Topic outline

  • Velocities

    This course provides an overview of all significant aspects and considerations of velocities for geoscientists and engineers, especially seismic interpreters, and anyone who needs to understand the basic theory and procedures for creating velocity models and converting seismic data from time to depth
    • Training Methodology & Objectives

      Training Methodology

      This Trainee-centered course includes the following training methodologies:-

      • Talking presentation Slides (PPT with audio)
      • Simulation & Animation
      • Exercises
      • Videos
      • Case Studies
      • Gamification (learning through games)
      • Quizzes, Pre-test & Post-test

      Course Objectives

      After completing the course, the employee will:-

      Apply and gain a comprehensive knowledge on velocities Discuss seismic velocities, principles, definitions, analysis and the basic concept of seismic exploration
      Describe the medium effects on waves, geometrical spreading, absorption and reflection/refraction Explain Snell’s law, reflection coefficients, magnitude, seismic events, seismic wavelet and seismic resolution
      Illustrate the model of a sedimentary rock, common calculation methods, seismic data acquisition and sonic well logging Recognize seismic sources, seismic recording systems, sources of noise, reference diagram for land static corrections and source of various components of static correction
      Examine the normal moveout equation and discuss the concept of constant velocity stack as an aid to stacking velocity estimation Demonstrate velocity spectra and identify the options in the promax velocity analysis routine
      Use promax routine velocity viewer and editor and recognize the common problem with stacking including the example of the data/velocity interleave display using landmark’s seiscube program Apply progressive mute analysis and methods of velocity-analysis as well as identify the factors controlling analysis locations and choose locations on a stacked section
      Carryout methods of velocity picking and interpolation, well velocity measurements, schematic cross section, corrections and sonic log integration Discuss interval velocity functions, well ties, instantaneous velocity, hybrid functions, average velocity function and geological effects
      Employ calibration, 3 parameter analysis, horizon velocity analysis, editing, filtering, smoothing, averaging and normalization
      • Course Description

        This E-Learning course is designed to provide participants with a detailed and up-to-date overview of velocities. It covers the seismic velocities, principles, definitions, analysis and the basic concept of seismic exploration; the medium effects on waves, geometrical spreading, absorption and reflection/refraction; the Snell’s law, reflection coefficients, magnitude, seismic events, seismic wavelet and seismic resolution; and the model of a sedimentary rock, common calculation methods, seismic data acquisition and sonic well logging
        Further, the course will also discuss the seismic sources, seismic recording systems, sources of noise, reference diagram for land static corrections and source of various components of static correction; the normal moveout equation and the concept of constant velocity stack as an aid to stacking velocity estimation; the velocity spectra and the options in the promax velocity analysis routine; the use of promax routine velocity viewer and editor; the common problem with stacking including the example of the data/velocity interleave display using landmark’s seiscube program; and the progressive mute analysis and methods of velocity-analysis
        During this course, participants will learn the factors controlling analysis locations and choosing locations on a stacked section; the methods of velocity picking and interpolation, well velocity measurements, schematic cross section, corrections and sonic log integration; the interval velocity functions, well ties, instantaneous velocity, hybrid functions, average velocity function and geological effects; and the calibration, 3-parameter analysis, horizon velocity analysis, editing, filtering, smoothing, averaging and normalization
        • Module 1 - Seismic Velocities

          Contents:
            • Basic Concept of Seismic Exploration
            • Video: Basic Concept of Seismic Exploration
            • Seismic Waves
            • Medium Effects On Waves
            • Reflection Coefficients
            • Time-Distance (T-X) Curves
            • Seismic Events - Primary Reflections
            • Seismic Events - Non-primary Events
            • The Seismic Wavelet
            • Seismic resolution
            • Seismic Resolution - Vertical
            • Velocity Porosity Relations
            • Seismic Velocity - Model of a Sedimentary Rock
            • Seismic Velocity - Porosity Relations
            • Porosity Relation With Density And Velocity
            • Seismic Velocity Types
            • Common Calculation Methods
            • Velocity Determination T-DTNMO method
            • Seismic Velocity - Uses of Velocity Data
            • Land Equipment
            • Recording
            • 2-D Field Methods - The CMP Method
            • T-X For A Single, Horizontal, Homogeneous Layer
            • Time-distance (T-X) Curves - Multiple Layers
            • Comparing Velocities
            • Estimation of VNMO
            • Vertical Seismic Profiling (VSP) Concept
            • Sonic Well Logging Tool
            • Non-Primary Linear Events
            • Module Quiz
          • Module 2 - Diffraction

