Practical Introduction to Geophysics and Seismic Interpretation
This class provides an overview of seismic wave propagation, discusses important issues related to seismic data acquisition and imaging, and introduces students to practical seismic interpretation workflows including mapping techniques.
Description
This class provides an overview of seismic wave propagation, discusses important issues related to seismic data acquisition and imaging, and introduces students to practical seismic interpretation workflows including mapping techniques. Additional topics such as seismic attributes, borehole geophysics, reservoir characterization and reservoir surveillance are also included. Technical discussions will cover both conventional and unconventional reservoir topics along with some discussion of the relevance of geophysical methods to new energy systems.
The balance of topics covered and content can be discussed and refined with the client if required.
Tutor(s)
John Randolph: Consultant Geophysicist
Objectives
You will learn to:
- Explain the fundamentals of seismic wave propagation and factors affecting resolution at the reservoir level.
- Calibrate seismic data using well data.
- Communicate effectively with data acquisition and processing specialists.
- Execute an effective interpretation workflow for a 2-D seismic project.
- Apply interpretation fundamentals to design a 3-D workflow on a workstation.
- Utilize multiple offset volumes to perform reconnaissance AVO analysis.
- Apply basic seismic sequence stratigraphic interpretation principles.
- Perform time-to-depth conversions using simplified velocity models.
- Utilize common seismic attributes to characterize reservoirs.
- Generate volumetric estimates of recoverable reserves (EUR).
Level and Audience
Fundamental. Intended for early career geoscientists and for technical support staff who work with seismic data.
Duration and Logistics
Classroom version: 6 days; a mix of lectures (65%) and hands-on exercises (35%). The course will be scheduled over two consecutive weeks to suit the client. The manual will be provided in digital format and participants will be required to bring a laptop or tablet computer to follow the lectures. Exercises are built around a publicly available dataset and comprise a ‘red thread’ that runs through the class.
Course Content
Workflow training begins with the calibration of seismic data, the establishment of correlation loops and structural contouring. More advanced workflows, including depth conversion and the practical application of AVO using multiple offset volumes in the interpretation process, will be demonstrated. Direct hydrocarbon indicators and basic principles of seismic sequence stratigraphy will also be discussed during the lectures and exercise sessions.
Daily Agenda
Day 1
Introduction
- What is seismic data? What can it do? What are its limitations?
- Introduction to seismic wave propagation and elastic behavior of rocks
- How is seismic data recorded?
- What is required to generate useful subsurface images?
- What can go wrong?
- The interpreter’s role in working with acquisition and processing specialists
- Reservoir responses to seismic waves
- Seismic resolution
- Seismic reflectivity (Exercise 1.1)
- Synthetic seismograms
- Interpretation workflow (Exercises 2.1, 2.2, 2.3)
- Understanding the basin
- Calibration
- Tying correlation loops
Day 2
- Seismic acquisition
- Data processing (Exercises 1.2, 1.3)
- Seismic imaging (migration)
- Project management & data loading
- Reflectivity changes with angle – AVO
- Elastic reflectivity response
- Seismic amplitude case histories (Exercise 1.4)
Day 3
- Structural Interpretation workflow (Exercises 2.4, 2.5, 2.6)
- Mapping lineaments
- Using time slices
- Mapping the interpretation
- Seismic inversion methods
- Introduction to Quantitative Interpretation
- Quiz – Waves, reflectivity, inversion, acquisition, processing
Day 4
- Review day 3 quiz topics
- Review interpretation exercises 2.1– 2.4
- Team presentations of mapping exercises 2.5 & 2.6
- Using flattened seismic images (workflow)
- Introduction to seismic sequence stratigraphy
- Stratigraphic interpretation (exercise)
- Pore pressure estimation
Day 5
- Seismic velocity measurements
- Vertical seismic Profiles (VSPs)
- Velocity interpretation, exercise 2.7
- Workflow options for time/depth conversion
- Interpretation workflows on a workstation
- Seismic attribute applications (including AVO)
- Estimation of recoverable reserves in a reservoir (EUR)
Day 6
- Fractured reservoirs
- Distributed acoustic sensing (DAS) 4D
- Reservoir surveillance
- Cross borehole tomography in horizontal wells
- Characterization of shale reservoirs
- Case history discussions
- CO2 injection monitoring
- Geothermal reservoirs
Wrap-up discussion
List of exercises
- Seismic Well Tie Exercise: Using synthetic seismograms or VSPs.
- Interpretation Exercise: Constructing an interpretation baseline for a project.
- Interpretation Exercise: Tying interpretation loops for multiple horizons.
- Interpretation Exercise: Constructing a lineament map to guide the interpretation.
- Interpretation Exercise: Generating a structure map.
- Interpretation Exercise: Construction and use of isochron maps.
- Interpretation Exercise: Using 3-D time slices to validate an interpretation.
- Interpretation Exercise: Using time slices to validate an interpretation.
- Interpretation Exercise: Use of direct H/C indicators to estimate reservoir size.