Is it necessary to install a downhole safety valve in a subsea ... - NTNU
Is it necessary to install a downhole safety valve in a subsea ... - NTNU
Is it necessary to install a downhole safety valve in a subsea ... - NTNU
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<strong>Is</strong> <strong>it</strong> <strong>necessary</strong> <strong>to</strong> <strong><strong>in</strong>stall</strong> a <strong>downhole</strong> <strong>safety</strong> <strong>valve</strong> <strong>in</strong> a <strong>subsea</strong> oil/gas well?<br />
19 6 MORE The runn<strong>in</strong>g speed of the<br />
riser/BOP is <strong>to</strong>o high<br />
20 6 PART The riser eleva<strong>to</strong>r is<br />
OF jammed<br />
21 7 NOT The riser eleva<strong>to</strong>r is<br />
broken<br />
22 7 LESS The assembly is lowered<br />
<strong>to</strong> slow<br />
23 7 MORE The assembly is lowered<br />
<strong>to</strong> fast<br />
24 7 LESS Riser is not properly<br />
connected<br />
Caus<strong>in</strong>g the drill<strong>in</strong>g deck <strong>to</strong><br />
crack and the BOP may<br />
sw<strong>in</strong>g and cause oscillat<strong>in</strong>g<br />
The assembly can not be<br />
lowered <strong>to</strong> the seabed<br />
The assembly can not be<br />
lowered <strong>to</strong> the seabed<br />
Caus<strong>in</strong>g the procedure <strong>to</strong> last<br />
<strong>to</strong>o long<br />
May cause the str<strong>in</strong>g <strong>to</strong> jerk<br />
when s<strong>to</strong>pped <strong>to</strong> connect a<br />
new riser pipe and the<br />
assembly may sw<strong>in</strong>g<br />
The riser is not screwed<br />
properly on. The BOP<br />
assembly may fall down<br />
25 7 MORE Riser is screwed <strong>to</strong> tight Threads are damaged and<br />
may not hold the assembly as<br />
<strong>in</strong>tended. BOP may fall<br />
26 7 NOT New riser pipes are not<br />
present<br />
27 9 LESS The guidel<strong>in</strong>es are not The BOP is not <strong>in</strong> the right<br />
tightened enough<br />
28 10 MORE The BOP is attached <strong>to</strong><br />
the Wellhead w<strong>it</strong>h <strong>to</strong><br />
much force<br />
29 10 NOT The BOP is not <strong>in</strong><br />
pos<strong>it</strong>ion w<strong>it</strong>h the<br />
Wellhead<br />
Diploma thesis, <strong>NTNU</strong> 2002<br />
F<strong>in</strong>d a runn<strong>in</strong>g speed that is<br />
ideal for this operation<br />
Make sure eleva<strong>to</strong>r is<br />
function<strong>in</strong>g prior <strong>to</strong> operation<br />
F<strong>in</strong>d a runn<strong>in</strong>g speed that is<br />
ideal for this operation<br />
F<strong>in</strong>d a runn<strong>in</strong>g speed that is<br />
ideal for this operation creat<strong>in</strong>g<br />
a smooth s<strong>to</strong>p when<br />
connect<strong>in</strong>g new pipes<br />
Use <strong>in</strong>struments <strong>to</strong> measure the<br />
<strong>to</strong>rque and pos<strong>it</strong>ion<br />
Use <strong>in</strong>struments <strong>to</strong> measure the<br />
<strong>to</strong>rque<br />
The operation is delayed Make sure that enough riser<br />
pipes are present<br />
pos<strong>it</strong>ion<br />
Stabs, AX-seal and lock<strong>in</strong>g<br />
screws are damaged.<br />
The BOP may not connect <strong>to</strong><br />
the wellhead due <strong>to</strong> wrong<br />
pos<strong>it</strong>ion<strong>in</strong>g<br />
Make sure the connection of<br />
the BOP is nice and steady<br />
Use <strong>in</strong>struments <strong>to</strong> measure the<br />
exact pos<strong>it</strong>ion<br />
50
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