La Pascua Formation of the Las Mercedes Field in the West Guarico Block.

7• Exercise 5 - Well log correlation using SP & RES logs: interpretation of local north eastern Venezuelan Stratigraphy and identification of the clastic coastal and Incised Valley Sequences, and their relationship to sea level from wells that penetrate in the Lower Oligocene La Pascua Formation of the Las Mercedes Field in the West Guarico Block on a North-South Dip line , a Northern Strike Line and a Southern Strike Line.

8• Solutions for Exercise 1, 2, 3, 4 and 5: interpretation of well log cross-sections of coastal sedimentation and Incised Valley fill explained with a movie of the evolving clastic Sequences.

9• References: References for the interpretation of Well logs and References for the Guarico Sub-Basin geological framework and regional Stratigraphy.

 

Core& Well Log Sequence Stratigraphy - Carbonate High Frequency Signals

1) Introduction to high frequency Carbonate Sequence Stratigraphy: an explanation of why cycles and ParaSequences are used to study ancient Carbonate systems

2) Exercises that introduce high frequency Carbonate Sequence Stratigraphy with an "hypothetical" example: Introduction to use of well log interpretation of Carbonates using awell-log section across the imaginary Ordovician Carbonate margin of the "Beltzaren Lurraldean Field in NW Syldavia" (After Hergé 1939)
Exercise 1
Introduction to ParaSequence identification using well logs to identify the major Stratigraphic Surfaces and cycle (and/or ParaSequence) Stacking Patterns tied from well to well.
Exercise 2
Well logs correlated using a combination of well logs and cores to identify the major Stratigraphic Surfaces and cycle (and/or ParaSequence) Stacking Patterns that are tied from well to well.

Under Development) EXERCISE:- Well log section of Upper Jurassic of the "Pearl Banks offshore Abu Dhabi Basin" (After xxx & xxx, 2002)
Exercise 1
Introduction to ParaSequence identification on the basis eight well logs to identify the major Stratigraphic Surfaces and cycle (and/or ParaSequence) Stacking Patterns tied from well to well.
Exercise 2
Eight well logs correlated using a combination of well logs, seismic and strontium isotope ages to identify the geometry of major Stratigraphic Surfaces and cycle (and/or ParaSequence) Stacking Patterns that are tied from well to well.

EXERCISE:- A well log cross-section across the margin of "NE shelf of the Delaware Basin of the Permian Basin" in New Mexico and the NW flank of the Central Basin Platform (After Harris & Saller 1999).
Exercise 1
Introduction to cycle (and/or ParaSequence) identification on the basis well logs to identify the major Stratigraphic Surfaces and cycle (and/or ParaSequence) Stacking Patterns tied from well to well.
Exercise 2
Well logs correlated using a combination of well logs and seismic tied to synthetic to identify the geometry of major Stratigraphic Surfaces and cycle (and/or ParaSequence) Stacking Patterns that are tied from well to well.
Exercise 3
Fill in details of lithofaceis on partly interpreted well log section with inFormation gleaned from interpreted seismic and establish cycle (and/or ParaSequence) Stacking Patterns that are tied from well to well.

3) Correlation of cycles and/or ParaSequences; cycles and/or ParaSequence Set');">ParaSequence Sets; and Systems Tracts in the Hanifa Formation: based on Stacking Patterns & log character. A description of the Surfaces that bound and subdivide ParaSequences and how they are identified on well logs. How to construct Fischer Diagrams.

Exercise 1
Introduction to ParaSequence identification on the basis of the lithologies within cored wells. Well # 1 penetrates a shallow shelf region and Well # 2 a deeper region.

Exercise 2
Four well logs correlated using a combination of well logs and cores to identify the major Stratigraphic Surfaces and ParaSequence Stacking Patterns that are tied from well to well.

Exercise 3
The use of 14 (Fourteen) well logs to make a regional Sequence stratigraphic interpretation of facies geometries by identifying major Surfaces, establishing the Lithofacies, building a Fisher diagram.

Exercise 4
Improve high frequency cycle correlation using the Fischer Diagram.

References
Monday, April 08, 2013
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