Oil and Gas

Oil and Gas | Stratigraphy

Practical Methods for Sequence Stratigraphic Prediction

Course Code: N349
Instructors:  John Snedden
Course Outline:  Download
Format and Duration
5 days

Summary

Sequence stratigraphy has proven useful in the identification of critical elements of the petroleum system: reservoir, seal and source. This course avoids the academic debate on nomenclature and eustasy and focuses upon time-tested methods for hydrocarbon identification and exploitation using well logs, cores and seismic. Using a large number of real world examples, participants learn methods applicable to compartments, fields,  prospects, plays and basins. Conventional and unconventional reservoirs are considered.

Feedback

I thought this was a great class. The exercises were very applicable and helped to clarify the lecture material. This class really helped increase my knowledge of sequence stratigraphy and gave me good strategies for applying it.

Duration and Training Method

A five-day classroom course comprising of well-illustrated classroom lectures set up 20 hours of practical seismic interpretation and well log correlation exercises. Special media (.avi movies) of experimental and numerical models support concepts and theory.

Course Overview

Participants will learn to:

  1. Discriminate between lithostratigraphy and chronostratigraphy and understand how sequence stratigraphy improves exploration, development and production success.
  2. Assemble data for seismic stratigraphic analysis and contribute to planning and implementation of seismic stratigraphic projects to address play element uncertainty.
  3. Discuss methods for creating seismic facies maps using workstation seismic interpretation software.
  4. Evaluate well logs for characteristic patterns indicating system tracts, sequences and sequence sets and understand differences between low- to high-order.
  5. Assess stratal terminations to identify and correlate key surfaces (sequence boundaries, maximum flooding surfaces) on various types and vintage of reflection seismic data.
  6. Integrate biostratigraphic and physical stratigraphic observations from well data to establish local/global chronostratigraphic designations of depositional sequences.
  7. Evaluate and map non-amplitude based seismic facies and combine with isochore and amplitude maps to predict reservoir distribution.
  8. Assess other key elements of petroleum systems (seal, source, and stratigraphic trap) from integration of seismic and well data.
  9. Understand how source to sink analysis (advanced provenance work, empirical scaling relationships) supplement and enhance the sequence stratigraphic approach to basin analysis. 

Introduction

  1. Principles: lithostratigraphy (rock), biostratigraphy (faunal abundance, ranges, datums), chronostratigraphy (time-rock)
  2. Why chronostratigraphic correlation is better than lithostratigraphic correlation 
  3. Defining surfaces: sequence boundary, flooding surface, transgressive surface, maximum flooding surface and systems tracts (highstand, transgressive, and lowstand)
  4. Hierarchy of sequence stratigraphy: from supersequences to parasequences (to bedset, bed, laminaset, etc.)
  5. Sequence stratigraphy from non-marine to deep marine; sandstones, carbonates and shale reservoirs
    Exercise: ACCOMMODATION EXERCISE (Wheeler Diagram)

Supersequences and Sequences: basin and play scale (emphasis on seismic stratigraphy)

  1. Basics of seismic interpretation
  2. Why seismic reflections follow chronostratigraphic boundaries instead of lithostratigraphy
  3. Stratal terminations:
    - Angular truncation, toplap, onlap, downlap: discrimination and prioritization
    - Relationship of surfaces and terminations to systems tracts: identification on seismic:
    Exercise: STRATAL TERMINATIONS (forward seismic model)
  4. Mapping seismic sequences (methodology and data preparation)
  5. Seismic facies analysis from shallow to deepwater:  geometry, amplitude, frequency and continuity of seismic reflections
  6. Source to sink correlation: hinterland to abyssal plain seismic examples
  7. Exploration play analysis from a sequence stratigraphic perspective
    Exercise: CLINOFORM SEISMIC CORRELATION EXERCISE (Main Pass, Louisiana)

Chronostratigraphy

  1. Seismic facies stratigraphic observations with biostratigraphy and other age-constraining information
    Exercise: CHRONOSTRATIGRAPHIC DESIGNATION (Ferron Group, Utah)

Systems Tracts and Parasequences: regional and field scale (emphasis on logs and cores)

