Electromagnetic Corrosion Detection Sensor

Abstract

Oil flowlines are connected to the well, exposing them to temperatures that range from 130℃ to 150 ℃ and a pressure range from 750 psi to 3000 psi. These extreme conditions accelerate corrosion reactions and cause monthly accidents, which means financial losses and safety risks. The annual cost due to corrosion is calculated to be about US$1,372 billion. Corrosion inspection and management is key to reduce the expenses and improve safety. The most used inspection devices are the pipeline inspection gauges (PIGS). They are inserted through launcher stations into the pipeline and leave at retrieval stations. However, oil flowlines have diameters ranging from two to twelve inches which cannot accommodate the size of PIGS. The absence of the launcher and retrieval stations in the oil flowlines makes it also unfeasible. The other inspection techniques also suffer from serious disadvantages such as being destructive, ineffective with insulation layers and build up layers, etc. A previous work done by the previous graduate student measured the change in the magnetic force with a load cell between a permanent magnet and the surface of the pipe due to material loss. The device was able to detect material loss when the pipe thickness has reached 7.7 mm or lower for an ASTM A36 carbon steel specimen. However, the permanent magnet sensor is difficult to install given that the magnitude of the attractive force could pull the installer towards the pipe. In addition, most permanent magnets can endure up to 80℃ before losing their magnetism, which is lower than pipeline temperatures. Most importantly, there is a maximum magnetic field intensity for permanent magnets which limits its applications. Therefore, this work replaces the permanent magnet with an electromagnet to improve installation of the device and increase corrosion detection thickness to higher than 7.7 mm. This work includes numerical simulations (MATLAB & Maxwell) and experimental testing.

Date of Award	May 2022
Original language	American English