Oil and Gas
Oil and Gas | Geophysics and Seismic Interpretation
The Interpreter’s Guide to Depth Imaging
Format and Duration:
2 days
4 sessions
The course begins with understanding the nature of velocities and reviews time-to-depth conversion as a prelude to understanding the limits of time migration. Next, is an intuitive overview of migration theory, Kirchhoff (ray) versus RTM (wave) algorithms, tomographic velocity updates, and advances in full-waveform inversion for the near-surface velocity model and deep velocity updating. It introduces intuitive quality controls and quantitative spreadsheet analysis to plan and ensure stable depth solutions during the iterative depth-imaging process. Advanced database-validation methods, such as cross plots between horizon interpretations and well tops, are used to identify and remove inconsistencies before deriving anisotropic parameters. A related database topic is defining the polarity and phase of the seismic and investigating the importance and precision of synthetic seismogram ties using P Impedance volumes and logs. The course continues with a robust approach to well-top calibration of the final depth deliverables. Additionally, freeware is provided to provide a statistical method for estimating depth uncertainty. Finally, the course reviews advanced attributes derived from depth imaging, including azimuthal inversion to yield lithologic and stress-field (fracture) properties, plus practical aspects of implementing machine learning for classification and estimation.
Business Impact: This comprehensive course equips participants with an interpreter-oriented approach to effectively utilize depth imaging in various geologic settings. Attendees will develop a solid understanding of the theory, practical application, and interpretive aspects of depth imaging, enabling them to expertly design, guide, and quality control depth-imaging projects.
Schedule
Duration and Training Method
This is an instructor-led course of 2 days or 4 on-line sessions. Training is conducted with a combination of lectures, demonstrations, and illustrative datasets.
Course Overview
Learning Outcomes
Participants will learn to:
- Appreciate time-to-depth conversion methodologies.
- Differentiate between time and depth migration.
- Distinguish between commonly used migration algorithms.
- Appraise methods for velocity updating (tomography/FWI) appropriate for the geology.
- Define target velocity resolution for tomography and related imaging grids.
- Establish consistency between well tops and horizons in an interpretive database.
- Plan and review QCs for iterative velocity updates.
- Assess the methods used for determining anisotropic parameters.
- Perform well-top calibration of depth-imaging volumes.
- Evaluate the validity/uncertainty of advanced seismic attributes.
- Review practical aspects of machine-learning classification and estimation.
Course Content
- Review of Vertical Time-to-Depth Methods
- Basic Concepts
- Velocity field representation
- Single-layer depth conversion
- Uncertainty analysis and pitfalls
- Time and Depth Migration: Comparisons
- Concepts in time and depth migration theory
- Contrasts between time and depth imaging
- Migration Algorithms: Theory and Practice
- Kirchhoff, Gaussian Beam, 1-way and 2-way (Reverse Time) Wave Equation
- Offset and angle domains for Common Image Point (CIP) Gathers
- Anisotropy and Multi-component considerations
- Migration: Parameter Selection
- Kirchhoff travel times and Wave Equation imaging conditions
- Amplitudes, aliasing, and aperture
- Regularization (interpolation) and equalization (migration weighting)
- Tomographic Velocity Analysis and FWI
- Layer- and grid-based ray methods
- Full waveform inversion (FWI) and FWI imaging
- Depth Imaging Grids
- Depth/Velocity: Visualization (imaging) and velocity representation
- Travel times/Propagation: Summation curves and/or wavefield extrapolation
- CIP picking/Tomography: Data input to tomography and velocity-update equations
- Well/Seismic Database Validation
- Determine data polarity and phase
- Creating synthetic seismogram ties: “Wiggle” and P Impedance
- QCs to detect/resolve database discrepancies
- Iterative Depth Imaging: Quality Control
- Creation and QC of the initial velocity model
- Forming the near-surface model: Full-wave form inversion and refraction solutions
- Iterative tomographic updates and target-velocity resolution
- Case histories
- Setting up an intuitive review of the iterative velocity-update process
- Anisotropy
- Anisotropic parameterization (Vz, Delta, Epsilon, VTI/TTI…)
- Initial Vz model, velocity and parameter updates
- Well Calibration
- Working in the time domain and updating the time/velocity (Vz) model
- Conversion of time data to calibrated depth
- Uncertainty measures (Stochastic modeling, freeware supplied and demonstrated)
- Depth-Imaging Attributes
- Poststack: Amplitudes, curvature, coherence
- Prestack: Elastic inversion and forming geomechanical volumes (Young’s, Poisson’s,)
- AVO with Azimuth and other HTI property cubes
- Practical applications of machine-learning algorithms
Who Should Attend and Prerequisites
Seismic interpreters incorporating depth imaging into their evaluations, and depth-processing imagers looking to better interact with interpreters. .
Instructors
Scott MacKay
Background
Scott MacKay is a petroleum geoscientist specializing in geophysics and geology, with extensive oil and gas exploration and exploitation experience. He started with a major oil company as an Exploration Geophysicist in Denver, developing structural and stratigraphic plays in the Williston and other Rocky Mountain Basins. He then joined the oil company’s Special Projects group in Houston as an Exploration Advisor, integrating the efforts of multidisciplinary teams in areas including the North Slope, Offshore Africa, North Sea, Colombia, and the Gulf of Mexico. After ten years, he joined what is now Schlumberger-WesternGeco as a Research Geophysicist developing advanced methods for depth migration. He was soon appointed Manager of R&D for WesternGeco where he also served as World-wide Coordinator for Depth Imaging, Time-lapse (4D) Reservoir Characterization, and Multicomponent Imaging. He was made a Schlumberger Advisor in 2003 and has five U.S. patents and many publications on applying innovative and practical solutions to seismic imaging issues.
Scott became an independent consultant in 2003, working domestic and international interpretation projects. He is experienced with Kingdom and Petrel for detailed evaluations and prospect generation. He also advises/mentors/trains O&G companies in applying appropriate seismic imaging technologies and interpretation techniques for play evaluation and risk reduction. He also specializes in managing anisotropic depth migration projects that span complex structure to subtle resource plays to quantify reservoir quality using advanced attributes including AVOAz (HTI) inversion. Recently, he has created advanced machine-learning estimations of Oil and Gas EURs from seismic and reservoir-model properties as part of several multidisciplinary development teams.
Affiliations and Accreditation
Ph.D. Geology and Geophysics; University of Houston; Houston, TX
M.Sc. Geophysics; Colorado School of Mines; Golden, CO
B.Sc. Geology and Chemistry(double major); Bridgewater State University; Bridgewater, MA
Courses Taught
N658: Practical Depth Conversion and Depth Imaging for the Interpreter
N659: The Interpreter's Guide to Depth Imaging
Accreditation and Certification
CEU: 1.4 Continuing Education Units
PDH: 14 Professional Development Hours
Certificate: Certificate Issued Upon Completion
RPS is accredited by the International Association for Continuing Education and Training (IACET) and is authorized to issue the IACET CEU. We comply with the ANSI/IACET Standard, which is recognised internationally as a standard of excellence in instructional practices.
We issue a Certificate of Attendance which verifies the number of training hours attended. Our courses are generally accepted by most professional licensing boards/associations towards continuing education credits. Please check with your licensing board to determine if the courses and certificate of attendance meet their specific criteria.