AVO and Seismic inversion

This course is delivered in 4 hour segments over 5 days. The course is delivered by virtual means using Skype for Business.

A profitable development of an oil or gas field start with a good understanding of the subsurface as a basis for efficient and successful field management. The use of AVO and inversion techniques 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.

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.

1

Session One (4 hours)

  • Introduction
  • Seismic Processing for AVO and Inversion

2

Session Two (4 hours)

  • AVO Theory Practical applications of AVO analysis – fluid factor, intercept and gradient etc.
  • Well to seismic ties and wavelets

3

Session Three (4 hours)

  • Inversion theory and methods
  • Low frequency model building

4

Session Four (4 hours)

  • Practical applications of seismic inversion - including lithology discrimination and rock physics inversion.
  • 4D Inversion

5

Session Five (4 hours)

  • 3C Inversion
  • Stochastic Inversion
  • Future directions – joint EM-seismic inversion, AVAZ, VSP inversion, full waveform

Rock Physics - Integrating Petrophysical, Geomechanical, and Seismic Measurements

Rock Physics is a key component in oil and gas exploration, development, and production. It combines concepts and principles from geology, geophysics, petrophysics, applied mathematics, and other disciplines.  Rock physics provides the empirical relationships, understanding and theory to connect petrophysical, geomechanical and seismic data to the intrinsic properties of rocks, such as mineralogy, porosity, pore shapes, pore fluids, pore pressures, stresses and overall architecture, such as laminations and fractures. Rock physics is needed to optimize all imaging and reservoir characterization solutions based on geophysical data, and to such data to build mechanical earth models for solving geomechanical problems. Attendees will obtain an understanding of the sensitivity of elastic waves in the earth to mineralogy, porosity, pore shapes, pore fluids, pore pressures, stresses, and the anisotropy of the rock fabric resulting from the depositional and stress history of the rock, and how to use this understanding in quantitative interpretation of seismic data and in the construction of mechanical earth models. A variety of applications and real data examples is presented.

1

  • Introduction
    • What is Rock Physics?
    • Rock Physics and Petrophysics. What’s the difference?
  • Hooke’s law, anisotropy and elastic wave velocities
  • Sedimentary rocks as heterogeneous media
  • The concept of the Representative Elementary Volume (REV) and effective elastic properties
  • Voigt/Reuss and Hashin-Shtrikman bounds
  • Modulus-porosity relations for clean sands
  • Critical porosity and mechanical percolation
  • Gassmann’s equations and fluid substitution
  • Fluid properties and mixtures 

 

2

  • Diagenetic and sorting trends in velocity-porosity data
  • Velocity-porosity models for shaly sands
  • Empirical relations between velocity and porosity, clay content, etc.
  • Properties of sand-clay mixtures
  • Velocity-porosity relations for shales
  • Relations between VPand VS
  • Rock compressibilities and relation of 4D seismic to well testing
  • Reflection coefficients and AVO
  • Elastic impedance
  • Rock physics templates
  • Effective medium and effective field theories
  • Velocity-porosity relations for carbonates

 

3

  • Biot theory
  • Patchy saturation
  • Squirt flow
  • Sediment compaction and the state of stress in the Earth
  • Pore pressure and the concept of effective stress
  • Poroelasticity
  • Application to pore pressure prediction 

 

4

  • Fracture gradient and 3D stress modeling
  • Effect of stress on seismic body waves
  • Third-order elasticity
  • Granular media and discrete element methods
  • Displacement discontinuity methods
  • Stress sensitivity of sandstones
  • Stress sensitivity of shales
  • Stress perturbations around a borehole
  • Determination of velocity variations around a borehole from advanced sonic logging
  • Application to wellbore stability
  • Reservoir geomechanics and stress effects in 4D seismic monitoring 

 

