Patent ID: 8571796

Claim:
A method of determining a rate of penetration and/or rate of rotation of a drilling assembly or logging tool while drilling or logging a wellbore, the method comprising the steps of: at a first time instant, acquiring and storing a first logging data frame using a first array of sensors, and at a second time instant, acquiring and storing a second logging data frame using a second array of sensors, wherein the second logging data frame overlaps at least partially the first logging data frame, and wherein the method further comprises the steps of: comparing the first and second logging data frames, determining a relative change in depth and/or azimuth between the first and second logging data frames, calculating the rate of penetration and/or rate of rotation based on the relative change in depth and/or azimuth determined and a difference between the first and second time instants, wherein the logging data relate to at least one property of a zone surrounding the wellbore.