Principles of 3-D Seismic Interpretation
Course Instructor: Mangat R. Thapar, Ph.D.
Who should attend?
Interpreters who need an understanding of 3-D seismic interpretation fundamentals, geophysicists, geologists, technical support personnel, seismic processors, data processing and acquisition supervisors and managers. This course will benefit any geoscience professional who utilizes 3-D seismic data.
Prerequisites:
It is recommended that participants take Seismic Survey Design, Acquisition, and Processing, and AVO and Seismic Attributes, or equivalent courses.
Course Description:
Costing less than a few pennies per barrel of oil, 3-D seismic surveys can be extremely prudent investments. 3-D seismic data not only reduces the risk of drilling exploration and development wells, but also can dramatically increase production from existing fields. The success of any exploration or development program, utilizing 3-D seismic data, is dependent upon accurate, three-dimensionally viable interpretations of the seismic data. The successful application of a 3-D seismic survey depends on the following principles of proper design, acquisition, processing, guarding against pitfalls, and utilization of available 3-D technologies for accurate and three dimensionally valid structural and stratigraphic interpretations. This course covers the following fundamental seismic principles:
(1) A detailed step by step discussion of how to design a 3-D survey along with crucial processing steps and related pitfalls
(2) A discussion of the application of VSP, methodology for mapping channels, Geostatistical Krigging for thickness interpolation, time lapse 3-D (4-D), principles of P & S wave (multi-component) anisotropy analysis and interpretation, component rotation, and S-wave splitting into slow and fast due to fractures and saturation.
(3) In-depth explanation of thin bed thickness estimation using properly processed and modeled amplitudes and frequencies, and related pitfalls.
(4) How to utilize of seismic attributes including coherency and variance?
(5) How to apply seismic modeling in 3-D analysis and to convert stacking into interval velocities for dipping layers?
(6) A detailed step by step procedure for structural interpretation is presented. In this section of the course, we use a live demonstration of principles of 3-D design (using OMNI), analysis and interpretation (using Geographix – Discovery).
(7) Procedures for stratigraphic interpretation are presented with examples and exercises.
(8) How to conduct the risk analysis of 4-D seismic, reviewing more than 20 case histories from many parts of the world.
Exercises
Exercises are conducted throughout the course to enhance the understanding of principles presented. Some of these exercises include:
(a) Designing a 3-D survey over a prospect.
(b) Mapping reservoir thickness from seismic amplitudes, recognize and overcome a very important pitfall.
(c) Several exercises for mapping faults and reservoirs to estimate oil and gas resources or reserves.
(d) The mapping of channels in the presence of structure using in-lines, cross-lines and horizontal slices.
(e) Reservoir management and 4-D exercise to estimate the life of the field and time lapse, and design 4-D parameters.
(f) Group discussion and analysis exercise to systematically review and evaluate more than twenty 3-D case histories
Course Content
· Overview of 3-D data acquisition and processing
· Principles of 3-D migration
· Horizontal and horizon slices
· 3-D modeling
· 3-D seismic technologies
· Reduced risk using 4-D
· Successful applications of 3-D in E&P
· Geostistical Kriging and variogram
· Anisotropy, 3-D, 3-C, S-waves
· Principles of structural & stratigraphic Interpretation
· Application of seismic attributes
· Thickness estimation using amplitude modeling, and frequency
· Reservoir management using 3-D
· Summary of 3-D seismic case histories from around the world
Participants will learn how to:
• Utilize essential procedures in structural and stratigraphic interpretation
• Apply fundamental principles of structural and stratigraphic interpretation
• Use Geostatistical Kriging
• Use S-waves in fractured reservoir interpretation
• Estimate thin bed thickness with 3-D data
• Make use of reservoir characterization and compartmentalization tools
• Conduct risk analysis of 4-D data
Participants are encouraged to bring data examples related to this course.