5

  • Fractured reservoirs
  • Hydraulic fracture propagation in presence of natural fractures
  • Seismic characterization of fractured reservoirs
  • Modeling the response of a fractured reservoir
  • Rock physics models for fractures
  • Shales and unconventional reservoirs
  • Anisotropy of shales
  • Rock physics modeling of kerogen in organic-rich shales
  • Effect of anisotropy on AVO
  • Microseismic and effect of azimuthal anisotropy on propagation of hydraulic fractures

 

Seismic Acquisition and Processing

The overall objective of this course is to introduce entry level and/or junior Geophysicists and Geoscientists to the essential acquisition and technical processing concepts and principles that form the basis for value added seismic applications in exploration, field appraisal, and reservoir management. Learning objectives are at foundation and  knowledge levels.

Emphasis is on practical understanding of seismic acquisition and imaging. Data examples, exercises, and workshops are used to illustrate key concepts, practical issues, and pitfalls of acquisition and processing as they affect the interpretation and integration of seismic data and information into E&P workflows.

1

Module 1 – Introduction

Objectives –How seismic data assists today’s E&P - 2D vs 3D - Interpreting Seismic Data – Size of operations - Issues & Concerns

Module 2 – Basic Concepts of Seismic Surveying

What makes a seismic trace – Body & Surface waves - Reflection and refraction - Basics of seismic fold and image or stacked traces – Stacking Diagrams

Module 3 – Seismic Wave Propagation

Principles of wave propagation - Physical basis of wave types – Huygens‘s principle - Refractions and Diffractions - Seismic Velocities - Reflection amplitude, converted waves and AVO

Module 4 – Signal Analysis

Waves in time and space, Frequency and Wavenumber, Fourier analysis - Aliasing both spatial and temporal – FK transform - Convolution - Cross & Auto correlation.

2

Module 5 – Seismic Reflection Principles

Properties of Seismic Waveforms and traces – Polarity - Vertical Resolution – Lateral Resolution – Tuning - Amplitude Effects

Module 6 – Field Data Acquisition Principles

Types of Seismic Data Acquisition – Marine, Land, Transition, Borehole, Ocean Bottom, TimeLapse – Signal and Noise – Field Array Design – Alternatives to arrays – Common Reasons for Failure

Module 7 – Marine Acquisition Systems and Operations

Overall Layout – Towing Technology - Sources – Receivers – Benefits of Single sensor recording - Streamer Positioning – Narrow, Wide & Multi Azimuth - Over Under / DISCover – Slanted Cables - Gradient Measurements – Ocean Bottom Recording - Simultaneous Sources - Quality Assurance

Module 8– Land Acquisition Systems and Operations

Sources – Sensors – Positioning - Recording the Data – Arrays or Single Sensor Recording – Full Azimuth recording - Simultaneous Sources – Industry Trends Quality Assurance

3

Module 9 – Near-Surface Distortion Correction

Causes of Distortions – Seismic Datum – Long & short wavelength statics

- Surface Consistency - Methods of Correction – Identifying errors

Module 10 – Wavelets and Wavelet Shaping

Reasons why Wavelet Shaping is necessary – Types of wavelets – Zero & Minimum phase

- Types of Deconvolution - Decon.’s place in the sequence – Examples.

Module 11 – Regularization

The need for regularization – Types of methods used – Cautions - Examples

Module 12 – Noise Attenuation

Noise Types – Noise Removal Methodologies – Organised Noise – Radon Transforms

- Seismic Interference - Random Noise – Examples

Module 13 – Multiple Attenuation

What are multiples? – Types of multiple - Classifications and examples of removal methods

More (different) Radon Transforms – Data Examples

4

Module 14 Velocity Analysis for Time Processing

Types of velocity – NMO stretch – Velocity Analysis Techniques – Potential pitfalls

Module 15 – Velocity Model Building

Importance of velocity - Types of Model geometries – Tomography – Velocity model building techniques – Diving Wave, Tomographic, Complex Salt, Full Waveform Inversion, Multi Azimuth

