Treating seismic data to estimate time lag due to speed anisotropy in underground formation comprises grouping data and inter-correlating selected traces in selected time windows

摘要

The data is treated by grouping it and inter-correlating the selected traces in selected time windows to estimate the time lag due to a speed anisotropy in the underground formation. The seismic traces in the grouping are adjusted by the value of the time lag estimated from the selected traces. The variation of amplitude with the angle of incidence and with the azimuth are analyzed for the adjusted traces using least squares analysis. Successive traces are intercorrelated to estimate the time lag due to a speed anisotropy by a least squares analysis to calculate variation of speed with azimuth in the traces. These results are applied to the seismic data and a further least squares analysis is applied to the reflection coefficient, the angle of the source and receiver and the angle of incidence to calculate variations in amplitude with azimuth. The errors in calculation of speed are also estimated using least squares analysis. An Independent claim is included for a computer with a programme to execute the above analysis or a device that can be linked to a computer to execute the above analysis.