ROVs shine in work on runaway Macondo well

Crews working on the runaway deepwater Macondo well use remotely operated vehicles to perform a wide-ranging multitude of tasks. About 12 ROVs are at the wellhead in 5,000 ft of water where no human diver can venture.

Although the overall oil spill response effort has been marred by disappointments, the ROVs and their operators score fairly high on successful operating performance and on safety since the Apr. 20 Deepwater Horizon drill rig accident.

Each ROV is controlled via a tether going up to a vessel on the Gulf of Mexico. Macondo is operated by BP PLC, whose executives say choreography ensures ROV tethers do not tangle with other equipment in the congested area.

In their most-publicized chore, ROVs provide the lights and cameras that enable the public to watch a live video feed of oil and gas spilling from the failed blowout preventer on Mississippi Canyon Block 252. Some ROVs ran the saws to cut off a portion of the riser while other ROVs kept up the live video feed for a public audience.

Most of the time, the ROVs work smoothly without attracting attention, although the undersea robots are believed responsible for one, possibly two, mishaps. During May, an ROV temporarily dislodged a riser insertion tube that collected leaking oil and gas. In June, an ROV might have bumped a containment cap, forcing BP to temporarily suspend some collection operations.

"There are an unbelievable amount of ROVs operating down there," National Incident Commander and retired US Coast Guard Admiral Thad Allen told reporters during a June 23 conference call. "I think the fact that we've had two bumps that have had some kind of a consequence associated with them in the 60-plus-days response is a pretty good record."