Cause Analysis on Tripping of Tubing in a Well of Tarim Oilfield

Macroscopic examination, size measurement, chemical composition analysis and metallographic examination were used compositively to investigate the reasons for the tripping of tubing in a well of Tarim oilfield. The results indicated that wrong thread engagement was formed during the making up. Once wrong thread engagement appeared, the tension strength of tubing connection would be reduced greatly, and tripping could take place when the tubing string was lifted up.