            Contents:
              • Video: Wave Diffraction
              • Seismic Events - Non-primary Events
              • The Seismic Wavelet
              • Primary Reflections
              • 2-D Field Methods - The CMP Method
              • Velocity Determination - Hyperbolic-Fit Method
              • Relation Between True T-X Curve and RMS and Stacking Velocities
              • Velocity determination T-DTNMO Method
              • Gathers after Detailed Velocity Analysis
              • Gathers after Anisotropic Velocity Analysis
              • Module Quiz
            • Module 3 - Typical ProMax Flow For Velocity Analysis

              Contents:
                • A Typical Flow for 2D or 3D Velocity Analysis is:
                • Examining the Normal Moveout Equation, it is Possible to Analyze NMO Velocities by Plotting Reflections in T2 X2 Space
                • Concept of Constant Velocity Stack as an Aid to Stacking Velocity Estimation
                • One Method to Determine Stacking Velocity is to Use a Constant Velocity Stack (CVS) for Several CDP gathers
                • Same CVS Panel of Traces as Before Switching to Variable Density Color for the Traces to Utilize Dynamic Range
                • Another Term for Normal Moveout Equation
                • Options in the ProMax Velocity Analysis Routine
                • Demonstration of the Velocity Spectra
                • Options in the ProMax Velocity Analysis Routine
                • CDP Gather with NMO Applied (center) Surrounded by Panels Having Progressively Lower Velocity (Left) or Higher Velocity
                • The Semblance Panel shows the semblance plot, the picked velocity function, guide functions, and the interval velocity computed from the picked function.
                • Dix Equation Converts Stacking Velocities to Interval Velocities
                • Remaining Three Panels in Velocity Analysis Routine
                • A common problem with stacking is residual NMO on the CDP gathers resulting from imperfect velocity specification.
                • Example of the Data/Velocity Interleave Display Using Landmark’s SeisCube program.
                • Progressive Mute Analysis
                • Velocity Analysis
                • Difference Between CMP und CDP
                • Methods of Velocity-Analysis
                • x2-t2 - Analysis
                • Aim of Velocity Analysis
                • CMP Gathers with Strong Multiples
                • CMP Stack Using Former Gathers
                • Factors Affecting Velocity Estimates
                • Reflection Coefficients
                • Velocity Determination
                • Moveout
                • The Non-Hyperbolic T-X Curve of a Vertically Heterogeneous Medium
                • Compression Wave Velocity
                • The Seismic Anisotropy is the Dependence of Seismic Velocity Upon Angle
                • Module Quiz
              • Module 4 - Velocities

                Contents:
                  • Why is Velocity Important?
                  • Is It The Same Velocity In All Cases?
                  • So Where Do we Start?
                  • Average Velocity
                  • Interval Velocity
                  • RMS Velocity
                  • Interval Velocity of Layer Using the RMS Velocities
                  • Velocity Definitions
                  • Apparent Velocity
                  • NMO (Normal Moveout) Velocity
                  • Residual NMO
                  • Velocity; interval, nmo, stacking, rms, average
                  • NMO Stretch
                  • NMO Stretch - An Example
                  • Mute Definitions
                  • Stacking Velocity Increases With Dip
                  • Velocity Analysis
                  • Velocity Picking ; Omega 2 = INVA Interactive Velocity Analysis
                  • Semblance Analysis
                  • Velocity Analysis; MVFS; Multi Velocity Function Stacks
                  • Multi Velocity Function Stacks
                  • Constant Velocity Stack
                  • Constant Velocity Gathers
                  • Some Velocity Analysis Tools
                  • Multiples
                  • Water Bottom Multiples
                  • Peg Leg Multiples
                  • Factors Controlling Analysis Locations
                  • Choosing Locations on a Stacked Section
                  • Picked Velocity File
                  • Methods of Velocity Picking and Interpolation
                  • Velocity Inversions
                  • Q.C. of Velocity Field
                  • IVP ISO-Velocity Display
                  • Video: Velocity Analysis
                  • Module Quiz
                • Module 5 - Seismic Velocities & Depth Conversion

