Magnetic detection technique for double-layer steel tubing and casing damage

摘要

Oil tubing and casing damage often occurs during oil and gas field operations. Therefore, a non-destructive damage detection method that is easy to implement and does not affect field operations is necessary. In this study, a magnetic detection technique was applied to conduct non-destructive examination of double-layer steel tubing and casing based on geomagnetic field magnetisation. Detection effects under various defect combinations were investigated. Through this method, the detection signals were analysed and processed for defect localisation and quantification. As the thickness of the tubing and casing walls gradually decreased, the collected magnetic flux density increased. The thickness distribution of the tubing corrosion wall was obtained from the magnetic induction strength via least squares fitting. The relative error of the wall thickness measurement was less than 10% and the magnetometric sensor exhibited remarkable dynamic repeatability.