ABSTRACT
Variations of dip from point to point in the subsurface and variations in the angle of dip as a function of azimuth of dip are related to the bulk curvature of the structural setting. The bulk curvature and related transverse and longitudinal structural directions of any well’s setting can usually be determined by statistical curvature analysis of the well’s dipmeter data. The bulk curvature can be assigned to one of four general categories: planar, singly curved, plunge reversal, or domal bulk curvature. Structural bulk curvature and related transverse and longitudinal structural directions provide the means for extracting “true structural dips” from erratic or ambiguous dipmeter data. They also provide the means for calculating the bearing and plunge of crestal and trough lines of folds—finding the strike and dip of crestal, axial, and inflection planes of folds—and the strike and direction of dip of dip-slip faults. These capabilities can usually be used to draw partial maps and cross sections centered at the well. A field example shows how the three-dimensional geometry and productive limits of the doubly plunging Railroad Gap field in California could have been predicted from the dipmeter data of the discovery well.
