Wave-Equation-Based AVO Inversion in the Presence of Coal Seams. A Synthetic Study from the Cooper Basin, Australia
D. Gisolf, P. Haffinger, P. Doulgeris and S. Squire
Event name: 80th EAGE Conference and Exhibition 2018
Session: AVO/AVA Analysis - Case Histories
Publication date: 11 June 2018
Info: Extended abstract, PDF ( 816.95Kb )
Price: € 20
Coal seams, being very soft and light, cause strong internal multiple reflections and mode-conversions, as well as strong transmission effects. Conventional AVO inversion based on primary reflection coefficients only, will not be able to distiguish the primary from the multiple energy and consequently produce spurious results. Wave-Equation-Based AVO inversion, being based on the full elastic wave-equation, is able to account for all these effects and image the coal seams properly. Like all other AVO techniques, the WEB AVO is applied in the 1.5D data domain. In this paper we consider the logs from the well Moonanga-1 in the Cooper Basin in South Australia. This area is notorious for the presence of coal seams, hampering seismic interpretation. Full elastic synthetics are produced from the logs. The results from conventional Sparse-Spike-Inversion and from WEB inversion of the synthetic gather are compared, showing a clear improvement for the WEB inversion. This will lead to much better interpretability of the inverted data.