Course unit details:
Key Interpretation Skills
| Unit code | EART60381 |
|---|---|
| Credit rating | 15 |
| Unit level | FHEQ level 7 – master's degree or fourth year of an integrated master's degree |
| Teaching period(s) | Semester 1 |
| Offered by | Department of Earth and Environmental Sciences |
| Available as a free choice unit? | Yes |
Overview
This unit will be delivered using asynchronous, pre-recorded lectures in preparation for weekly synchronous activities. Synchronous activities will include practice exercises (log and seismic interpretation, calculations and interpretations), demonstrations, quizzes and Q&A.
The unit comprises two principle components:
Petrophysics and formation evaluation, which is the study of rock physical properties including texture, pore network and rock strength using 1D geophysical and geological data. This unit will introduce the fundamental principles of petrophysics and its importance to subsurface resource evaluation. It focuses in particular on core and geophysical wireline logs, which are the most common petrophysical toolkits for determination of lithology and calculation of porosity, fluid saturation, permeability and rock mechanical properties.
Seismic, acquisition and processing, which investigates how structure and stratigraphy are imaged in the subsurface using 2D and 3D geophysical data. The methodologies used to collect reflection seismic data and other geophysical datasets will be introduced and how that data is processed, evaluated and quality controlled evaluated. It will also introduce the interpretation of 2D and 3D seismic data.
This course unit detail provides the framework for delivery in 21/22 and may be subject to change due to any additional Covid-19 impact. Please see Blackboard / course unit related emails for any further updates
Aims
To develop an understanding of the key geophysical techniques (well log and seismic) used in the evaluation of the subsurface, including the principles of lithology determination, porosity calculation, permeability measurement and calculation of saturation.
Learning outcomes
On the successful completion of the course, students will be able to:
- Describe subsurface geophysical and geological data acquisition for characterisation and quantitative analysis of subsurface reservoirs, and their pros and cons
- Interpret lithology from geological logs, including Vshale analysis, and calculate net to gross from core and geophysical log data
- Measure porosity using routine core analysis and from the density, neutron and sonic logs and describe the differences between the values
- Be able to measure permeability at multiple scales using Darcy’s Law and estimate permeability using measured pore volume
- Calculate rock and fluid resistivity, determine fluid saturation using resistivity logs and select the most appropriate saturation model for the reservoir
- Assess uncertainty associated with the different methods used to determine porosity, permeability, Sw and net to gross and their impact on reservoir volumes
- Describe the principles of seismic acquisition, including the theory and common practice both onshore and offshore
- Demonstrate the techniques involved in seismic processing of 2D and 3D reflection seismic data
- Conduct basic seismic interpretation
- Identify and evaluate other advanced geophysical techniques, their uses and limitations
Syllabus
Week 1: Introduction to petrophysics and the borehole environment, exploring how data is collected during drilling and logging and the fundamentals of wireline log measurement
Week 2: Lithological interpretation of wireline logs, including how the gamma ray, combined neutron-density and resistivity logs can be used to interpret lithology, and the role of advanced tools such as borehole image logs
Week 3: Porosity determination from core and wireline logs, including how porosity is determined in core using helium intrusion and from thin sections, and the different methods for calculating porosity using the neutron, density and sonic logs
Week 4: Field classes (EART 60031)
Week 5: Permeability measurement and estimation, including permeability measurement through gas and fluid flow experiments and the use of porosity-permeability transforms and downhole methods for permeability calculation.
Week 6: Reading week
Week 7: Saturation determination from core and wireline logs, including the principles of capillary pressure measurement and how saturation is calculated downhole using resistivity tools
Week 8: Acquisition of, and standard processing involved in, land and marine 2D and 3D reflection seismic data.
Week 9: Advanced seismic techniques (pre-stack depth migration, synthetic seismograms, VSPs, AVO, etc).
This module will be delivered as 10 sessions with up to 2 hours asynchronous lecture material and pre-read material, prior to weekly 2 hour synchronous teaching, focused on problem solving and data analysis
Assessment methods
In-class petrophysical interpretation of core analysis and wireline log data (0%)
Final examination (seismic interpretation), 1.5 hours (50%)
Final examination (petrophysics), 1.5 hours (50%)
Feedback methods
In-class petrophysical interpretation of core analysis and wireline log data (0%)- Discussion of Solution in-class and posted on Blackboard.
Final examination (seismic interpretation), 1.5 hours (50%)- Marked online assessment.
Final examination (petrophysics), 1.5 hours (50%)- Marked assignment.
Recommended reading
Study hours
| Scheduled activity hours | |
|---|---|
| Lectures | 15 |
| Practical classes & workshops | 15 |
| Independent study hours | |
|---|---|
| Independent study | 120 |
Teaching staff
| Staff member | Role |
|---|---|
| Catherine Hollis | Unit coordinator |