Articles
AVO analysis in the presence of NMO stretch and offset dependent tuning
Jonathan Downton
The effects of NMO stretch and offset dependent tuning on the estimates of AVO inversion and analysis may be quantified by an analytic expression. This expression shows that these effects primarily distort the AVO gradient while essentially leaving the intercept unbiased. The influence of these distortions is largely controlled by…
Seismic Exploration off Canada’s East Coast
Doug Bogstie and Andy Dyke
In December of 1901 Guglielmo Marconi transmitted the first transatlantic signal from Cornwall, England to St. John’s Newfoundland. The signal was received at a site that has come to be known as Signal Hill, from where you can overlook both the North Atlantic and North America’s oldest city, St. John’s…
Understanding a Doodlebugger
Brian Schulte
When I started to study Geology at the University of Calgary I never realized that my career would take me to some of the more interesting points in the world. I remember sitting in my Sedimentary class wondering why I was studying the Mississippi Delta or why we were learning…
Optimal marine streamer acquisition with High-Density 3D
Andrew Long, Bill Pramik and Marie Dunn
Our goal with the reflection seismic experiment is to obtain the most clearly defined, high-resolution image of the subsurface geology, free of contaminating noise. This goal can be achieved by acquiring seismic surveys with dense and even sampling in both time and space. Historically though, 3D marine streamer acquisition has…
AVO Modeling in Seismic Processing and Interpretation II. Methodologies
Yongyi Li, Jonathan Downton, and Yong Xu
Zoeppritz’s equations with ray tracing and full elastic wave equation with finite difference method (FDM) are two most commonly used techniques in AVO modeling. The main difference between these two techniques is the former calculates the primary-only reflectivities and the latter calculates particle displacements in subsurface. Zoeppritz modeling has the…
Gabor Deconvolution: extending Wiener’s method to nonstationarity
Gary Margrave, Linping Dong, Peter Gibson, Jeff Grossman, Dave Henley, and Michael Lamoureux
Seismic data is arguably always nonstationary in its Fourier spectral character since anelastic attenuation processes are present everywhere. The major mathematical tool for dealing with this effect in seismic data processing is the Wiener deconvolution algorithm, which is at least a half century old. Paradoxically, this algorithm assumes that the…
The bleeding edge of seismic imaging, 2003
Samuel H. Gray
Earlier this year, James Sun and I gave a CSEG Luncheon presentation describing the current state of the art of seismic depth migration, as it applies to Canadian basins. Our overview was aimed at bridging the gap between depth migration and velocity analysis methods routinely applied today, and newer methods…
2004 Election of Officers Candidates
Overview of 2004 CSEG election candidates.
... Some Issues related to Seismic Imaging in Deep-Water Basins
Mike Hall
Obtaining high fidelity seismic images in deep water basins has several challenges. These run from the issues of dealing with noise to building accurate interval velocity models for Pre-Stack Depth Migration (PreSDM). Exploration, and development, in such basins is commonly associated with deep targets that may well be associated with…
AVO Modeling in Seismic Processing and Interpretation Part 1. Fundamentals
Yongyi Li, Jonathan Downton, and Yong Xu
AVO analysis is an effective technique in reservoir characterization and its success relies on not only the quality of recorded seismic data but also data processing and understanding of rock physical properties. Since AVO modeling is able to link rock properties to offset-dependent amplitude responses, it is a tool in…
Propagation of borehole derived properties via a Support Vector Machine (SVM)
Yexin Liu and Mauricio D. Sacchi
Rock mechanical properties are an essential piece of information for applications like borehole instabilities analysis during drilling. It is estimated that borehole instability problems cost the oil industry worldwide about 1.0 billion dollars per year (Erling, et al., 1996). Traditional methods of propagating mechanical properties from a given borehole to…
Successful AVO and Cross-plotting
Satinder Chopra, Vladimir Alexeev, Yong Xu
Cross-plotting has evolved to be a widely used technique in AVO analysis, as it enables the simultaneous and meaningful evaluation of two attributes with ease. Generally, common lithology units and fluid types cluster together in AVO cross plot space, allowing identification of both the background lithology trends and anomalous off-trend…
Coal-Bearing Formations and Coalbed-Methane Potential in the Alberta Plains and Foothills
Andrew Beaton
Alberta contains substantial coal resources in the Plains and Foothills. Coal rank ranges from lignite and subbituminous in the eastern Plains, up to low-volatile bituminous and anthracite in the Foothills/Mountains. Potential coalbed methane targets exist in the Scollard Fm. (Ardley coal zone), Horseshoe Canyon Fm. (Carbon-Thompson, Drumheller coal zones), Belly…
A Summary of Coalbed Methane Potential in British Columbia
Barry Ryan
For the first part of 2003 wholesale natural gas prices have been in the range of 4 to 6 $US per million btu, this compares to prices of about 2.2 $US in 1998. The price increase reflects increased demand and a decrease in reserves within USA and Canada. In fact,…
Microbial Methanogenesis and its Role in Enhancing Coalbed Methane Recovery
Karen Budwill
It has been recognized in recent years that ongoing methane production is occurring in deep coal beds. This observation was deduced from studies of isotopic fractionation of coal gases, changes in coal-gas chemistry and the biodegraded nalkane pattern of some coal-extract samples (Scott, 1999). Research is limited in understanding the…
Michelangelo, Seismic and Seeing What’s There
Jan Dewar, Jon Downton, Glen Larsen
In oil painting restoration, masterpieces dirtied by centuries of grime and smoke are cleaned to reveal the original brilliant image. The recent cleaning and restoration of the frescoes in the Sistine Chapel are a familiar example. Once the unwanted dirt had been removed, the beauty and vibrant colors of the…
Visualization and Volume Interpretation in Geoscience: 3-D Seismic and Beyond
Steven R. May
Volume interpretation technologies are revolutionizing the way geoscientists interpret seismic data and engineers evaluate reservoirs, thereby improving the accuracy of subsurface predictions. The development and application of visualization and volume interpretation technologies within petroleum geoscience has experienced rapid change within the past decade. This history provides an interesting case study…
Multicomponent Seismic Data Acquisition… The Economics Revisited
John Gibson, Howard Watt, and Steve Roche
Over the past several years, significant advances have been made in the acquisition, processing and analysis/interpretation of converted-wave (PS) multicomponent seismic data resulting in renewed enthusiasm for use of this technology. The development of purpose-built multicomponent data acquisition systems based on MEMS (Micro Electro Mechanical System) digital accelerometers has resulted…
Full-Wave Digital Seismic Recording and the Impact of Vector Fidelity on Improved P-wave Data
D.J. Tessman and P. Maxwell
In 2002 Input/Output commercialized its full-wave digital sensor system known as VectorSeis™. Since the initiation of field testing in 1999 more than 65 surveys have been acquired worldwide with these MEMS (micro electro-mechanical systems) based sensors. Of these, 38 have been commercial seismic surveys in Western Canada. Observations by interpretation…
Combined Ocean Bottom Stations and Streamers
S. Ronen, C. Ansorger, R. Leggott, K. Hawkins, K. Mills, P.Nicholls, A. Ratcliffe and L. Scott
We propose to combine sparse multi-component (MC) seismic data with dense single component (1C) data. Such a combination provides the best of both: cost effective imaging and AVO analysis from the streamers, together with cost effective VP/VS ratio and MC AVO from the multi-component ocean bottom stations.
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