Sunday, December 28, 2014

Elements 3rd edition

Work is progressing well on the 3rd edition of Elements of 3D Seismology. I have hand-edited the hardcopy book through Chapter 21, revised MS Word documents through Chapter 20, and developed several new figures for the interpretation section. Here are a couple of the new figures.

Figure 1. Integrated seismic/well depth map for top of Mississippian Limestone formation in SE Kansas. (a) Horizon time structure map t(x,y) from 3D seismic data (2 ms contours). (b) Contoured average velocity map v(x,y) from seismic datum to top Miss using 4 wells (10 ft/s contours). (c) Depth map created by grid math z(x,y) = v(x,y)•t(x,y)/2 then corrected for seismic data to subsea depth (10 ft contours).

Figure 2. Geobody extraction for gas bright spot in the North Sea. (a) Vertical seismic line from 3D survey showing bright spot amplitudes. (b) Connected area amplitude threshold geobody grown from a single seed. (c) Map view of geobody colored blue and seed point in red. (d) Map view of geobody colored by z values with shallow points red and deeper portions yellow to gray.

Back to work....

7 September 2014

As some of you know, I am revising my book Elements of 3D Seismology for a 3rd edition to be published by SEG.  My method, after much consideration, has been to mark up the printed 2nd edition version by hand, then I will edit the doc files and push them off to SEG for later work.

The 2nd edition has 557 pages, not counting the bibliography.  Right now I am on p333.  I think it was Samuel Johnson who said "A man can turn over a small library to make one good book", and I know what he means.  Here is a photo of p73 with my hand edits. Going through my ~80 book geophysical library I find much confusion about Fresnel zone, mainly uncertainty about whether the author is talking about diameter or radius of the zone.  Wiggle words like 'width', 'size', and 'dimension', don't help. I'm sticking with 'radius' in the 3rd edition...

Elements of 3D Seismology 3rd edition (revision in progress, p73 of 557).

Here is the 'yellow pad' version of part of p73 that will be in the 3rd edition.

Thursday, December 18, 2014

New Donations: SWN and CGG

This was a great month for UA Geosciences.  We received a 3D seismic project donation from SWN (thanks to Damien Friend for championing), and HR-10 seismic analysis software from CGG (thanks to Brian Russell).

SWN Desoto 3D data includes 9 sq. mi. of seismic data and inversion attributes such as acoustic impedance (AI).  Cool colors are low AI and hot colors are high values. The green Low-AI interval is the Mississippian Fayetteville Shale, a prolific gas producer.  Within the Fay Shale interval an anomalously low AI interval is evident, likely a zone more rich in organic matter. 
AI data allows more intuitive correlation between seismic and stratigraphic column for surface exposures in the Ozark plateau of N Arkansas. 
There is a natural connection between the SWN data donation and the HR-10 software donation, namely acoustic impedance.  A key strength of HR-10 is ability to do AI inversion of seismic plus well data.  This is a good space for UA geology graduate students to work, inversion is an important skill, much in demand in the petroleum industry. Here is a figure from HR-10 documentation.

AI and seismic data from HR-10 post-stack inversion tutorial.