A Tale of Two Capping Stacks
The capping stack above consists of two-inch O.D. line pipe screwed into a flange half, a flange-to-flange top half screwed into a 150 PSI rated ball valve and another 2-inch line pipe flange with 1/2 bolts to the production tree, seen below. It's rated to 150 PSI but if the FTP below this stack was 90 PSI and you had to shut the well in, you'd close the handle and take cover behind the closest house.
To date this water well is the biggest onshore, and off, thankfully, blowout in the Republic of Guyana in eastern South America. It occurred in 2018, in somebody's back yard, caused quite a mess, and upset a lot of the neighbors when it cratered and mud flowed down the street into flowerbeds and swimming pools.
Believe it or not Exxon engineers were indirectly involved in the kill procedure, not kidding:
This stack required no spin bolt, no snub lines and no well control company from Houston flying down in a Citation. Hands got a little wet, that's it. The same hands then started pressure washing nearby homes and giving baths to neighborhood cats.
The capping stack above is 18 3/4-15K PSI stack (Trendsetter) used on the Macondo well in the summer of 2010. Its hanging in the pool of the Transocean Discover Inspiration being readied for the riser run, 5,000 feet below.
It has a three-ram BOP, doubled drilling valves, choke lines, a hydraulic activated choke package, diverter outlets, kill lines, sensors, vibration dampeners, transponders, ports for anti-freeze injection, ROV panels ... and stands 32 feet high and weights 78 tons.
On the bottom of the stack is a transition spool with a HC connector seal assembly designed to set down on the old Deepwater BOP via a riser assembly from the drill ship above, the first section of riser above the stack a perforated sub that will allow the well to blow into the sea while being capped.
This stack is built to handle 400 F liquids and work.
It did.
With a little nudging from ROV's the stack slid right in place slicker than a whistle, above. The well was capped July 13, 2010, 87 days after initial loss of surface control. The well was shut in and diverted in 3 stages in early August; flow to the Gulf of Mexico stopped. After one integrity test after another via transducers and ROV's circling the stack like bees, the well was eventually plugged with cement from the top, and eventually the bottom, once John Wright did his relief well intervention magic.
Not one human hand touched any of this capping procedure, it was all done with ROVs and engineering that to this day remains one of the greatest accomplishments in oilfield history.
Thanks, Sean; as always. The story on the water well was that the homeowner couldn't get a permit but he went ahead and tired to sneak it in anyway.
Damn right in honor of the men lost....
And a big nod to John Wright, king of the relief well. But who (or what) will replace him when he's done (like most of the old hand well control guys, pretty sure they are all 60 plus years old and then some by now). Hopefully the new generation will learn enough from the old. And as always, Thank You Professor.
P.S.- I'm sure the hands dealing with that water well blowout were glad it was just water, mud, and crap.