Importance of anisotropic rock physics modelling in integrated seismic and CSEM interpretation

摘要

Shale comprises about 75% of the clastic fill of sedi-mentary basins (Jones and Wang, 1981). Shales in particular tend to exhibit high levels of elastic and resistivity anisotropy (Ellis et al., 2010a). The degree of anisotropy depends on the type and volumetric fractions of the constituents of the rock and on the size and orientation of rock fabric heterogeneities compared to the length scale of measurement. The effective elastic and electrical proper-ties of rocks depend on the volumetric fractions of the rock's solid and fluid constituents and on the rock's microstructure. Different constituent and microstructural features affect elas-tic and electrical properties in different ways and to varying degrees. For instance, the difference in the elastic properties of a host solid matrix with connected and disconnected con-ductive fluid fractures is not as large in a relative sense as the difference in electrical resistivity, where fluid connectiv-ity is one of the most significant controlling parameters. On the other hand, a small amount of initial grain cement does affect electrical properties, but not to the same extent as it affects elastic properties.