Hydrates in SCSSV Control Lines

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Suncor, operator of the Terra Nova subsea field offshore canada has had increasing frequencies of hydrates in SCSSV control lines. To date we have had 6 wells that have required remediation.  

All SCSSV's are Halliburton 7" SP2 Valves. The lastest challenge is a hydrate in a gas injection well SCSSV control line that has failed to clear using an Oceaneering ROV vacuum skid previously used with success on high GOR producing wells with similar issues.

1) Interested in other operators challenges around hydrates in control lines and what operating procedures have been modified, if any, to address the issue. Ie. Well Shut in protocols, HP supply pressure management/ min hold open pressure, etc.

2) General comments on SP2 reliability in this regard. Experience in both the upper and lower SP2 MTM seals leaking and/or dynamic seals leaking, allowing gas to migrate into the contol line.

3) Feasability of longterm injection while SCSSV not open /protected by flow tube. Unknown position of flapper and wear and fatigue load to flapper hinge pin. Injection rates are typically 2.4 MMscm/d to 3.6 MMscm/d through 7" completion.

Appreciate any input or similar expereinces.
asked May 7 in COIN by Barry LeMoine (120 points)

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