US Patent 7698937 Method and apparatus for detecting defects in oilfield tubulars

A sensor system for detecting defects in a tubular string while positioned in the well includes a sensor tool (10) comprising a plurality of circumferentially spaced sensors (40) arranged in two or more axially spaced rows. A plurality of sensors are positioned in each row, with each sensor positioned on one of a plurality of sensor support pads. Sensors within a row may include sensors with axes inclined at different angles, and each of the plurality of sensor pads may move from a radially retracted run-in position to a radially extended sensing position. A flexible line (50) may be used for lowering a sensor tool in the well and retrieving the sensor tool from the well.