AVO in an Inversion World
|Dr Anthony Fogg (Arun Geoscience, United Kingdom)|
|1 or 2 days|
|Geophysics – Seismic Reservoir Characterization|
|5 or 10 CPD points|
ACOUSTIC AMPLITUDE ANISOTROPY ATTENUATION IMPEDANCE ROCK PHYSICS RESERVOIR CHARACTERIZATION SEISMIC ATTRIBUTES
A short version of this course has been recorded as an E-Lecture. Watching this video will give you a clear introduction of what the course is about and it will help you to prepare yourself if you are going to attend it!
AVO (Amplitude Versus Offset) analysis has been a key technology for derisking drill targets as it can potentially distinguish different fluids and lithotypes. Over time the application of the AVO technique has evolved and merged with seismic inversion methods so that today the traditional AVO analysis techniques have been superseded by the analysis of rock property volumes on the interpreter's work station. However, in order to derive these rock properties we still rely on the fundamental principles of AVO. This course covers the basics of AVO theory and how it is used to create attributes or inversion volumes from seismic reflection data that reveal the rock and fluid characteristics of the sub-surface. The course is not mathematical, but does review some simple equations that help the student understand how AVO is applied to create quantitative measurements from surface seismic data and interpret those results in terms of rock physics - often referred to as Quantitative Interpretation (QI).
Upon completion of the course, participants will be able to understand the commercial application of AVO and have a basic understanding of seismic inversion methods and reservoir characterization, know what the results tell you in terms of rock physics and the possible limitations and errors in those results. Participants will be in a better position to critically analyse the results of such studies presented to them by contractors or partner companies. Participants will also be shown techniques to enable them to create some simple reconnaissance AVO data volumes using tools that are available in most interpretation packages.
- What is AVO and how does it occur;
- Measuring and classifying AVO responses;
- Incorporating AVO in to seismic inversion;
- Rock physics & elastic impedance;
- Generating rock physics data volumes from seismic inversion results;
- Seismic processing considerations – velocity, migration, bandwidth;
- Impact of anisotropy, VTI and HTI, and harnessing the effects;
- Case studies – conventional and unconventional (shale) resources.
Interpreters, geologists, geophysicists and other geoscience disciplines who have an interest in understanding how AVO, rock physics and seismic inversion is applied in real world studies.
Participants should have some knowledge of what seismic data is (pre-stack and post-stack) and what well log data is.
About the instructor
Anthony has provided integrated rock physics, AVO, inversion and interpretation studies to the oil and gas sector since the mid 1990's. He obtained his first degree in Geophysics (Geological) from the University of Leicester (UK) and his PhD in Geophysics from the University of Leeds (UK) where he was sponsored by British Coal. Anthony has an oil company background working as an explorationist in the UK North Sea for Amoco UK Exploration Ltd and as a QI consultant for Statoil ASA in Norway. He also spent a period working on and offshore undertaking wireline logging operations. For the last twenty years he has led geoscience teams in the provision of bespoke rock physics studies for private, national and multi-national corporations in basins across the globe. He has presented many technical papers and case studies at industry conferences and in journals and he has taught a variety of courses in the geosciences, including the industry renowned Hampson-Russell courses. He has given EAGE courses since 2012 and lectured to non-geoscience organisations, schools, universities and adult learning colleges promoting greater understanding of geology and geophysics by the general public. He also works as a Research Fellow at the University of Southampton in the Department of Ocean and Earth Sciences.
Explore other courses under this discipline:
Instructor: Dr Leo Eisner (Seismik)
The goal of this class is to explain principles of microseismic monitoring ranging from single monitoring borehole to surface and near surface networks. This class focuses on understanding the measurements made in passive seismic, their use and their uncertainties. Attendees should be able to decide on the best type of microseismic monitoring, design it, and know what kind of processing is needed to achieve their goals. They will also understand the uncertainties in the microseismicity. They will be able to avoid interpretation of uncertain observations. No requirement on prior class is needed, although knowledge of hydraulic fracturing and seismology helps. The course will also discuss the latest developments in microseismicity from source mechanisms, through tomography and anisotropy to reservoir simulations, including pore pressure analysis. The course discusses also social and scientific aspects of (induced) seismicity related to oil and gas reservoir.
