Structural curvature versus amplitude curvature

Abstract

Because they are second-order derivatives, seismic curvature attributes can enhance subtle information that may be difficult to see using first-order derivatives such as the dip magnitude and the dip-azimuth attributes. As a result, these attributes form an integral part of most seismic interpretation projects. This conventional computation of curvature may be termed as structural curvature, as lateral second-order derivatives of the structural component of seismic time or depth of reflection events are used to generate them. In this study, we explore the case of applying lateral second-order derivatives on the amplitudes of seismic data along the reflectors. We refer to such computation as amplitude curvature. For volumetric structural curvature we compute first derivatives in the inline and crossline components of structural dip. For amplitude curvature, we apply a similar computation to the inline and crossline components of the energy-weighted amplitude gradients, which represent the directional measures of amplitude variability. Because of limits to lateral resolution, application of amplitude curvature computation to real seismic data results in greater lateral resolution than structural curvature. The images are mathematically independent of each other and thus highlight different features in the subsurface, but are often correlated through the underlying geology.