News Archive

From time to time it is argued that cable-free systems would bring freedom in the choice of receiver station locations. To learn how this is viewed in the light of 3D symmetric sampling requirements, read the note "Noise suppression, prestack imaging and freedom of choice".

NMO stretch has an effect on the resolution of final stacked and migrated data that depends on the mix of offsets contributing to the final product. For the same range of absolute offsets, 2D data are less affected by resolution loss than 3D data. This is discussed in the note "NMO stretch for P- and C-waves and its link to resolution, AVO and mute offset".
The note also discusses the link between AVO-requirements and NMO stretch, the link between mute offset as a function of depth and NMO stretch, and the note describes NMO stretch for C-waves.

Wide-azimuth towed streamer (WATS) acquisition is a new technique with potential for better subsalt imaging. It is a highly expensive technique, because it involves traversing the survey area multiple times with varying crossline offsets between streamer vessel and source vessels. The expense of the technique has led to undesirable corner cutting such as acquiring data in only two of the four source-receiver azimuth quadrants. In some papers this cost-saving method has been justified on basis of reciprocity: reciprocity would make data acquired in opposite quadrants redundant.
The paper "Reciprocal offset-vector tiles in various acquisition geometries" presented at the 2007 SEG Conference held in San Antonio, Texas, argues that in sparse geometries data acquired in opposite quadrants are complementary rather than redundant.
The Power Point file of the paper as presented at the Conference can be viewed here as well (including presentation text in Notes pages).

The paper Processing orthogonal geometry - what is missing? tries to generate interest in geometry-oriented processing techniques specifically for orthogonal geometry (150 kb). It was presented at the 75th SEG Conference in Houston. The presentation slide show may also be viewed.

In the discussion on single sensors versus arrays arrays tend to get more beatings than they deserve. A discussion defending short arrays can now be read on this website.

The October 2004 issue of The Leading Edge featured a large number of interesting papers on Seismic Survey Design. Some comments on two of these papers have now been included (1.3 Mb).

The number of channels needed in an ideal acquisition geometry has been the subject of some debate, especially in connection with the advent of single-point acquisition (Q-technology), MEMS-type sensors, and the Infinite Telemetry system of Vibtech. The paper An ambitious land geometry contributes to the debate. It was published in the October 2004 issue of The Leading Edge and may also be downloaded from this website (128 kb).

The Recorder, the journal of the Canadian SEG, features a new series called “Expert Answers”. The April 2004 issue includes expert answers by Gijs Vermeer and Mike Galbraith on 3D seismic survey design. In the May 2004 issue Tessman and Cooper discuss digital geophones and in the June 2004 issue various experts discuss marine data acquisition. The April 2004 issue of the Recorder also features “A comparison of two different approaches to 3D seismic survey design” by Gijs J.O. Vermeer. All papers can be downloaded from the CSEG website.

The book “3-D seismic survey design” contains a CD-Rom with some design software, including a spreadsheet for survey design optimization. It also contains a 4-page paper to explain the technique. A more elaborate paper has now been published in the October 2003 issue of The Leading Edge. This paper 3D seismic survey design optimization may also be downloaded from this website (218 kb).

In the November/December issue of Geophysics the paper “Analyzing the effectiveness of receiver arrays for multicomponent seismic exploration” by Hoffe et al. was published. See for a short discussion Comments to Hoffe et al. See for the reply by Hoffe et al. the September/October 2003 issue of Geophysics.

The note Conventional wisdom was published earlier on this website. This note has now been expanded into an abstract for presentation at the 2003 SEG Conference in Dallas. The paper A comparison of two different approaches to 3D seismic survey design can be downloaded (300 kb).

In the November/December issue of Geophysics a paper by Gibson and Tzimeas was published. It compares the resolution of a complex medium for different acquisition geometries. See for a discussion Comments to Gibson and Tzimeas paper. Their interesting reply has been published in Geophysics, 2004, 619-623. The reply now contains resolution comparisons for data with about the same range of midpoints.

There are minor shortcomings in some figures in “3-D seismic survey design”. Download a pdf with corrected figures (1Mb)

Summary of PhD thesis with some figures (pdf, 875 kb).