N080 Geophysics for Subsurface Professionals

Course Facts

Course Code:
N080
Duration:
4 days
Type:
Classroom
CEU:
3.2 Continuing Education Units
PDH:
32 Professional Development Hours
Certificate:
Certificate Issued Upon Completion

Summary

This course will provide a practical understanding of what the seismic method can provide to evaluate geologic risk, characterize reservoirs and estimate resource potential. The course also provides an appreciation of the strengths and weaknesses of key seismic methods such as migration and inversion. Additionally you will know what questions to ask about structural imaging and depth maps, seismic prediction of reservoir properties such as lithology, porosity, fluid type, thickness and fractures as well as pressure prediction. You will also learn a practical workflow for interpreting 3D seismic.

Duration and Training Method

The course will run for 4 days and include classroom instruction, worked examples, exercises and discussion. 

Participants will learn to:

  1. Describe the fundamentals of seismic propagation using wavefronts or raypaths, as appropriate
  2. Identify the various types of seismic waves and their relevance to different scenarios
  3. Appreciate the importance of rock parameters, especially velocity and density, in understanding the results of the seismic method
  4. Describe the fundamentals of surface and borehole seismic acquisition and processing
  5. Appreciate the difference between the time and depth domains and how to convert between them
  6. Recognise the importance of resolution and how to maximise it
  7. Appreciate how seismic data is affected by rock properties such as porosity, lithology, fluid content, fractures and pressure
  8. Recognise how it is possible to estimate rock properties from the seismic data using AVO and inversion techniques
  9. Recognise the power of time-lapse and multi-component techniques in improving the discriminating power of the seismic data
  10. Apply a 3D seismic interpretation workflow to a large survey over the Gippsland Basin, offshore Australia. Hands-on interpretation of a regional seismic grid serves to reaffirm key interpretation concepts

Preface: comparison of seismic workflows for conventional and unconventional plays

Introduction

  • Basic concepts – types of sources, types of waves – surface, body, P, S
  • Wavefronts vs. raypaths
  • Velocity and density, acoustic impedance
  • Reflections, reflection coefficient, depth to time conversion
  • Shot gathers, single fold, multiple fold
  • Stacking and zero-offset concept
  • 2D geometry and coverage

 Structural imaging

  • Modelling – normal incidence, vertical incidence
  • Principles of 2D marine and land acquisition
  • 2D processing – statics, velocity analysis, NMO, stack
  • Time migration, migration velocity, diffractions
  • Simple depth conversion, average and interval velocity

Borehole geophysics

  • Sonic logging - conventional and dipole
  • Check Shots
  • VSPs - Vertical, Walkabove, Offset, Walkaway
  • Cross-well seismic

Calibrated reservoir mapping

  • Wavelets, frequency domain, phase
  • Calibration to wells
  • Vertical resolution, wedge model, tuning
  • Horizontal resolution, diffractions, aperture
  • Synthetic seismograms
  • Amplitude mapping for sand thickness
  • Porosity prediction and mapping

3D seismic imaging

  • 3D land and marine acquisition
  • 3D binning, processing and time migration
  • Image ray tracing, depth migration
  • Complex depth conversion and map migration

Lithology, porosity and fluid prediction

  • P and S waves, earth parameters, moduli, Poisson’s ratio
  • Fluid substitution
  • AVO modelling and analysis – reconnaissance and detailed
  • Inversion for acoustic and elastic impedance and Poisson’s ratio

 Fracture detection and anisotropy

  • Anisotropy – azimuthal, VTI
  • Fracture detection and mapping
  • Effect on velocities and AVO

Pressure prediction

  • Causes of overpressure, shale porosity, equivalent depth, Eaton method
  • Prediction from sonic log
  • Prediction from seismic velocities

Time lapse (4D) seismic

  • Basic concepts
  • Data acquisition and processing
  • Case studies

Multicomponent seismic

  • Data acquisition and processing
  • Case studies

3D Seismic interpretation workflow

  • Gippsland basin 3D, offshore Australia

Who should attend

This course is designed for geologists, engineers and petrophysicists involved in teams using geophysical techniques as well as individuals responsible for managing or supervising exploration or asset teams.

Prerequisites and linking courses

There are no prerequisite courses but participants should have a general understanding of the exploration process and be prepared for some technical discussion.

Recommended geophysical courses that build on N080 include N004 (Essentials of Rock Physics and Seismic Amplitude Interpretation) and N049 (Seismic Attributes for Exploration and Reservoir Characterisation). Participants interested in seismic interpretation should consider courses N085 (Introduction to Seismic Interpretation) and N040 (Interpretation of Three-Dimensional Seismic Data).

Click on a name to learn more about the instructor

John Chamberlain

John Randolph

Steve Western

Related Subjects

Excellent course, well taught by someone with real industry experience.