Instructor: Dr Enru Liu (ExxonMobil)
The ability to identify fracture clusters and corridors and their prevalent directions within many carbonates and unconventional resources (shale gas, tight gas and tight oil reservoirs) can have a significant impact on field development planning as well as on the placement of individual wells. The characterization of natural fractures is difficult and cannot be achieved by any single discipline or single measurement. Geophysics can identify spatial distributions of fractures and fracture corridors between wells and seismically-derived fracture information to complement (not compete with) other measurements, such as outcrops, core, FMI, cross-dipole and other fracture information. This course is an introduction to the fundamental concepts of seismic fracture characterization by introducing seismic anisotropy, equivalent-medium representation theories of fractured rock and methodologies for extracting fracture parameters from seismic data. With a focus on practical applications, three case studies are presented to demonstrate the applicability, workflow and limitations of this technology: a physical laboratory 3D experiment where fracture distributions are known, a Middle East fractured carbonate reservoir and a fractured tight gas reservoir.
Instructor: Mr Olav Inge Barkved (Petoro)
Time-lapse seismic surveys or 4D seismic provide snapshots of a producing hydrocarbon reservoir and its surroundings. The benefit of the technology in monitoring fluid and pressure changes and to point out bypassed oil or un-drained compartments has been well documented over the last 10–15 years. Still the technology is undergoing rapid development. This course will provide some context on what is driving the dynamic changes linked to producing a hydrocarbon reservoir and what we should expect to observe using seismic technologies in a varied geological setting. It will address key issues that impact the feasibility of time-lapse seismic and evaluate established methods. However, the focus will be on ‘new’ technologies, use of a permanent array, frequent seismic surveying and integration of the data. Examples from the Valhall field will be used extensively to illustrate the potential of seismic data and to articulate issues related to interpretation and integration. This will include data examples from marine towed 4D, frequent surveying using permanently installed sensors, in-well recordings and analysis of passive data, including micro seismicity. Use of seismic surveillance information to support reservoir management, new well delivery and base management will be a central part of the presentation.
Instructor: Prof. Martin Landrø (Norwegian University of Science & Technology)
The course discusses various methods for monitoring subsurface injection of CO2. Specifically, the following topics will be covered:
- Rock physics related to injection of CO2 into porous rock
- Time-lapse seismic methods
- Gravity and electromagnetic methods
- Saturation and pressure effects
- Early detection of leakage
- Mapping overburden geology and identification of potential weakness zones
- Field examples
- Well integrity issues
- Using gas leakage as a proxy to study potential leakage of CO2
- Laboratory experiments of CO2 flooding including acoustic measurements
Instructor: Prof. Serge Shapiro (Freie Universitaet Berlin)
Stimulations of rocks by fluid injections (e.g., hydraulic fracturing) belong to a standard reservoir-development practice. Productions of shale oil, - shale gas, - heavy oil, - geothermal energy require broad applications of this technology. The fact that fluid injection causes seismicity (including microseismicity and, sometimes, significant induced earthquakes) has been well-established for several decades. Waste water injection into rocks, large-scale water reservoir constructions and underground carbon sequestrations are other examples of potentially seismogenic fluid impact on geologic structures. Understanding and monitoring of fluid-induced seismicity is necessary for hydraulic characterization of reservoirs, for assessments of reservoir stimulation results and for controlling seismic risk of fluid injections and production. The course provides systematic quantitative rock-physical and geomechanical fundamentals of all these aspects of the fluid-induced seismicity.
Instructor: Dr Dario Grana (University of Wyoming)
Integrated reservoir modeling workflows provide a set of techniques to create three-dimensional numerical earth models in terms of elastic, petrophysical and dynamic properties of the rocks at different time steps during exploration and production. The course focuses on the quantification of uncertainty in the data, in the physical models and in the predictions in reservoir modeling workflows. Topics include uncertainty quantification in seismic reservoir modeling, geostatistical reservoir simulations, fluid flow modeling, and reservoir monitoring. The link between uncertainty quantification and decision-making will be introduced through decision-making theory. The course will include demonstrations of the methodologies on real case applications.