Automatic dip picking from wellbore azimuthal image logs

摘要

Method for automatically determining a planar event such as a bedding plane from azimuthal wellbore log data (501). The image log may optionally first be filtered using a smoothing filter (502). Then, the image log is inputted to a gradient (first-derivative) filter (503). The image log is also used to find the optimal local sinusoidal trend (or orientation) on the image by determining the best sine wave at each depth among all azimuthal curves from the image using a minimum-variance method (504). Finally, bed boundaries are located based on highest contrast (506) calculated along the sinusoidal lines on the gradient image (505).

主权项

1. A method for determining a bedding surface from an azimuthal image made from a signal provided by a logging tool placed in a cylindrical wellbore, said method comprising:
determining, using a computer and based on minimum variance, a best sine wave in the the minimum variance represents a minimum value in a variance map of sine waves of the azimuthal image; computing contrast at each selected depth along the best sine wave in the azimuthal image; and locating one or more bedding surface boundaries at one or more depths with highest contrasts.