Module 16 Imaging

Differences between Time and Depth Imaging – Limitations of Post stack imaging - Current Imaging Techniques - Their strengths and weaknesses - Examples – Likely future trends

Module 17 Imaging with Anisotropy

What is anisotropy? – How is it caused – Thomsen’s parameters – Different types of anisotropy – Rules of thumb - Examples

5

Module 18 – Survey Design

Survey Objectives – Geophysical & Processing Considerations

– 3D Surveying – CMP distribution – Binning – Critical Survey parameters

– Calculating their values - Survey Size Calculations – Migration Apertures – Artifacts and Footprints

Recap and Review

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

 

Land Seismic Acquisition Techniques and Survey Design

The course is designed to familiarize the student with the basics of 3D Land seismic acquisition before moving on to cover the more recent developments: high channel-count single sensor (point receiver) simultaneous source – high productivity vibroseis, broadband techniques (boosting the low and high freqencies) and wireless nodal systems. Learning is supported through numerous case histories that illustrate the value of each acquisition technique. Central to the success of these techniques is how the surveys are designed to deliver fit-for-purpose data in a cost-effective manner.

In the second half of the course the students are taken through the principles of survey design. Learning is supported via hands-on practice where participants work together to design solutions to typical survey objectives and challenges.

At the end of the course, students will be familiar with: all current and emerging land seismic acquisition technology and techniques; the principles and workflows employed to design land seismic surveys; how to make a “first-pass” assessment of whether a proposed survey design will be successful and economic; and how and what to recommend as further areas of investigation if required.

1

Land Seismic Acquisition Technology

  • Overview of course content & learning objectives
  • Introduction: operations and 3D acquisition geometries
  • Hi-channel count single sensor (point receiver)
  • Case study example: China integrated study
  • Exercise: operational efficiency (1)

Learning objectives: Understand the basics of land acquisition: operations in a variety of different terrains and environments. Understand the typical 3D land acquisition geometries, the motivations behind them, their limitations and how they can be expressed with different attributes and metrics. Understand the concept of single sensor and single source acquisition vs arrays, and the consequences for data processing. Understand the characteristics of ambient and coherent noise, the importance of coherent noise sampling and how it can be filtered.

2

Land Seismic Acquisition Technology

  • Simultaneous source, high-productivity vibroseis
  • Broadband
  • Wireless nodal systems
  • Case study example: single sensor broadband
  • Exercise: operational efficiency (2)

Learning objectives: Understand the cost benefit of simultaneous source acquisition, the different methodologies, how and when they can be used to deliver improved data quality and/or more efficient operations, and the implications for data processing. Understand how broadband data improves resolution. Understand the importance of low frequencies and how they can be obtained in the field. Get an overview of wireless nodal systems and their impact on acquisition operations. Understand how to analyze operational efficiency and its parameters.

3

Survey Design Basics

  • Survey design basics
  • Modeling, using a 1D earth model, to determine offset/angle limits, muting, bin size, fold and migration aperture
  • Exercise: resolution spreadsheet

Learning objectives: Understand the basic objectives and methods of land survey design. Understand how to use existing data and what constitutes a viable earth model for 1D seismic modeling. Understand the different types of resolution in seismic data required for successful interpretation and reservoir characterization. Understand how to determine basic acquisition parameters using a few simple equations starting from a 1D earth model.

4

Survey Design - Designing a 3D geometry

  • Designing a 3D geometry
  • Survey design impact on imaging
  • Case study example: UAE integrated study
  • Exercise: generate a 3D acquisition geometry

Learning objectives: Understand how to translate basic survey design parameters and objectives into a 3D acquisition geometry and how to choose between the different geometry options.  Understand the relationship between acquisition geometry and modern time and depth imaging workflows.

