Inversion Of Travel Time For Velocity
Name
1983.7 Willis.pdf
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595.44 KB
Format
Adobe PDF
Checksum (MD5)
c1336533b35565a4e5f23b125ed0c05c
Author(s)
Willis, M.E.
Date Issued
1983
Publisher
Massachusetts Institute of Technology. Earth Resources Laboratory
Series/Report no.
Earth Resources Laboratory Industry Consortia Annual Report;1983-07
Abstract
Common source velocities and borehole compensated (BC) estimates have been used to obtain formation velocity estimates from full waveform acoustic
logs (Willis and Toksoz, 1982). With both of these methods the receiver
separation of the tool dictates the depth resolution of the velocities
determined. This paper presents a method to 1) increase the depth resolution
of the velocity estimates, and 2) remove the effects of a changIng borehole radius upon the velocity estimates through formal inversion of arrival times and
travel time moveouts. Results obtained by the inversion of full waveform acoustic log travel times appear quite promising. The velocity estimates on synthetic arrival times are slightly more noisy than those obtained using the standard BC technique. The most significant aspect of synthetic arrival times is
that they generally appear to be unbiased. The BC technique is biased around formation boundaries and is especially biased for thin layers.
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