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Chapter 1 |
Chapter 2 |
Chapter 3 |
Chapter 4 |
Chapter 5 |
Chapter 6 |
|
Chapter 7 |
Chapter 8 |
Chapter 9 |
Chapter 10 |
Chapter 11 |
Exercises |
3-D Seismic
Chapter 1 : Introduction and Overview of 3-D
Calculation of Fresnel Radius
Velocity – Frequency – Wavelength Relationship
Impact of Fresnel Zone Concept of Seismic Reflections
Data Processing Flow for 3-D Seismic
3-D Data Acquisition
Types of 3-D Surveys:
Directional 3-D Surveys
True 3-D Surveys
3-D Data Processing
Initial or Pre-Processing
3-D Velocity Analysis
Important Requirements for a 3-D Velocity Analysis
Multi-parameter Velocity Analysis
Statics Estimation and Correction in 3-D
Factors Affecting Seismic Amplitude in 3-D
Reflection and Transmission Loss
Spherical Divergence
Attenuation
Total Amplitude Decay
Stacking in 3-D
Common Midpoint Stacking
Common Reflection Point Stacking
Migration in 3-D
Full 3-D Migration:
2-Step 3-D Migration Process:
2-Step 3-D Cascading Migration Process:
Forward Modeling
Inverse Modeling
Seismic Migration - Inverse Modeling
Post Stack Migration
Pre-Stack Migration
Volume Displays of 3-D Data
Benefit of 3-D Seismic Coverage Over 2-D Seismic
Horizontal Slices
Surface Map (Courtesy of Geoquest)
Horizon and Fault Surface Slice (Courtesy of Geoquest)
Chapter 2 : Survey Planning and Design
Review Historical Data for Geology and Geophysics
Survey Design Objective and Planning
Data Acquisition Configurations
Problems and Difficulties in Survey Design
3-D Survey Design and Analysis
Fundamentals of 3-D Seismic Surveys
Fresnel Zone as Applied to Seismic Reflections and Migration.
Major Steps in Designing 3-D Surveys
Survey Design to Meet Processing Objectives
Template Design: Number and Length of Receiver Lines
Swath Surveys
Full 3-D Surveys
Loop Surveys
Circular Surveys
Parallel Surveys
Checkerboard Survey
Marine Surveys
Random Source and Receiver Surveys
Transition Zone Surveys
Full or Dense 3-D
Swath
Orthogonal
Non-Orthogonal
Brick
Flexibin or Bin Fractionation
Button Patch or Checkerboard
Zig-zag
Mirror Image Zig-zag
Double Zig-zag
Megabin
Star
Radial
Circular Patch
Random Source-Receiver Layout
Aerial Coverage
Shooting Dip/Strike
Bin Size and Fold
Source Interval and Source Line Spacing
Receiver Interval and Receiver Line Spacing
Template Movement
Estimating Number of Moves for a Template:
Attribute Analysis
Recording Equipment, Seismic Crew and Cost
Designing a 3-D Survey Example
Case Histories
Parallel Swath 3-D Survey
Marine-Transition-Land 3-D Survey
Chapter 3 : Seismic Technology
Technology Developments
VSP and Sonic Logs
Stratigraphic Cross-Sections
Pressure History from Wells
Seismic Sequence Stratigraphy
Seismic Sedimentology
Seismic Facies
Pattern Recognition
Structure and Faulting
Channels
Reservoir Characterization
Geostatistical Kriging
Modeling Variogram
Object Oriented Modeling
Technology Developments
Seismic Amplitudes in 3-D Surveys
Factors Affecting Seismic Amplitudes
Types of Amplitude Anomalies
Bright-Spot
Dim-Spot
Amplitude Alignment
Amplitude Horizontal Slices
Amplitude Horizon Maps
Reservoir Properties
Amplitude and Structure
Amplitude and Lithology
Time Lapse Reservoir Monitoring Using 4-D Seismic Surveys
Fundamental Requirements of 4-D Seismic Surveys:
Comparison of 3-D Surveys:
Time Lapse 3-D or 4-D Surveys
Principles of Multicomponent Seismic
Polarization
Anisotropy
Inherent
Induced
Long Wavelength
Azimuthal
Transverse Isotropy
S-Wave Splitting
Multicomponent Acquisition
Important Factors in Multicomponent Data Acquisition
Multi-Component Seismic Data Processing
Component Rotation
Separation of S-Wave Components
P-S NMO Correction
Velocity Analysis and Muting