5

Survey Design - New processing technology & Inversion

  • New processing technology: noise attenuation, demultiple, surface wave inversion, interpolation, irregular geometries
  • Survey design impact on inversion (AVO, pre-stack, AVOAz)
  • Case study example: inversion for unconventionals (US)
  • Review of course objectives and feedback

Learning objectives: Understand the requirements for critical processing steps like demultiple, how new interpolation technology can impact survey design and how new processing technology enables non-uniform survey layout. Understand the requirements that AVO, pre-stack inversion and AVOAz (fractures & stress) place on survey design.

Deepwater Seismic Interpretation

This course addresses the problem of accurate seismic interpretation in deep-water and the delicate construction of seismic maps in the deep-water realm. It is intended to all petroleum professionals involved in exploration and production, geophysicists, geologists, rock physicists, reservoir engineers and drilling engineers.

Seismic interpretation is covered with a series of practical examples that focuses on the deepwater realm, with emphasis on proximal, intermediate and distal marine reservoirs. Acquisition and processing of 2D and 3D data is also discussed in what concerns the practical use of the rather extensive growing database libraries in deepwater.

The distinct data challenges in deepwater are examined in detail so that it would lead to practical problem of drilling locations and the finding and development of deepwater deposits.. Issues in the drilling of deep-water wells such as thickness of the overburden, pore-pressure prediction and geo-steering, are discussed. Practical workshops involve understanding of the main techniques in the seismic section interpretation and in precise structural contouring mapping in deep-water, with focus on the continental slope bathymetry correction and its effect upon time and depth maps. Handling of seismic velocities, depth conversion, comparisons of 2D vs. 3D data, and the principles of 4D and of 4C seismology are also briefly discussed. Time-slice of 3D datasets, seismic interpretation of attributes of amplitude and phase are applied to the mapping exercises for the purpose of better reservoir characterization and possible occurrence of fluid effects.

COURSE OBJECTIVES are the practical understanding of aspects concerning the precise deep-water seismic interpretation fundamental for successfully drilling oil and gas wells in the deep-water realm. Correct estimates of seismic velocities and map contouring techniques in deep-water are essential for achieving ideal vertical and deviated well locations and to the geo-steering of horizontal wells upon reservoir development.

The course covers the essentials of offshore seismic data from acquisition to processing and interpretation. To this effect it examines seismic tape formats, data libraries, design of seismic proprietary and spec surveys, data processing workflows in deepwater and the utilization of interpretation software in workstations Methodologies for correct interpretation of seismic sections and the techniques applied in the architecture details of map contouring are discussed in connection with suites of exercises that apply these techniques in offshore data of passive and compressive continental margins, covering the outer shelf, slope, rise and basin.

Focus is given to the interpretation of deep-water reservoirs, mainly proximal, intermediate and distal turbidites. The main differences between hand-drawn interpretation and computer workstation mapping are discussed so that the principles of interpretation may be utilized to quality control computer section interpretation and computer mapping. This is particularly important in deep-water due to the effect of bathymetry over contouring and depth conversion.

Comparisons between hand contouring and computer contouring are carried out for the purpose of understanding the subtleties of subjective hand contouring versus grid algorithm contouring. Special emphasis is therefore given to hand contouring map interpretation comparisons with modern workstation software grid interpretation mapping for 2D and 3D data sets. Comparative interpretation of the main prospective deep-water regions of the world such as Gulf of Mexico, Offshore Brazil, West Africa, North Sea and Southeast Asia are effected with suite of comprehensive exercises covering structural and stratigraphic interpretation and the use of seismic attributes. Rift and compressional mapping exercises cover normal and reverse faults handling, the understanding of paleo-lows and paleo-highs and flattening of bathymetry for re-construction of basin tectonism. Handling of seismic velocities in deep-water are made with specific exercises of depth conversion. Attendees are daily given hands-on mapping problems and exercises that cover geophysical exploration and development mapping in deep-water. Salt tectonics models over distinct basins are examined and comparisons made for basin architectures and hydrocarbon plays of autochthonous salt vs allochtonous salt.