                  Contents:
                    • Seismic Velocities & Depth Conversion
                    • Introduction
                    • Travel Time Inversion
                    • Technology Usage
                    • Depth Conversion and Company Policy
                    • New Paradigm
                    • Macrovelocity
                    • The Macrovelocity Model
                    • Structural Sources
                    • Well Velocities
                    • Seismic Velocities
                    • Structural Detail
                    • Surfaces to Model
                    • The Macrovelocity Model
                    • Seismic Velocities
                    • Density of Well Velocity Data
                    • Velocity for T-Z Conversion
                    • Velocity Models
                    • Density of Well Velocity Data
                    • Velocity Definitions - 1
                    • Average Velocity VA
                    • Average Interval Velocity VI
                    • Instantaneous Velocity Vi
                    • Pseudo Velocity (Apparent, Effective)
                    • Root Mean Square (RMS) Velocity VRMS
                    • Summary
                    • Well Velocity
                    • Well Velocity Measurements
                    • Schematic Cross Section
                    • Velocities
                    • Source
                    • Near Surface
                    • Ray Paths - Zero Offset
                    • Well Velocity Curves
                    • Vertical Seismic Profile
                    • Geometry
                    • Records
                    • Velocities
                    • Walk Above VSP
                    • Corrections
                    • Sonic Log
                    • Tool
                    • BHC and LSS
                    • BHC Problems
                    • Long Spaced Sonic Log
                    • Full Waveform Sonic Log
                    • Shear Wave Logs
                    • Sonic Log Integration
                    • Discrepancies
                    • Absorption and Dispersion
                    • Sonic Log and Checkshots
                    • Drift Curve
                    • Dispersion
                    • Calibration
                    • Calibrated Sonic/Velocity Log
                    • Pseudo Velocity
                    • Datum
                    • Composite Reflections
                    • Depth
                    • Travel Time Error - AVO
                    • Travel Time Error - Position
                    • Travel Time Error - Stack
                    • Summary
                    • Video: Seismic time to depth conversion- Average velocity method
                    • Module Quiz
                  • Module 6 - Interval Velocity

                    Contents:
                      • Interval Velocity As a Function
                      • Constant
                      • Velocity as a Function
                      • Instantaneous Velocity as a Function
                      • Evjen’s Function
                      • The Error
                      • Instantaneous Velocity
                      • Hybrid Functions
                      • Instantaneous Velocity Functions
                      • Summary
                      • Average Velocity
                      • Interval Velocity
                      • Instantaneous Velocity
                      • Selecting the Best Function
                      • Extrapolation
                      • Constant Average Velocity
                      • Average Velocity Functions
                      • Instantaneous Velocity as a Function
                      • Sonic/Velocity Log Models
                      • Integration
                      • Sonic/Velocity Log Models
                      • Blocking
                      • Interval Velocity
                      • Time Average
                      • Wylie’s Time-Average Equation
                      • Depth Average
                      • Functions
                      • Instantaneous Velocity
                      • Slotnick
                      • Faust
                      • Evjen
                      • Functions
                      • Faust’s Function
                      • Extrapolation
                      • Functions
                      • Combining Logs
                      • Adding Seismic Velocities
                      • Tectonic Inversion
                      • Diagenesis
                      • Rate of Deposition
                      • Lithology
                      • Overpressure
                      • Blocking
                      • Functions
                      • Geological Effects
                      • Video: How to calculate the interval seismic velocity
                      • Module Quiz
                    • Module 7 - Velocity Definitions - 2

