Practical AVO and Seismic Inversion with Petrel

A profitable development of an oil or gas field starts with a good understanding of the subsurface as a basis for efficient and successful field management. The integration of AVO and inversion techniques in Quantitative Interpretation helps to create the best possible petrophysics subsurface model. Improved discrimination of reservoir units are made and models are generated using logs and seismic data. These techniques lead to highly accurate or highly probable (static) subsurface models compatible (if correctly up-scaled) to dynamic reservoir models obtained from reservoir engineering measurements and computations.

The correct use of seismic attributes, well data analysis, AVO and seismic inversion is essential to establish subsurface models that can be used for improved field development planning and design.

Learning, methods and tools:

This course has Petrel exercises to reinforce learning 

At the end of the course participants will understand basic concepts in quantitative seismic analysis and interpretation based on AVO, well-to-seismic calibration and inversion techniques. Participants will consolidate their understanding of modern technology with recent field study examples and practical workshop exercises.

1

• Introduction
• Basic Concepte
• Seismic Processing for AVO and inversion
• Exercise - Pre-stack Seismic Interpretation
• Exercise - Angle stack creation
• Exercise - Non-Rigid Matching

2

• AVO Theory
• AVO Classificationsand DHI's
• Exercise - AVO Forward Modeling
• Practical applications of AVO analysis – fluid factor, intercept and gradient etc.
• Exercise - AVO Attributes

3

• Inversion Theory and Methods
• Exercise - Post-stack inversion
• Well to seismic ties and wavelets
• Exercise - Seismic Well Tie

4

• Low frequency model building
• Exercise - Low frequency model building
• Practical applications of seismic inversion - including lithology discrimination and rock physics inversion.
• Exercise - Pre-stack seismic inversion

5

• 4D and 3C Inversion
• Exercise - Using Inversion Results
• Stochastic Inversion
• Latest Developments - joint EM-Seismiic Inversion, AVAZ, Zoeppritz Inversion

Global Tectonics and Geological Prospecting Tools for Exploration

This hands-on 5-day course utilizes lectures and practical exercises to introduce key concepts of an effective petroleum system with emphasis on global tectonics and how basins are formed, filled and deformed, and on learning key geologic prospecting tools for exploration. The Atlantic Margin basin is used as an example to discuss the elements of the petroleum system. Clastic rocks are emphasized (especially turbidites) but carbonate rocks and evaporite formation is also reviewed.

Discussions include introduction of key aspects of source rock, migration, overburden rock, reservoir characteristics including porosity, permeability and architecture,  seal rock characteristics, structural and stratigraphic traps, timing and preservation elements.

Prospecting Tools covered in this course include petrophysics for exploration geoscientists , bio- and sequence stratigraphic applications, essential log correlation workflow and log annotation methods, data contouring and mapping, applications of multiple working hypotheses, and utilization of direct hydrocarbon indicators to exploration. Students correlate various logs that illustrate faulted sections and straitigraphic variation, and create contour maps and learn to properly present faults in map view.

1

Objectives and Overview of Module and Course

Five Laws of Geology: Uniformitarianism, Superposition, Original Horizontality, Cross Cutting Relationships, and Walther's Law

Petroleum Systems – components, definitions, and assessment

Basin Formation

Plate Tectonics and the Wilson Cycle

Source Rocks in Conventional and Unconventional Petroleum Systems

Basin Filling – clastics

Carbonates and Dolomitization

Clastic Depositional Models - Fluvial

2

Clastic Depositional Models – Delta and Deepwater Turbidite

Walthers Law

Faulting as migration pathways and/or seals

Review of Fault Types

Hydrocarbon Traps - Good and Bad

Salt Deformation

Review of exploration in Salt Basins

Sutures and Inclusions

Rubble Zones and Imaging below Salt

3

Petrophysics for Exploration

Rock and Fluid Properties

Porosity and Permeability

Pressure and Compaction

Compartmentalization

Tool Applications

Biostratigraphy and Sequence Stratigraphy

Accomodation Space

Stratigraphic Sequences HST, FSST, LST, TST

Carbonate vs Clastic Sequence Stratigraphy

Seismic Sequence Stratigraphy

4

Log Correlation Purpose and Methods

Correlations for Structure

Geological Scenarios for correlation

What to Correlate? Log Headers

Facies Correlation and accounting for Faults

Using Seismic to aid correlation

5

Mapping and Contouring – Definitions and Principles

Creation of various types of contour map

Multiple working hypotheses

Contouring with Faults

Isopach Maps

DHI Concepts for Exploration

Seismic interpretation and Anomolies

Gas Effects and Bright Spots

Prospecting with DHI's

4D Seismic and Electromagnetic Data

Economics of Petroleum Exploration

Participants will learn how to take hydrocarbon volumes and risks and apply a structured decision analysis process to them.  The portfolio optimization process will also be discussed in order to help participants understand how to select the “best” exploration projects.

