OIL AND GAS WELLS PRODUCTION TUBING ELECTROMAGNETIC FLAW DETECTION METHOD Russian patent published in 2018 - IPC E21B47/85 G01N27/72 

FIELD: defectoscopy.

SUBSTANCE: invention relates to the production tubing of oil and gas wells electromagnetic flaw detection method. Oil and gas wells production tubing electromagnetic flaw detection method includes the electromagnetic field excitation in steel production tubing, electromagnetic field signals measurement and processing, signals conversion into digital form, their transfer to the surface and computer processing. Electromagnetic field excitation is carried out by an electromagnet in two stages. At the first stage, supplying the 500–600 mA power supply current to the electromagnet, at which the metal complete magnetic saturation occurs over the entire thickness, performing the electromagnetic field measurement and recording. At the second stage, reducing the electromagnet power supply current to 100 mA, decreasing the metal thickness magnetic saturation, and performing the electromagnetic field measurement and recording. Then, performing the two recorded measurements comparison. At that, measurements of the electromagnetic field with a low power supply current give information about internal and through defects. Presence and nature of external defects is determined by subtracting of the electromagnetic field with a lower magnetic saturation recorded measurements from the electromagnetic field with complete magnetic saturation recorded measurements.

EFFECT: simplification of the defects detection and separation technology located on the production tubing inner and outer walls, ensuring high accuracy of defects detection and separation.

1 cl, 1 dwg