Common (P-S) Conversion Point Binning
Statics
Processing Flow
Post-Stack Residual Rotation
Principles of Interpretation and Applications
Rock Properties from 3-Component Data
Seismic Processing Onboard Marine Vessels
3-D Depth Imaging
Workstation Technology
Chapter 4 : Thickness Estimation from Amplitudes
Thick Layers
RMS and Stacking Velocities
Tuning Amplitude
Constructive Interference
Procedure for Thickness Estimation of Thin Beds
Thickness Estimation using Dominant Frequency
Wavelet Processing
Amplitude and ΔT Values
Thickness from Amplitude and ΔT
Calculating Amplitude Response Curve
Frequency
Dominant Frequency and Dominant Amplitude
Discrete Frequency Components
Notches in Frequency Spectrum
3-D Frequency Volume
Thickness Calculation from Frequency Components
Wavelet Character Variation
Frequency Content and Notches
Velocity Decrease or Increase
Effect of DC Bias on Spectrum
Chapter 5 : Application of Seismic Attributes
Application of Seismic Attributes to 3-D Seismic Data
Classification of Seismic Attributes
Seismic Attributes and Reservoir Rock Properties
Complex Trace
Amplitude Based
Energy
Frequency
Phase
Polarity Based Attributes
Acoustic Inversion
Coherency Based Attributes
Seismic Attributes and Wave Propagation
Seismic Attributes Used for Reservoir Rock Properties
Seismic Amplitude
Coherency or Semblance
Variance
Application of Variance
Variance and Coherence
Amplitude Based
Energy Based
Amplitude and Polarity Weighted
Volume Visualization and Voxels
Voxel Trace
Opacity Representation and Editor
Visualization Procedure
Visualization & Interpretation
Stratigraphic Visualization
Structural Visualization
Pitfalls
Important Points
Autopicking or Autotracking of Reflector Surfaces
Voxel Tracking
Surface Slicing
Stratigraphic Interpretation
Attributes and Seismic Data
Chapter 6 : Seismic Modeling (3-D)
Factors Affecting Seismic Wave Propagation
Factors Affecting Velocity
Factors Affecting Frequency
Factors Affecting Phase
1-D Seismic Modeling
Seismic Wavelet
Synthetic from Sonic Log
Synthetic and Seismic Comparison
2-D Seismic Modeling
Geometry
Elastic Parameters
Seismic Wavelet
Synthetic Traces
Raytracing and Reflection Coefficient Series
Wavelet
Applications of 2-D Modeling
Normal Incident Ray
Vertical Incident Ray
Oblique Incident Ray
3-D Seismic Modeling
Elastic Parameters
Seismic Wavelet
Applications of Modeling
Inverse Modeling: Downward Continuation Method
RMS and Interval Velocities
RMS and Stacking Velocities
Time to Depth Conversion
Following are the Assumptions in this Analysis:
Real Data Example
Use of Seismic Modeling in 3-D Data Processing
Velocity Analysis
Binning and Stacking
Time Migration
Inverse Modeling Time Maps to Depth
Map Migration
Seismic Modeling in 3-D Data Interpretation
3-D Seismic Modeling in 3-D Depth Migration
Gridding Techniques
Triangulation
Triangulation Examples
Inverse Distance Interpolation
Directional Weighting
Trend Surface Polynomial and Residuals
Steps in Contouring Seismic Data
Chapter 7 : 3-D Structural Interpretation
3-D Interpretation
Structural Interpretation Steps
Fault Detection and Interpretation
Estimating Fault Throw
Fault Polygon or Gap
Interpret and Pick Faults
Interpret Horizons
Draw Fault Polygon
Structural Maps
Time Maps
Depth Maps
Time Interval Maps
Thickness Maps
Dip Maps
Coherency Maps
Volumetric Analysis or Reservoir Evaluation
Material Balance
Seismic Sections
Constant Time Slices or Structure and Slicing
Constant Time Slices and Seismic Data
Horizon Surface Slices and Seismic Data
Recognition of Structures and Features on Horizontal Slices
Anticlinal Structures
Synclinal Structures
Recognition of Structure and Faults on Horizontal Slices