1

Deep-Water Seismology.

Seismic Interpretation Concepts.

History of the Seismic Reflection Method.

Reflection & Refraction, Wave Equations, Poisson’s Ratio. Wavelets, Convolution, Synthetic Seismograms.

Amplitude and Phase Spectrum - Deconvolution.

Seismic Acquisition and Processing Workflows.

Deep-Water Petroleum Geology Provinces and World Distribution of Deep-Water Basins.

Exploration and Production in Deep-Water.

Deep-Water Seismic Reflection Section Parameters 2D and 3D.

Un-migrated and Migrated Deep-water Seismic Sections and Dip and Strike Sections in the Deep-water Realm.

Seismic Ties, Time Maps. Four-Way Dip Closures, Fault Closures- Exercises.

Structural Interpretation in Deep-Water - Examples.

Seismic Stratigraphic Mapping in Deep and Ultra deep-water. Onlaps/Toplaps/Downlaps/Offlaps - Exercise.

Sands and Carbonates Reservoirs Stratigraphy. Deep-Water Reservoirs Stratigraphy - Turbidites.

Well Location and DrillMap Exercise.

Bright-spots - Dim-spots - Flat-spots. Seismic Attribute Analyses.

AVO – Amplitude Variation with Offset Evaluations

2

Deep-Water Mapping Techniques.

Map contouring exercises - anticline, rift basin, compressional basin.

Interpretation of deep-water records offshore rifted margins.

Data Comparisons: Gulf of Mexico, Offshore Brazil and West Africa, North Sea, Australia Northern Shelf/Slope, Southeast Asia Timor and Arafura Seas, Andaman Sea.

Mapping Exercise #1: Top and Base Salt Mapping in deepwater. Pull-up correction base salt. Bathymetry correction. Mapping Techniques - Discussion. Time and Depth Map Contouring in deepwater.

Mapping Exercise #2: Syn-Rift Isopach Mapping. Seismic Velocities: Average, Interval, NMO, RMS, Dix Equation.

Depth Conversion Techniques: PSTM and PSDM.

Gas seeps and gas hydrates recognition. Overpressure prediction

3

Deep-Water Reservoirs Interpretation Techniques.

Mapping reservoir porosity, net to gross and net pay thickness.

Reservoir identification - bright spots, dim-spots, flat-spots.

Attributes: amplitude, frequency and phase, windowed attributes.

Comparative Interpretation of Post-Stack & Pre-Stack Time Migration.

Pre-Stack Depth Migration - Interpretation.

Mapping Exercise #3: Turbidite Play Offshore Brazil. Mapping Techniques Precision.

Map Contouring - Block Faulting.

Deepwater Petroleum Systems: Source Rock Burial, Migration Paths, Trap Formation, Hydrocarbon Emplacement.

Prospect Generation ; Risking of Deep-Water Prospects ; Project Economics.

4

Deep-Water Compression Tectonics - Mapping Interpretation.

Southeast Asia: Makassar Strait, South Irian Jaya, South China Sea, Palawan Basin, West Natuna Sea.

Mapping Exercise #4: Southeast Asia Deep-Water Reservoirs.

Fault Contouring. Discussion of Mapping Techniques.

Velocities and Depth Conversion in deep-water.

Wells Location and Depth Map Construction.

5

Course and Projects Review.

Course Test(s).

Case Histories – GoM, West Africa, East Brazil, North Sea, Asia .

Course Review – Thematic discussion, topics, questions, answers.

Final Test.

Practical Depth Conversion with Petrel

Depth conversion (domain conversion) of seismic time interpretations and data is a basic skill set for interpreters. However, there is no single methodology that is optimal for all cases since the available seismic and geologic control varies in quantity and quality within each project. To design an effective approach to depth conversion, the first part of this course prioritizes understanding the nature of velocity fields and practical approaches to velocity representation. Next, appropriate depth-conversion methods are presented in case history and exercise form. Single-layer and more sophisticated multi-layer approaches are reviewed, along with depth-error analysis and the impact on formation top prognoses and volumetrics.