The comparison of exploration projects under different fiscal regimes will be presented by incorporating discounted cash flow and net present value.  The basics of decision analysis for exploration will be reviewed using sensitivities, decision trees, expected monetary value, and the value of information. 

1

The Business of Exploration

• Why companies explore
• The value chain in the E&P industry
• Justification for exploration
• How a company’s vision, mission, and strategy drive exploration

Participants will learn why companies explore and what metrics are used to measure the success of an exploration program.  The justification of exploration projects will be discussed.  How a company's vision, mission, and strategy drive exploration and other parts of the E&P business will also be presented and discussed.

2

Impact of Worldwide Fiscal Regimes on Exploration

• Overview of worldwide fiscal regimes
• Impact of fiscal regime on exploration
• Comparing projects under difference fiscal regimes

The main types and elements of fiscal regimes around the world will be presented.  Participants will learn to build cash flows for concessionary systems and simple production sharing contracts.  Different types of service agreements will be reviewed, then investments under different fiscal regimes will be compared.

3

Project Economics

• The role of project economics
• Calculating cash flow
• Economic indicators
• Net present value

The participants will receive an overview of petroleum economics, including an introduction to basic cash flow and net present value.  A review of time value of money concepts and cash flow basics will also be presented.  Common economic indicators and project selection fundamentals will be discussed.

4

Decision Analysis

• Sensitivity analysis
• Decision trees
• Expected monetary value
• Value of Information

Participants will gain an overview of important concepts and examples of decision analysis.  The uncertainties, risk, and various ways of incorporating them in the oil and gas project evaluations will be discussed.  The use of a proven decision analysis process including sensitivities, decision trees, and the value of information in both deterministic and probabilistic approaches to evaluating oil and gas projects will be the key concepts covered.

5

Portfolio Analysis

• Portfolio analysis
• Exploration strategies in portfolio management
• Bringing it all together, from play ranking to EMV

Participants will learn about portfolio level analysis and why it is especially important for companies involved in exploration.  Also, portfolio management strategies involving exploration will be discussed.  Finally, participants will work a comprehensive problem to determine play ranking in their portfolio.

Mapping the Subsurface

The context of this course will take the student through the primary techniques of construction of 2D (two dimensional) maps and sections of the subsurface, including integration well data and key surfaces defining the framework of geologic units in the subsurface as the foundation of subsurface evaluation.  These initial 2D techniques allow the interpreter to display the 3D (three dimensional) relationships of geologic surfaces and any associated faults which are the key to defining the spatial and volumetric aspects of the associated subsurface resource. The geologic surface and fault relationships analyzed in this course will also be linked to the overall aspects of depositional settings and structural styles that are present within global development of geologic terrains.

As part an integrated cross-discipline subsurface evaluation team geologists, geophysicists, petroleum engineers and drillers will utilize the techniques presented in this course to interpret subsurface data and provide geological models that form the basis for development planning and resource optimization.

This course is primarily in two sections. The first section is over 3 days of analysis of traditional 2D mapping techniques. The second section extends the traditional 2D hand drawn techniques into a 2 day presentation of computer mapping processes.

1

• Introduction
• Course Objectives, History and Principles of Surface Mapping Across Structural Styles
• Data Quality Issues and Impacts on Mapping
• Contouring Rules and Techniques, Manual vs. Computer Processes there Pluses and Minuses
• Gridding Algorithms and Data-specific Mapping Evaluation: Comparison and Analysis of Gridding Technique results

2

• Wellbore Correlation of Vertical and Directional Drilling Data to Subsurface Feature Mapping
• Hands on Mapping Exercises

3

• Fault Surface Mapping and contouring Techniques
• Rules and Techniques for Integrating Fault and Surface Maps
• Hands on Mapping Exercises
• Application of Fault and Surface Mapping Techniques to Structural Styles: Strike-Slip, Growth, Compressional, and Thrust                                 
• Balanced Cross Sections and Surface Mapping Reconstruction

4

• Petrel Mapping Introduction – Computer Hands on
• Volumetric Calculation from Surface Mapping techniques

5

• Final computer contouring techniques
• Paper Team Exercise in mapping from well correlations, tops, surfaces and fault.
• Conclusion team presentation of results.