Articles
Microseismic Event Locations using the Double-Difference Algorithm
Fernando Castellanos and Mirko van der Baan
In this work we describe a reprocessing technique to relocate microseismic events based on the double-difference method. First, we use a crosscorrelation technique to assess waveform similarity between events and identify multiplet groups. Then, we correct relative arrival time inconsistencies between doublets. Next we apply the double-difference algorithm, which is…
Reservoir heterogeneity and ‘stealth’ zones in microseismic: Role of rock fabric
Per Kent Pedersen and David W. Eaton
For a single stage of a hydraulic-fracture treatment, microseismic monitoring surveys often reveal event clouds that contain intervening regions where microseisms appear to be sparse or absent (“stealth zones”). Scaling relations from earthquakes suggest that typical microseismic moment magnitudes, in the range of -3 < Mw < -1, occur on…
Broadband microseismic observations from a Montney hydraulic fracture treatment, northeastern B.C., Canada
David Eaton, Mirko van der Baan, Jean-Baptiste Tary, Brad Birkelo, Neil Spriggs, Sarah Cutten and Kimberly Pike
A research project was undertaken in August 2011 for continuous passive monitoring of a multistage hydraulic fracture stimulation of a Montney gas reservoir near Dawson Creek, B.C., with the main objective of investigating low-frequency characteristics of microseismic events. This work was motivated by a recently discovered class of long-period longduration…
Chief Geophysicists’ Forum Microseismic sub-committee – Microseismic Survey
Chris Szelewski and Heath Pelletier
The Microseismic (MS) sub-committee of the Chief Geophysicists’ Forum (CGF) was formed in June, 2011 in response to the growing industry interest in, and use of MS and the recognition that there was an urgent need for standardization in MS data collection, documentation and deliverables.
In order to better understand…
Guidelines for Standard Deliverables
Shawn Maxwell and Florence Reynolds
The following guidelines were created through the Microseismic sub-committee of the CSEG Chief Geophysicists Forum (CGF) and have been endorsed by both the CGF and CSEG. The intention is to define the components of a microseismic project, but purposely avoid the issue of data formats. Separate initiatives are currently attempting…
Simultaneous time-lapse processing for improved repeatability
Jeff Grossman
In conjunction with amplitude-friendly simultaneous processing of time-lapse seismic data, we introduce a QC scheme that steers the processing towards optimal time-lapse repeatability. We compute NRMS errors between stacked traces for different vintages of a survey after each main step of simultaneous processing. A processing step (which may include intermediate…
Introduction to this special section: Reservoir Characterization
Satinder Chopra
We have now reached the stage where reservoir characterization has come to be known as a discipline of its own. Some universities have started offering a master’s degree program on reservoir characterization so that the required knowledge and skill sets can be imparted directly to the students. We have already…
Dynamic reservoir characterization of the Lower Cretaceous Paluxy Formation, Delhi Field, Louisiana
Holly Robinson and Tom Davis
Delhi Field is a producing oil field located in the Madison, Franklin and Richland parishes of northeastern Louisiana (Figure 1). The field is 15 miles long and 2 to 2.5 miles wide, with an aerial extent of 6,200 acres. Delhi Field was discovered in 1944 and is estimated to contain…
Characterization of a heavy oil reservoir combining multiattribute analysis and spectral decomposition for density prediction, Maturín Sub-basin, Venezuela
Fabiola Ruiz and Milagrosa Aldana
The main objective of this work is to characterize a heavy oil reservoir located at the southern flank of the Maturín Sub- Basin. A rock physics analysis showed that the acoustic impedances of sandstones and shales are very similar within the reservoir, but density is a good lithological indicator. Hence,…
Seismic Lithology Prediction: A Montney Shale Gas Case Study
John Nieto, Bogdan Batlai, and Franck Delbecq
In any oil or natural gas development – conventional or unconventional – it is important to understand lithology, as it is a fundamental building block for all reservoir characterization work. Field development is enhanced by the ability to spatially predict different rock-types which in turn have different properties such as…
New attribute for determination of lithology and brittleness
Ritesh K. Sharma and Satinder Chopra
The discrimination of fluid content and lithology in a reservoir is an important characterization that has a bearing on reservoir development and its management. For the unconventional reservoirs, such as shale gas formations, besides other favorable considerations that are expected of them, it is vital that reservoir zones are brittle.…
Introduction to the Fracture Analysis Focus Articles
Bill Goodway
The paradigm change of hydraulic fracture stimulation is to artificially create reservoirs in unconventional source rocks, where production was previously unimaginable. Effective stimulation requires either the connection to existing natural fractures or the presence of geomechanical brittleness capable of supporting extensive induced fractures. As very few tight formations are thick,…
A Math-free Look at Azimuthal Surface Seismic Techniques
Franck Delbecq, Jon Downton and Mark Letizia
Many interpreters are interested in characterizing fractured reservoirs using 3D surface seismic data, and there are a variety of azimuthal techniques to extract this information from the data. However, once the results from two or more methods are compared the question may arise: why do the results from various azimuthal…
Microseismic, 3D and 4D Applications and its Relation to Geomechanics and Completion Performance
Andrew Iverson, Bill Goodway, Marco Perez and Greg Purdue
This study demonstrates empirical relationships derived from microseismic, 3D inversion attributes and 4D seismic to production in unconventional shale in the Horn River Basin. Production variations are explained through the use of the above mentioned tools and a careful investigation of stimulated rock volume. These production variations are shown to…
4D attenuation analysis for permeability estimates in hydraulically induced fractures
David Cho, Bill Goodway, Marco Perez, Andrew Iverson and Gary F. Margrave
The effect of wave induced fluid motion between fractures and pores results in complex elastic stiffness coefficients that ultimately gives rise to frequency-dependent attenuation. Therefore, permeability estimates are obtainable through a spectral analysis of the seismic wavefield. In this study, we analyze the attenuation response associated with a time-lapse seismic…
CSEG Foundation-sponsored Geophysicist returns to the Bottom of the World…
Susan R. Eaton
was snorkeling in a gin-and-tonic mix of brash ice near a gentoo penguin colony in Antarctica, in February 2010, when a leopard seal charged me, not once but three times, its mouth agape and jaws seemingly detached. Squaring off face-tomask— the leopard seal’s face, my scuba diving mask—I counted the…
An Introduction to Wavefield Visualization: Part 1 Visual Acoustics
Steven Lynch
When writing a paper, convention dictates that you begin with a summary, a concise outline of the subjects that you will cover in more detail in the body of the article. This paper is different because it is itself a summary being little more than an overview to an introduction.…
Introduction to the Processing – Migration / Imaging Focus Articles
Peter Cary
Imaging is always the ultimate aim of seismic processing, and this is usually accomplished primarily by one of the last steps in the processing sequence: migration. This month we have a very interesting and eclectic group of papers devoted to the topics of migration and imaging. Some of these papers…
Complex-beam Migration and Land Depth Imaging
Tianfei Zhu
Gaussian-beam depth migration is a useful alternative to Kirchhoff and wave-equation migrations in imaging geologically complex land areas. It overcomes the limitations of Kirchhoff migration in imaging multipathing arrivals and suffers no dip limits from one-way wave equation approximation. The accuracy of the Gaussian-beam method in solving the wave equation…
Deconvolution After Migration
John C. Bancroft, Thais Guirigay, and Helen Isaac
Deconvolution is a process that is normally applied before migration. However, deconvolution should also be performed after migration to enhance the resolution of the data. This concept has been practiced with some marine processing, but we have met considerable opposition when applying it to land data. We discuss some reasons…
