Dope for 9-5/8" (BTC) casing for gas tight application - Any experiences?
28 September 2009
I am currently investigating possible options for the use of pipe dope in achieving gas tight seals on 9-5/8" casing strings with BTC connections to be used on gas-lifted wells. BTC connectors as we are aware, do not possess the requisite metal-to-metal seal to achieve gas tight connections but I would like to know if there is any experience on this forum as regards the use of BTC casing connectors in gas tight applications.
Your responses would be highly appreciated.
DeepWater Team, Addax Petroleum, Lagos, Nigeria
Abe - the short answer is: gas-tight sealability is not possible with thread dope because BTC is not a full-inteference thread, nor does it have a seal shoulder or other full contact seal characteristic.
So, you can use a thread locking conmpound, or install a ring groove, or some other option, all of which have pluses and minuses. Or just go with a gas-tight connection.
Thanks very much for the suggestions.
I will definitely look into them.
You should contact Apache in the North Sea as the Forties Field was developed with gas lift and buttress casing. They would have extensive knowledge of any problems encountered over the last 30 years.
I know of two possible solutions.
1. Texas Aria and GB Tubulars can offer a modified BTC with a seal ring in the coupling.
2. Alternatively you can look at Seal-Lube (from Hunting) which will give a gas tight seal but you have to put it on the coupling end prior to coupling makeup.
Well Ops Mgr, ENI Brazil