2D Acoustic Time Domain Full Waveform Inversion - A Broadband Application in the Carnarvon Basin, Australia
P.J. Wellington, R. Brossier, S. Garambois and J. Virieux
Event name: 77th EAGE Conference and Exhibition 2015
Session: Full Waveform Inversion IV
Publication date: 01 June 2015
Info: Extended abstract, PDF ( 881.18Kb )
Price: € 20
We present an application of Acoustic Full Waveform Inversion to a 2D Line that crosses the North-Western Australian Continental Shelf Margin. The line was acquired by CGG using a Broadseis acquisition system. The line intersects two previously discovered gas fields. A "kinematically crude" initial model was constructed using Migration Velocity analysis. Results from Kirchhoff PreSDM using this initial model showed that significant residual moveout existed in the overburden and at the target level on our common image gathers (CIGs). 2D Acoustic Full Waveform inversion was used to update this initial model using a time domain forward modelling and inversion workflow. A number of strategies have been implemented to successfully perform FWI on this real dataset, including: source estimation strategies, multi-scale inversion, event windowing and a dynamic amplitude correction to account for the invalid acoustic assumption used in the modelling. The kinematically improved velocity model showed dramatically improved alignment of PreSDM common image gathers both in the overburden and at the target level of the two gas fields.