Monitoring subsurface changes over time with cross-well electromagnetic tomography

Journal Article · Sun Oct 01 04:00:00 EDT 1995 · Geophysical Prospecting

DOI:https://doi.org/10.1111/j.1365-2478.1995.tb00286.x· OSTI ID:136693

Alumbaugh, D L ^[1]; Morrison, H F ^[2]

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1. Sandia National Labs., Albuquerque, NM (United States)
2. Univ. of California, Berkeley, CA (United States)

A fast imaging technique is developed to deduce the spatial conductivity distribution in the earth from low-frequency (<1 MHz) cross-well electromagnetic measurements. A sinusoidally oscillating, vertically orientated, magnetic dipole is employed as a source, and it is assumed that the scattering bodies are azimuthally symmetric about the source dipole axis. The applicability of cross-well electromagnetics for imaging and monitoring changes caused by subsurface processes has been tested by simulating plumes of conductive fluid with 2D models. The images that result from inverting these synthetic data indicate that the vertical resolution of the method is better than the horizontal, increasing the noise decreases the image resolution, and incorporating a priori knowledge in the form of positivity constraints improves the results. Although higher operating frequencies are usually associated with better resolution, frequencies as low as 100 Hz can produce acceptable images in simulated oilfield environments.

• Sponsoring Organization: USDOE
• DOE Contract Number: AC03-76SF00098; AC04-94AL85000
• OSTI ID: 136693
• Journal Information: Geophysical Prospecting, Journal Name: Geophysical Prospecting Journal Issue: 7 Vol. 43; ISSN GPPRAR; ISSN 0016-8025
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
ELECTROMAGNETIC SURVEYS
ENHANCED RECOVERY
IMAGE PROCESSING
MONITORING
OIL WELLS
WATERFLOODING
WELL STIMULATION