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Geostatistical Simulation of Acoustic Log Data for Seismic Depth Conversion

Journal Article · · Natural Resources Research (New York, N.Y.)
; ;  [1]; ;  [2]
  1. UFRGS, Mining Engineering Department (Brazil)
  2. Now Geophysical Resources and Services, Formerly Xstrata Inc (Australia)

Seismic reflection methods measure the time a seismic wave takes to travel through the ground, from the user defined source to a series of signal monitoring sensors known as geophones. The measured times need to be depth converted to allow for integration with other geological data. In order to convert from time to depth, an estimate of the rock volume velocity field must be made. The velocity field estimate can be made by assignment of velocity estimates to a geological model independent of the seismic processing. This article presents the results of using the acoustic geophysical log data extrapolated via sequential Gaussian simulation to derive the velocity field. The uncertainties associated with the velocity estimates were significant and provided the means to assess confidence limits for the actual depth determination. The technique is assessed by application to a major coal deposit, approximately 2.1 m thick and 210 m deep. Considering only the uncertainty associated with estimating the velocity field, half of the confidence interval values showed approximately 1 m of uncertainty in depth. The application of sequential Gaussian simulation to model the 3D distribution of acoustic velocity can be extended to other geophysical log parameters or derived estimates.

OSTI ID:
21064177
Journal Information:
Natural Resources Research (New York, N.Y.), Journal Name: Natural Resources Research (New York, N.Y.) Journal Issue: 4 Vol. 16; ISSN 1520-7439
Country of Publication:
United States
Language:
English

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