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Setting a TRSCSSSV at 4,500mTVD
11 December 2017
Dear members,

Our Petroleum Technologist wants to run 4-1/2” tubing instead of 3-1/2”. The problem is a 4-1/2”, 10kpsi TRSCSSSV will not fit in the already-installed 7” casing. He has suggested we run 4-1/2” tubing from surface and crossover to 3-1/2” just above the packer at 4,500mTVD. This would allow us to run a 3-1/2” TRSCSSSV at 4,500mTVD. My concerns are;-

 1)    Do TRSCSSSVs work on the end of a 4,500m control line?

2)    Are the closing / opening times much longer?

3)    Is this common? I have never heard of anyone setting a TRSCSSSV this deep

4)    What is the time to transmit pressure (or bleed-off pressure) along 4,500m of control line

Your comments and thoughts on this would be most appreciated, especially from anyone who has addressed and overcome this challenge.

Kind regards

Allan

2 answer(s)
KenHorne1
Multilateral Specialist
Multilateral Solutions
Total Posts: 32
Join Date: 30/09/13

Hi Allan.

I would be reviewing this firstly from a safety perspective.  If the SSSV is set at +/- 4500m then even when it is closed you will have the full inventory of fluids, gas and pressure that can still evacuate above the closed valve.

So in the nightmare scenario where the well head or tree is damaged or leaking, you will have the potential for the full 4500m of “fuel” escaping even with the valve closed.

Regards

Ken


John_McNab
Completions & Workover Manager
SPREADAssociates
Total Posts: 11
Join Date: 11/02/10
Allan,

1 You could check with your SSSV provider, but you may be able to do it with a balance line system. A normal single line SSSV would not work as the hydro-static head of the control line fluid would maintain the flapper permanently open.

2 Yes, just because of the volume of the control lines.

3 The deepest I have ever run one is ca 2,500 ft in a well with high CITHP - potential hydrate issues when shut in.

4 Pass! Would depend on the surface HPU pump.

I would suggest, assuming that equipment below the SSSV allows, that you "bottle-neck", which is something I have done before a couple of times inside 7" casing. 4 1/2" tubing below the tubing hanger, x-over to the 3 1/2" SSSV (at whatever depth is actually recommended) then back to 4 1/2" tubing down to above the packer, where you cross back to the 3 1/2" upper connection on the packer. 

As long as there is no need for anything larger than the SSSV ID below, then this should work. 

ATB

John
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