Failure Analysis of Tubing Collapse in a Gas Well

Table 5

Microstructure examination results of the failed tubing and the same batch of tubing without failure.

Sample position	Nonmetallic inclusions								Microstructure	ASTM grain size
	A		B		C		D
	Thin	Thick	Thin	Thick	Thin	Thick	Thin	Thick
Failed pipe body	0.5	0	0.5	0	0	0	1.0	0	Tempered sorbite (Figure 5)	9.5
The tubing body in the same batch	0.5	0	0.5	0	0	0	1.0	0	Tempered sorbite (Figure 5)	9.5