  1. Reservoir content, continuity, and quality by systems tract
  2. Stacking patterns in logs, cores, and outcrops; relationship to key surfaces
    Exercise: PARASEQUENCE LOG CORRELATION (South Louisiana Miocene)
  3. Recognition of sequence boundaries, flooding surfaces, and maximum flooding surfaces in cores and logs
  4. Log motifs from alluvial to deep marine paleoenvironments; shale continuity by paleoenvironment and sequence stratigraphy
  5. Alluvial channel, channel belt, and valley-fill
  6. Lobes, lobe complexes and storeys in deltaic and deepwater distributive systems

Combining Seismic and Log Correlations

  1. Data Preparation, analysis and interpretation: seismic displays (wiggle trace vs. variable density displays) and loop-tying horizons
    Exercise: DIFFERIENTIATING STRUCTURE AND STRATIGRAPHY (Orange Basin, South Africa, North Slope Alaska)
  2. The art of well ties (synthetic seismograms), and understanding seismic amplitude maps
    Exercise: WELL-TIE EXERCISE, WILLISTON BASIN, NORTH DAKOTA (Bakken Shale)
  3. Seismic facies classification: amplitude-dependent and ‚Äďassociated; non-amplitude class
  4. Combining A-B/C seismic facies maps with amplitude maps
  5. Seismic facies on the workstation: pseudo-fault and pseudo-horizon techniques  
    Exercise: MIOCENE SHELF-SLOPE-BASIN CORRELATION AND SEISMIC FACIES MAPPING EXERCISE
    - correlation of well logs from shelf to slope; identification of sequence boundaries and maximum flooding surfaces
    - tie wells to 2D seismic lines with synthetic seismograms; interpret seismic lines and loop tie correlations;
    - identify and map seismic facies; map shelf margins; relate both maps to seismic amplitude map pattern. Pick development well and near-field wildcat locations. Report-out as teams.

Source to Sink Analysis

  1. Predictive capability of the sequence stratigraphic approach is enhanced by identification of large, well-integrated drainage systems which often feed large submarine fans
  2. Point bar size is a reliable proxy for river catchment size within a climatic regime
  3. Role of advanced provenance analytical approaches like Detrital Zircon geothermometry in source to sink reconstructions
    Exercise: SOURCE TO SINK ANALYSIS, LOWER MIOCENE WATER EXPLORATION
  4. Use empirical scaling relationships for fluvial systems to predict submarine run-out length




This course has been designed for working geoscientists who wish to learn practical methods that can be used in the workroom and on the workstation.

John Snedden

Background

John W. Snedden is a Senior Research Scientist at Institute for Geophysics, The University of Texas at Austin. He is director of the Gulf Basin Depositional Synthesis project, a consortium dedicated to research on the depositional history of the Gulf of Mexico. Prior to taking his current position, he worked in the oil industry for 25 years, exploring basins around the world. He has taught more 50 industry short courses on the Gulf of Mexico, sequence stratigraphy, and reservoir connectivity. His publications have been cited more 1400 times (Google Scholar). He has been recognized by awards from the American Association of Petroleum Geologists, SEPM (Society of Sedimentary Geology), and the Gulf Coast Association of Geological Societies. John has published over 35 scientific papers; he is the first author on 25 of these. John has history of leadership in technical societies such as SEPM and the Gulf-Coast Section of SEPM. John has also served as technical chair of several large AAPG conventions. He is lead author of the book, The Gulf of Mexico Sedimentary Basin: Depositional Evolution and Petroleum Applications, Cambridge University Press, November 2019. (doi:10.1017/9781108292795.)

In 2021, John was awarded the Doris Malkin Curtis Medal by the Gulf Coast Section of SEPM, citing his numerous contributions to the understanding the depositional systems of the Gulf of Mexico superbasin.

Affiliations and Accreditation
PhD Louisiana State University, Baton Rouge, LA
MS Texas A&M University, College Station, TX
BA  Trinity University, San Antonio, TX

Courses Taught
N043: Gulf Of Mexico Petroleum Systems
N342: Compartmentalization and Connectivity in Sandstone Reservoirs
N343: Depositional Evolution of the Gulf of Mexico Sedimentary Basin
N349: Practical Methods for Sequence Stratigraphic Prediction

CEU: 4.0 Continuing Education Units
PDH: 40 Professional Development Hours
Certificate: Certificate Issued Upon Completion
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