User Manual
Turnaround Sheave
108-3108- HV0
108-3108-HV1
OPS-3108 Rev E
A-5
Critical Lengths
Using the equations above we can determine the maximum safe riser length (
llll
) that can be deployed with a given line pull (P) for a
know well head pressure accounting for the bending caused by the turnaround sheave
Maximum Riser Length l(m)
P (Ton)
1
2
3
4
5
6
7
8
9
10
W
e
ll
H
e
a
d
P
re
s
s
u
re
(
p
s
i)
0
38.5
26.1
20.6
17.3
15.0
13.3
12.0
10.9
10.0
9.2
100
29.8
22.4
18.4
15.7
13.8
12.4
11.2
10.3
9.4
300
28.0
21.3
17.6
15.2
13.4
12.0
10.9
9.9
500
26.5
20.4
16.9
14.6
12.9
11.6
10.5
700
25.2
19.6
16.3
14.1
12.5
11.2
1000
27.6
20.5
16.7
14.3
12.6
1250
No Buckling Region
28.5
20.6
16.7
14.2
1500
29.6
20.8
16.6
1750
31.2
21.0
2000
33.2
Table 10: Maximum Safe Riser Length for Given Line Pull
Conclusion
The critical length of risers has been established for the range of pulling forces that could be experienced. The equipment operation
instructions convey these limitations so that buckling is never experienced during operations.