Geosteering Phase Attributes: A New Detector for the Discontinuities of Seismic Images

Traditional 1-D instantaneous phase (IP) is a routine attribute for detecting structural discontinuities of seismic images. The phase attribute has the ability to detect subtle changes, but it is meanwhile sensitive to noise. Furthermore, the traditional IP attribute is calculated trace by trace and thus cannot effectively utilize geological constraints. The sensitivity of noise and unavailability of geological constraints limit the practical applications of IP attributes. To address these two issues, this letter proposes a 3-D geosteering phase attribute derived from IP. At first, we implement the local stack on IP traces along both the time direction and the trajectory direction of the events to construct new stacked phase traces. Then, we compute the covariance of neighboring stacked phase traces along different spatial directions and extract the directional phase information from the resulting complex-valued covariance. Finally, we derive the so-called geosteering phase attributes by taking the maximal value among the extracted directional phases to approximately characterize the discontinuity measurement perpendicular to the structural trend in a 3-D curved plane. The examples including 3-D synthetic, physical modeling, and real seismic images are adopted to demonstrate the effectiveness of the proposed geosteering phase attributes. The results illustrate that the new geosteering phase attributes can be used as an effective and robust tool for the automatic detection of faults, channels, and even large-scale fracture groups.