Articles
Filling in the Gaps in Our Understanding of Converted-Wave Fold
Peter Cary and Don Lawton
For a newcomer to converted-wave processing, one of the most confounding things that is encountered early on is the realization that the fold of P-S data can differ so much from the fold of ordinary P-P data.
... Analyzing Multicomponent Seismic Data from the Mackenzie Delta, N.W.T.
Carlos E. Nieto and Robert R. Stewart
A set of seismic test lines was acquired in the spring of 2001 by the CREWES Project and Devon Canada Ltd. (formerly Anderson Exploration Ltd.) in the Mackenzie Delta, N.W.T. The lines, shot with dynamite and vibrator sources, included a 750m spread of 3-C geophones across a transition zone from…
9C, 4D Seismic Processing for the Weyburn CO2 Flood, Saskatchewan, Canada
Robert R. Kendall, Robert Winarsky, Thomas L. Davis and Robert D. Benson
We present a summary of the 9C, 4D processing used for the seismic monitoring of a CO2 flood in the Weyburn Field, Saskatchewan, Canada. The resultant time-lapse amplitude anomalies for both the P- and S-wave volumes are coincident with the locations of the CO2 injection patterns. Furthermore, the anomalies we…
Utilization of Seismic Attributes for Reservoir Mapping: A Case Study from Cambay Basin, India
A.K. Srivastava, V. Singh, B.G. Samanta and G. Sen
Multi-layered Hazad sands of Middle Eocene age deposited in deltaic environment are the main hydrocarbon producers in south Cambay Basin, India. These sands are broadly divided into twelve units (1 to 12) from bottom to top. These individual sand units are further subdivided in to smaller subunits which are selectively…
The Controversial Pore Pressure Conversion Factor: PSI to PPG MWE
Selim S. Shaker
Geoscientists are inclined to use pore pressure (PP) plots expressed in PSI vs. Depth (P-D). This graphic illustration is beneficial for prospect and play-concept compartmentalization and seal integrity appraisals. On the other hand, drillers and engineers prefer to use Mud Weight Equivalents (MWE) in pound per gallon vs. depth (PPG-D)…
Russian Oil and Gas: A Compelling but Troubled Future
Michael J. Economides
An energy story, bigger than Iraq, bigger than Venezuela and Nigeria combined, is unfolding in Russia. The government of President Vladimir Putin has thrown down the gauntlet at oil “oligarchs”, most prominent among which is Mikhail Khodorkovsky, CEO of Yukos, Russia’s largest oil company and the world’s second largest oil…
Pseudo Gamma Ray Volumes Estimated from Offset Seismic
David Timko
Using seismic to explore for clastic reservoirs in the Western Canada Sedimentary Basin is often difficult due to the inability to distinguish between interbedded sand and shale lithologies using acoustic impedance. The problem is made even more difficult when the AVO response to sand-shale interfaces distorts the reflection amplitudes on…
Multi-Attribute Seismic Analysis on AVO derived parameters – a case study
Satinder Chopra and Doug Pruden
Prospecting for reservoir zones in mature trends sometimes requires unconventional exploration tools. AVO has been successfully used as a direct hydrocarbon indicator in some clastic rocks. Lately, AVO inversion for Lame parameters (λρ and μρ) has been shown to enhance identification of reservoir zones (Goodway et al, 1997). However, the…
Seismic anisotropy of shales
Pavlo Y. Cholach and Douglas R. Schmitt
Shales are volumetrically the most abundant sedimentary rocks. Shales are also known to be anisotropic to the propagation of seismic waves. Thick shale layers may significantly affect seismic wave propagation and contribute to the distortion of a seismic image. The elastic behavior of shales is usually associated with the properties…
Summary of the Poisson’s Ratio Debate 1990 – 2003
Peter Gretener
Summary of the Poisson's Ratio Debate 1990 - 2003
... The New Role of Petrophysics in Geophysical Interpretation
E.R. Crain
The role of petrophysics in seismic interpretation has taken a major leap forward in the past ten years, resulting from important advances in seismic data processing techniques, particularly seismic inversion, attribute analysis, and amplitude versus offset methods that showed we could estimate reservoir properties from such data. Coupled with the…
VSP Reflection Points for Linear Inhomogeneity and Elliptical Anisotropy
C.J. Wheaton and M.A. Slawinski
An exact analytical expression for traveltime in a medium with a constant velocity gradient and elliptical velocity dependence is used to calculate possible reflection points for a given source receiver geometry. The set of reflection points are collectively referred to as the illumination zone. Also, we give an expression that…
DoodleTrain on Track
Bill Nickerson
... Smearing the sideslip and other anisotropy problems, or — “Don’t hate me because I am beautiful: 3D anisotropic depth migration in the Canadian Foothills”
Robert Vestrum
Seismic waves exhibit fascinating, non-intuitive behaviours in the presence of anisotropy. Seismic anisotropy refers to the characteristic of materials, such as shale-dominated clastics, where the seismic velocity changes with direction of wave propagation. We explore wave-propagation phenomena and their effects on seismic imaging of complex-structure exploration targets below anisotropic strata.
... Where you sit governs what you see
Heloise Lynn
If you sit at a seashore, you see sand and waves and ocean and sky …..or, do you see sand and dune and cliff and rocks and trees and sky? Well, obviously, which way you face governs what you see (unless you have eyes in the back of your head).…
Permeability Anisotropy from Seismic Anisotropy and Other Holy Grails
Heloise Lynn
Permeability anisotropy from seismic anisotropy is an exciting avenue to gain insights into the aligned flow conduits – the aligned connected porosity – which set up a form of seismic anisotropy.The last SEG Annual Meeting (2002) had an entire session on the relationships between seismic anisotropy and permeability anisotropy. [Do…
High-dimensionality 3D seismic data visualization and interpretation: Simultaneous interpretation of nine co-rendered volumes
Heloise Lynn, Ping Chen, and Chenyi Hu
Many 3D volumes of attributes derived from travel times or amplitude measurements are useful for geologic insights when wide-azimuth, or multicomponent surveys are processed for the attribute value itself and the azimuthal characteristics of the value. For wide-azimuth 3D PP data, Vrms PP, Vint PP, AVO, and their elliptical variations…
Interpreting seismic data in the presence of azimuthal anisotropy; or azimuthal anisotropy in the presence of the seismic interpretation
Marty Williams and Edward Jenner
Measuring P-wave azimuthal anisotropy has been in the recent past an elusive task; therefore, the interpreter ignored this attribute of the seismic data and left the subject to the research and technology group geophysicists. Conversely, the interpreting geophysicist knew that when measured, the anisotropy could yield important reservoir properties related…
Fractured Reservoir Characterization using AVAZ on the Pinedale Anticline, Wyoming
David Gray, Sean Boerner, Dragana Todorovic-Marinic and Ye Zheng
The Pinedale Anticline in Wyoming, USA, has become an area of particular interest since the recent success of several wells that have produced significant volumes of gas from its tight sandstone reservoirs. Production from these reservoirs is now possible using new stimulation techniques developed in the neighboring Jonah Field. The…
Mars in Canada: The NASA Haughton-Mars Project, Devon Island, Nunavut
Robert R. Stewart
The Haughton meteorite impact structure on Devon Island, Nunavut is a fascinating geologic site as well as one of the most Mars-like places on Earth. Similar, but not quite as harsh as Mars, the Haughton crater is cold (average temperature –17°C), dry, rocky, dusty, and windy. Dr. Pascal Lee, of…
