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45408-AC8
Reflectivity from Noise

Gerard Schuster, Unibversity of Utah

We have completed the first year of our research titled "Reflectivity from Noise".

There are four new developments sponsored in our ACS grant.

1). We have discovered a new way to utilize scattered energy to go beyond the

sqrt(N) law of signal-to-noise enhancement, where N is the number of geophones

that record seismic data. The new law we have discovered is that signal-to-noise

can be improved by sqrt(NM), where M=T/T_0.

Here T is the total recording time of a trace and T_0 is the dominant period of the source wavelet.

We have validated this law with both synthetic tests and field experiments. Two field

tests were conducted, a 60-channel seismic experiment in a Utah steam tunnel and a 120-channel

experiment in Arizona. The application for this new methodology is for a variety of uses, including

detecting trapped miners in lost mines and for detecting the location of hydro-frac sources. We are

writing a paper and will submit it to Nature or Science in the next month.

We have also validated the super-resolution properties of multiple scattering in a seismic field experiment, perhaps

the first time this has been done. I have included the results in my new book "Seismic Interferometry"

which will be published sometime in 2008. I have acknowledged the support of ACS in the book's preface:

" The American Chemical Society is acknowledged for their 2007-2009 grant ACS-45408-AC8 that resulted in the development of seismic source estimation with a natural Green's function. "

We will submit an expanded abstract to the 2008 SEG annual meeting committee.

2). We have developed a new method to image VSP and SSP data using the interferometry concept. We use

the VSP data to migrate below salt without needing to know the velocity model. This is a significant improvement

over the previous breakthrough of Calvert et al. (2004) who created virtual seismic sources from VSP data

but were restricted to imaging

data around the well. We have broken that restriction.

We will submit an expanded abstract to the 2008 SEG annual meeting committee.

3). We have developed a new method for imaging converted VSP data to image salt flanks.

We will submit this work as an abstract to the 2008 SEG annual meeting.

4). We recently were given 17 minutes of 3D passive seismic data from the company "Microseismic". Our results

are very encouraging as we are able to compute virtual direct waves and surface waves. There is

strong evidence that we have extracted reflections as well. We are submitting a new request to get

days of such data.

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