Geophysics

Coherence and curvature are iconic attributes now commonly available on most interpretation workstations that help characterize small- and large-scale faults, large fractures, pinch-outs, buried channels, reef edges and unconformities. The quality of both these attributes, among other factors, relies on accurate estimates of volumetric dip. Coherence, amplitude gradients and GLCM texture attributes should be computed along structural dip, while curvature is computed from volumetric estimates of structural dip. Due to differences in both resolution and sensitivity to coherent noise, different frequency components might exhibit different dip. Such awareness has led to the development of multispectral coherence that makes use of summation of covariance matrices of individual spectral components, rather than just the covariance matrix computed from broadband seismic data.

The bandwidth of a signal is a measure of the breadth of its spectrum, often expressed as the distance measured in Hertz between the half-power points of a smooth spectrum. Bandwidth is the best measure of resolution. Although first introduced to the seismic community in the 1970s, only a limited number of published papers show the value of this attribute. In this column, we show the value of bandwidth when applied to data from the Utica area of Eastern Ohio, United States and from the Gulf of Mexico.

With the advent of 3-D seismic technology and its remarkable spatial resolving power, mass transport deposits are better defined in terms of their full areal extent and their morphologic features in areas affected by slope failure. Though mass movements have been extensively studied within the Permian Basin, little work has been published on the nature of these MTDs and their related geomorphological expression on seismic. The goal of this study is to understand sediment flow and delineate the anatomy of the MTD that was deposited 275 million years ago in the Midland Basin. This feature was deposited in the Upper Leonard interval which overlies the Upper Spraberry formation.