Observing fracture lineaments with Euler curvature

Abstract

In the last several years, seismic-curvature attributes have been shown to be very useful in delineation of folds, flexures, and faults. Although many curvature measures have been introduced, the most-positive and most-negative principal curvatures (k1 and k2) are found to be the most useful. All other curvature measures can be derived from the two principal curvatures. For example, the components of apparent curvature projected parallel to the dip azimuth and strike of a dipping plane are useful in given tectonic and stress settings. Euler curvature is a generalization of the dip and strike components of curvature in any user-defined direction, as applied to the interpretation of surface-seismic data. This attribute is useful for interpretation of lineament features in desired azimuthal directions, for example, perpendicular to the minimum horizontal stress. If a given azimuth is known or hypothesized to be correlated with open fractures or if a given azimuth can be correlated with enhanced production or effective horizontal drilling, a Euler-curvature intensity volume can be generated for that azimuth, thereby high-grading potential sweet spots.