A New Magnetic Detector for Inspection of Defects in Oil Well Tubing

In oil wells, tubing suffers from pitting corrosion, relatively large areas of corrosion, rod wear, etc. In some cases, these defects can result in a physical separation of the tubing′s body wall during the production process. For this reason, tubing lifetime prediction based on in situ inspection and monitoring of tubing conditions is of particular importance. A new magentic detector for inspection of above defects is presented. The detector employs hardware redundant technology, magnetic concentrating technology, and some special technologies of multiple probes such as automatic opening and closing, control of drifting, and servocontrol to perform the inspection of above defects simultaneously. Furthermore, the linear relationship between the detector output and the residual cross sectional area of oil well tubing is theoretically established. The test results show that the detector has specific advantages such as high resolution, hig stability, high reliability, simple structure, and high adaptable to in situ conditions.