Depth conversion must also embrace the process of database validation. Poorly positioned wells, miscorrelated horizons, and inconsistent formation tops can introduce distortions in the implied velocity field and result in false structuring. Database validation is addressed via the formation of synthetic seismograms to confirm horizons correlation and the formation of basic Seismic Time vs. Formation Top QCs.

Prestack depth migration is now commonplace, and there is always the need to calibrate the depth volumes with well control. The basic QCs and methods used for depth conversion will also be applied to validating the ties between the formation tops and the surfaces used for calibration. This is particularly important during anisotropic depth migration where inconsistencies between well control and the seismic interpretation impact the estimation of anisotropic parameters, resulting in a compromised depth image.

This course emphasizes the formation of velocity models consistent with the well control. This is in context to creating Petrel Models suitable for reservoir simulation employing depth-calibrated inversion and other attribute cubes precisely integrated with the well information.

1

Module 1:  Overview of Depth Conversion

* Learning Objectives and Importance:    

  • Discuss goals for vertical time-to-depth conversion

* Topics:          

  • Accuracies needed for  relative structure, well prognoses, volumetric estimates, and reservoir models
  • Database validation
  • Indicators for prestack depth migration (PSDM)

* Exercises:  Discussions on student goals and experiences with time-to-depth conversion

 

Module 2:  Sources of Velocity

* Learning Objectives and Importance:    

  • Review sources of velocity information

* Topics:          

  • Sonic logs, check shots, and VSPs
  • Seismic (refraction, reflection)
  • Inversion

* Exercises:  Analysis of various velocity data types

 

Module 3:  Defining Velocity Types

* Learning Objectives and Importance:    

  • Review definitions and characteristics of velocities

* Topics:          

  • Types of velocities
  • Conversion of velocity types
  • Compactional and layered geologies
  • Velocity gradients

 * Exercises:  Various problems on relating velocity types and conversions. Petrel exercises.

                           

Module 4A:  Functional Representation of Velocities

* Learning Objectives and Importance:    

  • Define velocities fields using vertical functions

* Topics:          

  • Velocity as a function of time and depth
  • Implicit velocity representation via T-D functions
  • Petrel Velocity Models with time and depth functions

* Exercises:  Various problems defining velocity fields in various domains

2

Module 4B:  Gridded Representation of Velocities

* Learning Objectives and Importance:    

  • Define velocities fields using grids

* Topics:          

  • Spatial velocity variations (lateral gradients)
  • Creating an edited PSTM velocity model in Petrel

* Exercises:  Import SEG Y velocities to Petrel and forming a gridded model

 

Module 5:  Well and Seismic Data Integration

* Learning Objectives and Importance:    

  • Understand methods for linking well and seismic information in Petrel

* Topics:          

  • Sonic and density log editing
  • Checkshot loading
  • Establishing seismic data polarity and phase
  • Database validation and QCs
  • Creating synthetic ties

* Exercises:  Problem sets and interactive work sessions

3

Module 6:  Vertical Time-to-Depth Conversion (Single Layer)

* Learning Objectives and Importance:    

  • Implement basic depth conversion using T/Z functions and/or Petrel Velocity Models

* Topics:          

  • Simple, intuitive depth conversion (no velocity model)
  • QC methods that define Time Depth Relationships (TDRs)
  • Basic Petrel Velocity Models

 * Exercises:  Problem sets and interactive work sessions

 

Module 7:  Vertical Time-to-Depth Conversion (Multi-Layer)

* Learning Objectives and Importance:

  • Explore advanced depth conversion with layer-based Petrel Velocity Models

* Topics:

