Image Appraisal for 2D and 3D Electromagnetic Inversion [electronic resource].

Published: Washington, D.C. : United States. Dept. of Energy, 1999.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Physical Description: 48 pages : digital, PDF file
Additional Creators: Sandia National Laboratories, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information

Access Online

www.osti.gov

Availability

Finding items...

Restrictions on Access

Free-to-read Unrestricted online access

Summary

Linearized methods are presented for appraising image resolution and parameter accuracy in images generated with two and three dimensional non-linear electromagnetic inversion schemes. When direct matrix inversion is employed, the model resolution and posterior model covariance matrices can be directly calculated. A method to examine how the horizontal and vertical resolution varies spatially within the electromagnetic property image is developed by examining the columns of the model resolution matrix. Plotting the square root of the diagonal of the model covariance matrix yields an estimate of how errors in the inversion process such as data noise and incorrect a priori assumptions about the imaged model map into parameter error. This type of image is shown to be useful in analyzing spatial variations in the image sensitivity to the data. A method is analyzed for statistically estimating the model covariance matrix when the conjugate gradient method is employed rather than a direct inversion technique (for example in 3D inversion). A method for calculating individual columns of the model resolution matrix using the conjugate gradient method is also developed. Examples of the image analysis techniques are provided on 2D and 3D synthetic cross well EM data sets, as well as a field data set collected at the Lost Hills Oil Field in Central California.

Report Numbers

E 1.99:sand98-0995c
sand98-0995c

Subject(s)

Petroleum

Other Subject(s)

Note

Published through SciTech Connect.
01/28/1999.
"sand98-0995c"
1998 Society of Exploration Geophysicists Annual Meeting, New Orleans, LA (US), 09/01/1998.
Newman, G.A.; Alumbaugh, D.L.

Funding Information

AC04-94AL85000

View MARC record | catkey: 14703133