Gaussian scaling noise model of seismic reflection sequences: Evidence from well logs

Geophysics ◽  
1990 ◽  
Vol 55 (4) ◽  
pp. 480-484 ◽  
Author(s):  
J. P. Todoeschuck ◽  
O. G. Jensen ◽  
S. Labonte

A simple model for reflection series is desirable for two reasons: first, to have a means of generating model reflection sequences on which to test geophysical data processing techniques, specifically methods of predictive deconvolution, and second, to suggest a way of parameterizing real reflection sequences for classification and further geologic study. In this note we wish to discuss a model suggested by Hosken (1980); our discussion is founded upon the powerful ideas of self‐similarity and scaling developed by Mandelbrot (1983) and on the paucity of typical lengths in geology. Typical lengths are common in physics problems; for example, the length of an organ pipe governs the wavelengths of the notes played. When taking photographs, geologists include some manmade object to give scale to the photo. Otherwise it is very hard to tell if, say, folds are of centimeter size or form whole mountains.

2021 ◽  
Author(s):  
Clark R. Wilson

A concise introduction to geophysical data processing - many of the techniques associated with the general field of time series analysis - for advanced students, researchers, and professionals. The textbook begins with calculus before transitioning to discrete time series via the sampling theorem, aliasing, use of complex sinusoids, development of the discrete Fourier transform from the Fourier series, and an overview of linear digital filter types and descriptions. Aimed at senior undergraduate and graduate students in geophysics, environmental science, and engineering with no previous background in linear algebra, probability, or statistics, this textbook draws scenarios and datasets from across the world of geophysics, and shows how data processing techniques can be applied to real-world problems using detailed examples, illustrations, and exercises (using MATLAB or similar computing environment). Online supplementary resources include datasets for students, and a solutions manual and all the figures from the book as PowerPoints for course instructors.


Geosciences ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 283
Author(s):  
Allan Audsley ◽  
Tom Bradwell ◽  
John Howe ◽  
John Baxter

Sub-seabed gas is commonly associated with seabed depressions known as pockmarks—the main venting sites for hydrocarbon gases to enter the water column. Sub-seabed gas accumulations are characterized by acoustically turbid or opaque zones in seismic reflection profiles, taking the form of gas blankets, curtains or plumes. How the migration of sub-seabed gas relates to the origin and distribution of pockmarks in nearshore and fjordic settings is not well understood. Using marine geophysical data from Loch Linnhe, a Scottish fjord, we show that shallow sub-seabed gas occurs predominantly within glaciomarine facies either as widespread blankets in basins or as isolated pockets. We use geospatial ‘hot-spot’ analysis conducted in ArcGIS to identify clusters of pockmarks and acoustic (sub-seabed) profile interpretation to identify the depth to gas front across the fjord. By combining these analyses, we find that the gas below most pockmarks in Loch Linnhe is between 1.4 m and 20 m deep. We anticipate that this work will help to understand the fate and mobility of sedimentary carbon in fjordic (marine) settings and advise offshore industry on the potential hazards posed by pockmarked seafloor regions even in nearshore settings.


2006 ◽  
Vol 46 (9) ◽  
pp. S693-S707 ◽  
Author(s):  
P Varela ◽  
M.E Manso ◽  
A Silva ◽  
the CFN Team ◽  
the ASDEX Upgrade Team

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