Bobbing like a CORK

It’s about 4500m to the seafloor where we’re working at Hole 395A. That’s about as deep as Mt. Rainier (in Washington State) is high, and almost 3 times as deep as the Grand Canyon! No wonder it takes so long to lower the drill string all the way to the bottom. But yesterday and today, we’ve been working on something that takes much longer—assembling the CORK

The team has been working hard to assemble the casing that will hang more than 500m below the seafloor. Each piece has to be assembled very carefully so that it runs smoothly down the borehole, and so that the equipment inside will survive and function for the next 5 years or more. There are more than 75 pieces that have to be assembled, from the very bottom of the casing (the bull nose) to the CORK wellhead that sits at the top in the re-entry cone on the seafloor.

CORK wellhead in the moon pool

These pieces, which include drill collars, fiberglass casings, steel tubes, and packers (special pieces that inflate to seal off different sections of the hole), all have to be lifted with a crane from wherever they’re stored on the ship to the drill floor, where the drillers use a variety of machinery and good old-fashioned elbow grease to put them all together. They work a lot more slowly with these intricate (and expensive!) pieces than they do with the drill string.

attaching a packer

When they attach each new piece, they lower the assembly down to the moon pool below, where another crew is waiting to attach a myriad of umbilical tubes that run along the outside of the casing. These tubes allow water to be pumped down into the packers to inflate them, and they allow water samples to be taken from valves on the wellhead by ROVs at a later time. The tubes all have to be carefully connected during the assembly so that when they are finally connected to the wellhead, each valve will do what it is intended to do. Imagine making a mistake and having to start all over again!

connecting the umbilical lines

We began this operation yesterday at about 2:00PM. People have been working nonstop all through the night and day, and into another night…it’s a very long process! And all the while, the JR is waiting patiently above the hole, bobbing like a cork.


You are playing our song: ROVS

I am imagining this in Lego and need some help. Can you tell me more about how -and what kind of - ROVS are used to take water samples from valves on the wellhead? I know ROVS are tethered underwater vehicles, so I assume the ROVs used are unmanned. How are they controlled? From a ship, by satellite / computer or by someone's phone while sitting at the McDonalds drive thru :)

How do the ROVS need to be constructed to retrieve that type of it like a robotic arm?


Julie and Luke

ROV video

hi julie & luke, here's a link to a video that describes the mission for a recent expedition that involved ROVs and CORKs: i hope it answers some of your questions!

rovs in recovery plan?

Thanks Jennifer, We are imagining an ROV with an amazing grappling tool to recover the cork :) julie and luke

Great minds!

I bet you and the scientists are on the same page.


well, if we are maybe we can talk about it when we skype in November ! this really unfortunate set back is inspiring me to issue a challenge to our club members: design an ROV model capable of retrieving what was lost! between SeaPerch/ ROV in a bag and Mindstorms NXT we should be able to imagine some sort of solution :) or at least learn along the way...