Faulted Anticlinal Structures
Contouring from Seismic Slices
Structural Relationships between Structures and Faults
Structure Contour Maps Using Vertical Sections
Structure Contour Maps Using Horizontal Slices
Fault Mapping and Interpretation
Composite Displays of 3-D Data
Interpretation Steps
Subtle Features
Recognition of Salt Domes on Horizontal Slices
Chapter 8 : 3-D Stratigraphic Interpretation
Stratigraphic Features
3-D Tools
3-D Requirements for Stratigraphic Analysis
Interpretation of Stratigraphic Features Using Horizontal Slices
Resolution and Aerial Extent
Structure and Deposition
Features Recognition
Depositional Surface from Horizontal Slices
Mapping Channels
Horizon Slice
Methods of Horizon Slice
Poor Reflection Zone
Horizon Slice Attributes
Horizon Slice Benefits
West Texas 3-D Data
Stratigraphic Column of West Texas
Horizontal Slices over Producing Interval
Horizontal Slices (800 – 890 ms)
800 – 810 ms
820 – 850 ms
860 – 890 ms
Horizon Slices using Peaks and Troughs
Time Slices and Coherency Slices
Stratigraphic and Similarity Maps
Stratigraphic Maps
Similarity Maps
Stratigraphic Maps
Time Window for Stratigraphic Mapping
Different Pilot Traces
Number of Pilot Traces
Decreasing Window Length
Time Window
Well Defined Character
Dominant Event and Window Length
Stratigraphic and Similarity Maps
NE Colorado – Sooner Unit 3-D Data
Vertical Seismic Sections
D-Sand Overlays Contours
Horizontal Slices
Composite Displays
D-J Sands
Deltaic Pattern at Niobrara
Interpretation of Reefs on Horizontal Slices
Interpretation of Large Circular Atoll on Horizontal Slices
Interpretation of Unconformity
Angular Unconformity
Erosional Unconformity
Chapter 9 : Reservoir Management
Reservoir Management Using 3-D Seismic
Use of 3-D Seismic in Reservoir Management
Reservoir Geometry
Rock and Fluid Properties
Monitoring Flow
Reservoir Identification
Bright Spot Reflections
Processing:
Interpretation
Flat Spot
Seismic Attributes
Analysis
Dim Spot Reflections
Processing:
Interpretations:
Analysis:
Pitfalls of Bright and Dim Spots:
Cross-Plotting Thickness (Porosity) vs Amplitude
Compartmentalization of Reservoir
NE Colorado – Sooner Unit
Production and Reserves:
3-D Seismic
Reservoir Compartments
Field Redevelopment
Conclusions
Seismic factors in Compartmentalization
Fault Mapping on Vertical Sections
Fault Mapping on Horizontal Slices and Structure Maps
Lithlogic and Stratigraphic Changes
Reservoir Characterization
Chapter 10 : Successful Applications & Reduced Risk in E&P
Successful Applications of 3-D Seismic
Success of 3-D Seismic
Nigeria
Netherlands
Shell Companies
Exxon
Producing Fields Reactivated with 3-D Seismic
Reduced Risk in Exploration and Production
Some Important Observations:
Factors Affecting Value of 3-D Seismic
3-D Seismic and Drilling
Risk Assessment of 4-D Seismic
Raw Data for Reservoir and Seismic Properties
Depth:
Net Pressure:
Bubble Point:
Temperature:
Unit Thickness:
Dry Bulk Modulus:
Porosity:
GOR:
Salinity:
4-D Fluid Saturation Change:
4-D Fluid Compressibility Contrast:
Dominant Seismic Frequency:
Average Resolution:
Image Quality:
Repeatability:
Fluid Contact Visibility:
Travel-Time Change:
Impedance Change:
Assigning Scores
Scorecard
Guidelines for Seismic Scores
Quality of Seismic Data:
Seismic Data Resolution
Seismic Reflections from Fluid Contacts:
Seismic Repeatability:
Completing the 4-D Risk Assessment Spreadsheet
Interpreting Risk Assessment Spreadsheet
Reservoir Properties and Conditions:
Seismic Properties and Conditions:
Discussion:
Chapter 11 : 3-D Case Histories
(1) Interpretation of Fluvial Thin-Bed Reservoirs
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(2) Delineation of Thin Sandstone Reservoirs with Seismic Attributes
