Patent ID: 6038513
Filing Date: 2000-03-14
Classification: E21B

Abstract:
An apparatus for estimating the ellipticity of an earth borehole using a rotating tool, said tool comprising:(a) acoustic sensors spaced peripherally around said tool at multiple sensor locations for generating standoff signals representative of at least three respective standoff distances from said sensor locations to at least three respective points on the wall of said borehole at a plurality of measurement times;(b) a circle calculator in communication with said acoustic sensors for receiving said standoff signals and generating a radius signal representative of the radius of a circle defined by said at least three points on the wall of said borehole for each of said measurement times;(c) a statistical calculator in communication with said circle calculator for receiving said radius signal for each of said measurement times and generating a statistical signal representative of at least one statistic of said radii;(d) an ellipticity calculator in communication with said statistical calculator for receiving said statistical signal and generating an ellipticity signal representative of the ellipticity of said borehole based on said at least one statistic; and(e) at least one data disposition device in communication with said ellipticity calculator selected from the group consisting of (i) a data storage device for receiving said ellipticity signal and storing ellipticity data representative of the ellipticity of said borehole, and (ii) a data transmitter for receiving said ellipticity signal and transmitting said ellipticity signal to the surface.