An efficient finite-difference approach for acoustic modeling in cased boreholes with micro-annuluses
- Yanyan Zhang (Southern University of Science and Technology, China) | Xinding Fang (Southern University of Science and Technology, China) | Yuandi Gan (Southern University of Science and Technology, China)
- Document ID
- Society of Exploration Geophysicists
- SEG International Exposition and Annual Meeting, 15-20 September, San Antonio, Texas, USA
- Publication Date
- Document Type
- Conference Paper
- 2019. Society of Exploration Geophysicists
- Effective, Borehole acoustics, Wave propagation, Finite difference
- 0 in the last 30 days
- 13 since 2007
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We propose an efficient and accurate finite-difference approach for modeling the acoustic wave propagation in cased boreholes with micro-annuluses. The presence of micro-annuluses at casing-cement or cement-formation boundaries can result in unconformities that can change the borehole acoustic response. Correction interpretation of the acoustic measurements acquired in such a downhole environment requires conducting numerical simulations to investigate the characteristics of borehole acoustic wave propagation. Traditional numerical methods that use very fine grid to model a micro-annulus are computationally expensive. Because the sonic wave wavelength is generally much larger than the aperture of a micro-annulus, the wave senses only the effective elastic response of a region adjacent to the micro-annulus. We propose to use an effective medium finite difference approach for modeling microannuluses in wave propagation simulations. In this approach, we model a micro-annulus as an effective thin layer embedded between the casing-cement or cement-formation boundaries. Comparisons with the results calculated using a fine grid finite difference approach for borehole models with different micro-annulus settings demonstrate that the proposed method is accurate and computationally efficient in modeling micro-annuluses.
Presentation Date: Monday, September 16, 2019
Session Start Time: 1:50 PM
Presentation Time: 2:40 PM
Location: Poster Station 4
Presentation Type: Poster
|File Size||1 MB||Number of Pages||5|
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