This morning’s operation was about as fun as my job gets. For an hour I maneuvered the ship one meter at a time so the driller could lower an 8-inch-diameter steel rod into a 19-inch hole, which was over a mile away.
The Remote-Operated Vehicle (ROV) pilot, the driller, and I all had a video picture of the seabed on our respective closed-circuit TV screens. This was being shot by the ROV’s camera, which the pilot kept aimed at the wellhead on the ocean floor. We were also in communication by way of a three-way telephone connection.
The ROV is a car-sized submarine that has propellers that are controlled by the pilot who sits in his control room on deck. He “flies” it on a tether that allows him to operate the robotic arms, cameras, lights, and even a smaller, auxiliary ROV stowed inside it. We call the small one Mini Me after the Austin Powers character because it looks like a scaled-down version of itself.
Our aim was to run the pipe down through the wellhead. After insertion, a built-in tool would remove the wellhead, the last remaining component of the well, from the seabed, and we’d pull it to the surface. The camper’s credo “Take only pictures, leave only footprints” applies to drill ships, except for the fact that we don’t even leave footprints since we are under rigid requirements to tread as lightly as possible.
Landing a flexible, mile-long pipe within a 19-inch hole is inherently difficult, and the ship’s motion wasn’t being particularly accommodating today. It had been blowing about 35 knots for a number of hours, which had kicked up a steep chop on top of a growing swell—probably a total of 15-18 feet. This gave the ship a rise and fall (heave) of about 3 feet. Doesn’t sound like much until you’re playing remote-control pin the tail on the oil well.
With the ROV standing by, the driller keeps the “stinger,” or the tip of the tool we’re running, about 3 feet above the level of the wellhead. Starting at about 30 feet away, I push buttons on my panel that move the ship slowly toward the wellhead. I know which way I need to go by looking at the TV screen that has the ROV’s heading on it. I can see both the wellhead and the stinger in the picture now, and the pilot maneuvers the vehicle to put them in line. When they’re aligned, I glance at the ROV’s heading and can see which way to move. Then it’s a matter of my pushing a few buttons to move the ship.
I enter the distance and bearing (in meters and degrees, respectively) of my desired position and watch the graphic display of the thrusters to make sure they’re obeying. The ship slowly moves toward the goal and stops when we get there. It will take several minutes for the bottom of the pipe to catch up. Picture trailing a piece of half-cooked spaghetti vertically through the water. It will bend, with the bottom end lagging behind the direction of travel.
Once I get the ship within 3 feet or so, the pipe slowly drifts around in lazy passes, sometimes passing inches from the aperture, sometimes feet away. Now it is almost pointless for me to try to help it because the ship’s motion, due to the waves and swell, keeps the pipe moving around anyway. I can’t move the ship fast enough to combat this, and random motion, in this case, is probably helping swing the stinger over the hole. If the pipe starts to trend away from the wellhead, I will enter a corrective move and maybe ballast the ship a bit to use the pipe’s pendulum effect to swing it in the desired direction. Ballast to port, the pipe will dangle to port. It’s an inexact science, but it is not one without its tricks.
After 30 minutes of incremental moves and adjustments, the telephone receiver is hot and stuck to my left ear, and the conversation is degrading. Three men who have been away from home for weeks can only try to guide a pipe into a hole for so long without the inevitable innuendo.
We concentrate, however, on the task. The stinger is swinging back and forth in line with the wellhead. It looks good, but the trouble with working remotely is that the TV picture is only two-dimensional. Although the pipe looks like it’s lined up, when the ROV swings around to look from 90 degrees around the pipe, we see that we’re still 3 feet out in the other axis.
One move solves that, and the pipe meanders toward the hole. I make sure the driller sees this, and as the pipe crosses over the opening, he eases off his brake. We penetrate, and I make sure the ship is stationary. We thank each other on the phone and hang up. Onward.
