Geophysical inversion for contact surfaces

Applications of boundary-preserving seismic tomography for delineating reservoir boundaries and zones of CO2 saturation

“…Nevertheless, the smooth model is not always the best model for geologic structures that are commonly characterized by sharp boundaries and comprise distinct geologic bodies, for example, the sharp petrophysical boundaries between the host rocks and the hydrocarbon reservoir zones (Michelena and Harris, 1991; boundary-preserving regularizations have been developed in image reconstruction to restore sharp edges and high-contrast images (Charbonnier et al, 1997). Some schemes have been applied to geophysical data, for example, the compactness body constraint (Last and Kubik, 1983;Ajo-Franklin et al, 2007), the L p -norm (Claerbout and Muir, 1973;Bube and Langan, 1997;Farquharson, 2008;Zhang and Castagna, 2011;Li et al, 2012;Zhang et al, 2013), total variation regularization (e.g., Farquharson and Oldenburg, 1998), the minimum gradient constraint (Portniaguine and Zhdanov, 1999;Abubakar et al, 2008), and the level-set method (Lelièvre et al, 2012;Li and Leung, 2013;Zheglova et al, 2013;Li et al, 2014). Among them, the minimum gradient support (MGS) regularization proposed by Portniaguine and Zhdanov (1999) tends to produce more blocky models because it selects models where the spatial gradients of an anomaly, rather than the anomaly itself, are compact.…”