                      Contents:
                        • Root Mean Square (RMS) Velocity VRMS
                        • Heterogeneity Factor
                        • Moveout Velocity
                        • Moveout
                        • T2—X2 Plot
                        • Normal Moveout Velocity VNMO
                        • Normal Moveout
                        • Multiple Layers
                        • Taylor Series
                        • (RMS) Interval Velocity
                        • Long Offset
                        • Stacking Velocity Analysis
                        • Stacking Velocity in T2 – X2 Space
                        • Stacking Velocity for Our Model
                        • CMP Gathers
                        • Stacking Velocity
                        • Results
                        • Bias-B
                        • Interval Stacking Velocity VIS
                        • Average Stacking Velocity VAS
                        • Migration Velocity
                        • Refraction Velocity
                        • Summary
                        • Module Quiz
                      • Module 8 - Rays and Models - Raytrace Modelling

                        Contents:
                          • Seismic Velocity
                          • Refraction Analysis
                          • Basic Theory
                          • Picking
                          • More Theory
                          • Statics Software
                          • QC of picks
                          • Velocity Gradients
                          • Modelling
                          • Model Output
                          • Pitfalls
                          • Uphole Surveys
                          • Calibration
                          • Dip and Stacking Velocity
                          • 3 Parameter Analysis
                          • Stacking Velocity with DMO
                          • Prestack DMO
                          • Stacking Velocity with DMO
                          • Prestack DMO
                          • Prestack V(z) DMO
                          • Horizon Velocity Analysis
                          • Stacking Velocity Cube
                          • Interpolation
                          • Summary
                          • Stacking Velocity
                          • Errors in Stacking Velocity
                          • Near Surface Structure
                          • Moveout
                          • Refraction Velocity
                          • Near Surface Low Velocities
                          • Statics
                          • Stacking Velocity Distortion
                          • Field Statics 1
                          • Example Field Statics
                          • Residual Statics
                          • Without Statics
                          • With Statics
                          • Gradual Lateral Changes
                          • Long Wavelength Static Anomaly
                          • After Statics
                          • Post Stack Statics
                          • Severe Elevation
                          • Abrupt Lateral Changes
                          • Cross-Line Dip
                          • Seismic Velocities
                          • Errors in Stacking Velocity
                          • Judgement
                          • Picking
                          • Sampling Increment
                          • Window
                          • Random Noise
                          • Coherent Noise
                          • Range of Offset
                          • Near Surface Picking
                          • Errors in Stacking Velocity
                          • Flat Layer Non-Hyperbolic Moveout
                          • Bias
                          • Long Offset Data
                          • Errors in Stacking Velocity
                          • Semblance & Coherency Algorithms
                          • Uncertainty in T0
                          • Errors in Stacking Velocity
                          • Offset
                          • Speed
                          • Errors in Stacking Velocity
                          • Video: Viscosity of Fluids & Velocity Gradient - Fluid Mechanics, Physics Problems
                          • Module Quiz
                        • Module 9 - Interval Velocity Model

                          Contents:
                            • Dip Correction
                            • Bias Correction
                            • Method 1
                            • Method 2
                            • Method 3
                            • Method 4
                            • Interpolation
                            • Smoothing
                            • Interval RMS Velocity
                            • Sensitivity
                            • Rule
                            • Field Statics
                            • Editing
                            • Noise
                            • Filtering
                            • Smoothing
                            • Averaging
                            • Spatial Averaging
                            • Surface Fitting
                            • Smoothing
                            • Normalization
                            • Interval RMS Velocity
                            • Work Flow
                            • The First Macrovelocity Model
                            • Stacking Value Matching
                            • Travel Time Inversion - Tomography
                            • Summary
                            • Video: Seismic Tomography
                            • Module Quiz
                          • Post-Test

                            Kindly complete the post-test to assess your knowledge about the topic after the course.