  • Geologic and data-driven modeling considerations
  • Multi-layer options
  • “Simple” thrust models
  • Advanced Petrel Velocity Models

* Exercises:  Problem sets and interactive work sessions

4

Module 8:  Well/Seismic Database Validation

* Learning Objectives and Importance:    

  • Appreciate the need to review and correct the database prior to  incorporating well control

* Topics:          

  • Confirm database settings
  • Review seismic data polarity, phase, and synthetic correlations
  • Using basic depth-conversion QCs to encounter data discrepancies

* Exercises:  Extensive exercises on detecting and correcting errors and inconsistencies in the database

 

Module 9: Petrel Models and Uncertainty Analysis

* Learning Objectives and Importance:    

  • Implement domain conversion and uncertainty analysis with Petrel Velocity and 3D Models

* Topics:          

  • Evaluating depth uncertainty
    • Mean and standard deviation workflow (new)
    • Hidden well workflow
    • Stochastic velocity modeling
  • Impact of structural uncertainty on volumetrics in 3D Models

* Exercises:  Various Petrel exercises

 

Module 10:  Pitfalls of Vertical Depth Conversion

* Learning Objectives and Importance: 

  • Understand accuracy of vertical time-to-depth methods and when they fail

* Topics:          

  • QCs and validity of vertical depth conversion
  • Extreme geologic regimes
  • Alternatives to vertical depth conversion

* Exercises:  Problem sets and interactive work sessions

5

Module 11:  Anisotropy and Depth Migration

* Learning Objectives and Importance:    

  • Appreciate the impact of anisotropy on seismic velocities and depth imaging

* Topics:          

  • Seismic anisotropy
  • Parameterizing anisotropy (Vz, delta, epsilon, VTI/TTI)
  • Industry approaches to anisotropic prestack depth migration (APSDM)
  • Problems and promise of anisotropy for velocity definition and reservoir attributes

* Exercises:  Discuss impact of anisotropy on depth conversion and imaging

 

Module 12:  Calibration of Depth Migration with Wells

* Learning Objectives and Importance:    

  • Learn basic approach for stable integration of depth-domain seismic (PSDM) with well control

* Topics:          

  • Working in the time domain
  • Updating the time/velocity model
  • Conversion of time data to calibrated depth
  • Optional: Map migration for dynamic calibration and uncertainty

* Exercises:  Various Petrel calibration exercises

 

Practical Seismic Attributes with Petrel

In this course the students learn the theory and practical workflows needed for effectively using post stack seismic attributes in seismic interpretation.

The course content covers the most common seismic attributes, discusses the theory, attribute management and visualization. It delivers concepts and workflows for the interpretation of stratigraphy, structure, direct hydrocarbon indicators and discusses clastic, carbonate and reservoir features. 

The students learn these concepts and workflows while guided by well-structured exercises done in Petrel and based on a variety of seismic datasets.

This course will outline the practical aspects of generating and understanding Seismic Attribute responses and relating these from the mathematical geophysical generation to practical geological understanding and application.

Focus will be placed on outlining the use of seismic attributes in specific geological environments and identification of specific geological features.

The Learning Objectives for the course are

  • Teach the theory of seismic attributes
  • Teach the practice of seismic attributes using example sessions with Petrel software
  • Prepare you to use seismic attributes in your work

 

1

  • Short History and Theory of Seismic Attributes
  • Seismic Attributes in Petrel
  • Colors and Visualization of Attributes
  • Surface Attributes in Petrel
  • Noise Reduction
  • Fault Interpretation (Edge Detection)
  • Fault Interpretation (Edge Enhancement)

During the first part of the day the students learn the basic theory and concepts of seismic attributes. Different visualization techniques are covered using Petrel including color and opacity management and co-rendering of different seismic attributes (RGB display mode).

