Paper: Advanced Electromagnetic Tubular Inspection During Well Services

"The Wellhead Scanalog is a new and effective approach to the evaluation of used oil field tubing. Designed to perform tubular inspection while the tubing is being pulled, it does not interfere with normal workover operations. The tool provides four non-destructive methods to detect and evaluate used tubing defects such as rodwear, corrosion pitting, erosion, holes, and splits. A new rotating magnetic field technique is used for rod wear, a modified flux leakage technique is used for pitting, and average wall measurements derive from a total flux concept. Eddy currents are used for holes and splits. Radiation techniques are not used for safety reasons. Sensing systems are non-contract, and not affected by scale, mud, paraffin and water, and there are no active or moving parts in the sensor package. The tool bolts directly onto the well head, and in many fields several wells can be inspected each day. Sequential inspection of tubes in over 5000 wells inspected has revealed well tubing profiles which provide useful diagnostic information for well servicing programmes."