摘要 |
<p>A method for determining a diameter of a wellbore includes inducing an electromagnetic field in the wellbore and a formation surrounding the wellbore from a first location along the wellbore. At a first time, a phase and/or amplitude is measured, with respect to the field at the first location, of a signal induced by the electromagnetic field at a second and at a third location axially spaced apart from the first location and from each other. The inducing and measuring are repeated at a second time, and a resistivity of the formation, and the wellbore diameter at the first time and at the second time are determined from the measurements made at the first and at the second times. Any ambiguity in the resistivity is resolved by using resistivity determined from the measurements made at the first time.</p> |