During the second part of the day the students learn using seismic attributes for noise reduction and the workflow for fault interpretation based on a combination of seismic attributes. The resultant cube highlights faults against the seismic background dramatically and is ready to be used for accurate manual or automated interpretation.

2

  • Stratigraphic Interpretation
  • Channel Interpretation
  • Textural attributes
  • Fracture indicators

On day two the students learn to use seismic attributes to highlight stratigraphic terminations and sequence boundaries and apply them on a data set to perform the seismic stratigraphic interpretation.

After this the students learn to apply seismic attributes and techniques to highlight channels and sedimentary features in clastic sedimentary environments and their interpretation using probes and geobodies.

Then the students learn how to use textural seismic attributes to separate sedimentary features based on their texture.

Finally the students review some of the attributes commonly used for fracture detection.             

3

  • Carbonates
  • Salt
  • Direct Hydrocarbon Indicators (DHI)
  • Seismic calculator
  • Group project

During this day the students review the seismic attributes and techniques used for Carbonate seismic interpretation with emphasis on karst features.  It follows a review of the seismic attributes and techniques to highlight salt features and their interpretation.

Then the students review some seismic attributes commonly used as direct hydrocarbon indicators. They will use the seismic calculator to highlight features in their seismic data, merge seismic volumes and create new seismic attributes.

The day concludes with a group project where the students   use the concepts they learned during the course to perform an interpretation challenge based on a seismic data set.         

Borehole Seismic Technology

Borehole Seismic data provides the critical depth and velocity parameters needed to link seismic data with downhole log and well data.

Borehole seismic tools have evolved from single-component sensors to modern seismic arrays. These moden tools, when combined with the latest technology in seismic source quality, navigational positioning, and computational abilities, can deliver in real time high-resolution borehole seismic images that extend beyond the wellbore or into the interwell volume to reduce risk in drilling and development decisions

This course provides a review of the latest tools, technologies, and applications of borehole seismic technology. A discussion of survery design and modeling is also included. This will provide an understanding of the applications of Borehole Seismic Data to Exploration, Reservoir Description, and Production.

1

Geophysical Principles

The seismic method-seismic response-basic concepts-reflection and refraction-velocity-seismogram -borehole vs surface seismic-types of borehole seismic.

Sources and Tools

Impulsive Sources (Airguns) - control systems - Non-impulsive sources (Vibros). Borehole seismic tools, classifications, characteristics - CSI and VSI

2

Checkshot Sonic Calibration and Well Tie

Velocities - The Sonic Tool - Sonic Scanner - Checkshot Survey - Drift - Sonic Calibration and Synthetic Seismogram

VSP Processing

Multiples - Processing Sequence - Stacking, Normalization & Filtering - Upgoing and Downgoing Energy - Deconvolution - Corridor Stack

3

VSP Processing - Anisotropy and AVO

Phase Matching - estimation of Q-Factor - concepts of anisotropy - Thomsen Parameters - AVO calibration - parameters from walkaway and walkaround VSP - parameters from other sources

VSP Imaging

Offset VSP coverage - Data Processing - NMO/CDP mapping - GRT migration - Walkaway VSP coverage - VSP in deviated wells - 2D and 3D VSP

4

Survey Design and Modeling

Practical and theoretical modeling concerns - basic modeling - ray tracing modeling

Reservoir, Production, and Drilling Applications

Salt proximity surveys - Aplanatic method - Deeplook CS - Time-Lapse BHS surveys - single well survey - seismic while drilling (SWD) - Look-ahead VSP - Borehole Microseismic surveys

5

Examples

Exercises

Case Histories

 

highlights

Mini Master of Art Degrees in Political Science Mini Master of Art Degrees... A Mini Master of Arts in Political Science gives students the...
Mini Masters Programs in International Management Mini Masters Programs... Students pursuing an advanced degree in international management...
Mini Masters Programs in Humanities Studies Mini Masters Programs... A Mini Master in Humanities is a field of study that includes...