CUSTOMER: Shell Expro, Brent Bravo platform

PROBLEM: Two 36" pig launcher valve bonnet o-rings required strengthening on Brent Bravo offshore platform.  Using conventional techniques (changing the valve out) three platforms in the field (Bravo, Charlie and Delta) would have had to be shut down for approximately 10 days at considerable cost.

SOLUTION:  Furmanite was called in to strengthen the o-rings, but had to complete the work within a 24 hour timescale, in order to maintain contractual gas delivery from the field, as well as working in extremely tight and hazardous conditions. Extensive workshop trials were carried out, involving a 40 ft refrigerated truck and a 48 hour chill down, for accurate simulation of the real temperatures faced on the Brent platform. This enabled a full-scale timed trial to take place, ensuring that the required results could be achieved. 

Knowing that a large proportion of the 24 hours would be taken up by the depressurising and pressurising phases, the company developed a special fast-curing sealant, dramatically reducing the curing time from the usual 12 to 16 hours, to just four hours.  A purpose-designed jig piece and clamping arrangement were also designed and manufactured to perform in the circumstances that Furmanite would be faced with on the platform.

The initial phase involved drilling down some 10 inches through the valve bonnet to hit the o-ring cavity location precisely, but falling short of the final breakthrough by a pre-set distance was achieved in just four hours (less time than anticipated) using Furmanite’s specially manufactured equipment

The crucial second, 24 hour, phase involved breaking through the remaining metal into the o-ring cavity, injecting the special sealant, and achieving the shortened cure.

OUTCOME: The technology and its application was planned perfectly so that it was not only fast, but also safe and lasting, saving in the region of £15 million for Shell Expro.