Estimating based on downgoing waves in VSP data can be challenging when scattered waves from near-borehole velocity/density anomalies interfere constructively and destructively with the direct arrivals. The wavefield interference leads to modulations in amplitude spectra and these undesired spectral changes result in over- and/or under-estimates of values. In order to improve the reliability and accuracy of estimates, we propose locating such scatterers and mitigating their effects from the spectra by combining waveform modelling and adaptive subtraction. We investigate this wavefield interference phenomenon and test our proposed method using a zerooffset VSP field dataset from offshore Australia and synthetic data created based on well logs in the area.
Presentation Date: Wednesday, September 18, 2019
Session Start Time: 8:30 AM
Presentation Start Time: 10:35 AM
Location: 303B
Presentation Type: Oral
