Patent ID: 8065085
Filing Date: 2011-11-22
Classification: E21B,G01V,G06F

Abstract:
1. An apparatus for use in a wellbore, the apparatus comprising: a downhole portion movable within the wellbore in a direction generally parallel to the wellbore; a first acceleration sensor mounted at a first position within the downhole portion, the first acceleration sensor generating a first signal indicative of a first acceleration in a first direction generally parallel to the wellbore at the first position; a second acceleration sensor mounted at a second position within the downhole portion, the second acceleration sensor generating a second signal indicative of a second acceleration in a second direction generally parallel to the wellbore at the second position; a bend sensor generating a third signal indicative of an amount of bend of at least a portion of the downhole portion; and a controller configurable to calculate a depth along the wellbore, a velocity along the wellbore, or both a depth and a velocity along the wellbore of the downhole portion in response to the first, second, and third signals, and independent of errors from wire-line depth, wire-line velocity, or pipe tally depth measurements.