Technology for Monitoring the Wear and Defect of Casing and Tubing for Multistring Wells by the Method of Transient Processes

A brief overview of the current state of electromagnetic flaw detection and thickness measurement of casing strings and tubing in multistring wells is given. The article presents a novel technology for monitoring the technical condition of multistring wells and descripts the MID-5 equipment and interpretation methods using the knowledge base. Based on the measurement results on physical models simulating various defects in the third, fourth and fifth casings, the capability of the developed tool was assessed. Research examples in production wells are show the effectiveness of magnetic-pulse detection in monitoring the safe operation of wells. Validated models of multistring (three to five) wells were used for measurements to assess the tool's performance as well as the error in wall thickness calculation. It is shown that the maximum absolute error for the four- and five-casing model does not exceed 1.4 mm. The electromagnetic flaw detection technology via the transient process method has been used to test multistring wells in Russia, the Middle East, northern Europe, North America, Malaysia, including offshore wells, and shows the possibility of identifying damage to the integrity of casing strings.