Experimental Study on Sealing Failure Mechanism of Injection-Production String in Underground Gas Storage under Cyclic Loading

Table 1

Gas seal detection of tubular string thread in domestic gas storage.

Name of gas storage	Type of string	Size of string (mm)	Steel grade of string	Type of thread	Number of test buckles	Number of leakage buckles	Passing rate (%)
XN	Tubing	114.3	4 ½ VM80S + 3 ½ N80EUE/TP90S	VAM-TOP	239	1	99.6
	Intermediate casing	244.5	TP95S	TPCQ	369	6	98.4
		339.7			292	8	97.3
	Suspension casing	177.8	TP95S	TPCQ	140	0	100
		244.5			221	5	97.7
	Tie-back casing	177.8	TP95S	TPCQ	302	6	98.0
		206.4	VM95SS	VAM-FJL	16	1	93.8
		244.5	TP95S	TPCQ	290	12	95.9
XB	Production casing	177.8	VM125HC	VAM-TOP	382	24	93.7
	Suspension liner	139.7	HP1–13Cr110	BEAR
DL	Production casing	177.8	N80 + L80	BGC	1711	14	99.2
	Intermediate casing	244.5	N80		1300	15	98.8
DG	Intermediate casing	273.1	N80	TPCQ	837	1	99.9
	Suspension liner	177.8	P110		320	0	100
	Tie-back casing				760	0	100
SB	Suspension liner	177.8	P110	BGC	13	1	92.3
	Tie-back casing
CQ	Casing	177.8	95S + TN110 Cr13S	TSH-3SB	350	20	94.3
		241.3			321	13	96.0