Incremental depth measurement for real-time calculation of dip and azimuth

Abstract

The present invention provides a method and apparatus for logging an earth formation and acquiring subsurface information wherein a logging tool is conveyed in borehole to obtain parameters of interest. The parameters of interest obtained may be density, acoustic, magnetic or electrical values as known in the art. The parameters of interest are acquired with a plurality of sensors. For time based image data, the time separation values between signals acquired from separate sensors for individual subsurface features are determined. The time separation values may be determined using correlation or other methods illustrated herein or as known in the art. Using known sensor spatial separations and time separation values a drill rate is determined and an incremental depth for the subsurface feature is defined. The geometries of subsurface features in incremental depth relative to the well bore may be accurately determined, including extremely accurate dip and azimuth structural information relative to the borehole.