Patent ID: 8117907
Filing Date: 2012-02-21
Classification: E21B

Abstract:
1. A downhole logging while drilling tool comprising: a substantially cylindrical tool body configured to be connected with a drill string, the tool body having a longitudinal axis; at least first, second, and third ultrasonic sensors deployed in the tool body, at least the first of the ultrasonic sensors being configured to (i) transmit ultrasonic energy into a borehole and (ii) receive reflected ultrasonic energy from a borehole wall, at least a second and a third of the ultrasonic sensors being configured and disposed to receive the reflected ultrasonic energy transmitted by the first ultrasonic sensor; and a controller including instructions for estimating an eccentricity of the logging while drilling tool in a borehole from a difference or a ratio between the reflected ultrasonic energy received at the second transducer element and the reflected ultrasonic energy received at the third transducer element.