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(3) Imaging a Shallow Fluvial System
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(4) Effect of Seismic Interpretation on Reservoir Management
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(5) Structural and Stratigraphic Interpretation
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(6) Cost Effective Reservoir Delineation
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(7) Evaluation of Ping Hu Field
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(8) Impact on Development
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(9) Geophysical Reservoir Characterization
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(10) Seismic Modeling Using High Resolution Seismic Data
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(11) Reservoir Architecture
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(12) Facies Analysis
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(13) Seismic Attributes and Forward Modeling
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(14) Exploring for Pinnacle Reefs
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(15) Delineate Porous Carbonate Debris Flows
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(16) Reservoir Characterization with 3-D and 3-C Seismic Data
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(17) Reservoir Delineation and Characterization
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(18) Tectonics and Reef Development
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(19) Prediction of Reservoir Parameters
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(20) Reservoir Characterization and Development
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(21) Enhanced Oil Recovery
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(22) Quantitative Analysis of Seismic Reflections
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
(23) Structure of an Oil Field
Reservoir
3-D Seismic Data:
Interpretation:
Conclusions:
Exercises Table of Contents
Exercise 1: Frequency Aliasing
Exercise 2: Volume of 3-D Data to Display and View
Channel Detection
Exercise 3: Maximum Migration Aperture or Fresnel Radius
Exercise 4: Frequency vs Wavelength
Exercise 5: Forward Modeling
Inverse Modeling
Migration
Exercise 6: Surface Obstacles in 3-D data Acquisition
Exercise 7: Survey
Exercise 8: Fresnel Zone and Ray Tracing
Exercise 9: Survey Design
(1)Area Dimensions
(2)Bin Size
(3)No. of Shots per Square Kilometer
(4)Source Line Spacing
(5)Receivers and Receiver Lines
(6)Sources and Source Lines
(7)Total Fold
(8)Maximum Offset and number of Receivers/Line
(9)Template Moves
Exercise 10: P & S Wave Attenuation
Attenuation of P-Waves
Exercise 11: Bright and Dim Spots
Exercise 12: Multi-Component Recording
Exercise 13: Rock Properties
Exercise 14: Depth Imaging
Exercise 15: Time Lapse or 4-D Seismic
Exercise 16: Thin Beds-1
Exercise 17: Thin Beds-2
Exercise 18: Seismic Attributes
Exercise 19: Volume Visualization
Exercise 20: 3-D Modeling
Exercise 21: Horizontal Slices
Exercise 22: 3-D Survey
Exercise 23: 3-D Survey and Exploration Risk
Estimate Savings due to 3-D Survey
Risk Reduction
Exercise 24: 3-D Case Histories
Exercise 25: Thrust Model Horizontal Slices
Exercise 26: Gas and Oil Model Horizontal Slices
Exercise 27: Reservoir Management
Reservoir Compartmentalization
Wavelet Response Generated Slices for the Thrust Model
Spike Response Generated Slices for the Thrust Model
Wavelet Response Generated Slices for the Oil and Gas Model
Spike Response Generated Slices for the Oil and Gas Model
Exercise 28: 3-D Case Histories Review