BP Riser Insertion Tube Reported Working, Some Oil and Gas from Deepwater Horizon Well Being Captured
|The riser insertion tube. Source: BP. Click to enlarge.|
The Unified Area Command for the response to the Deepwater Horizon oil spill reported on Sunday that the Riser Insertion Tube Tool—one of several subsea options BP is developing—was successfully tested and inserted into the leaking riser Saturday night, capturing some amounts of oil and gas. The oil was stored on board the Discoverer Enterprise drill ship 5,000 feet above on the water’s surface, and natural gas was burned through a flare system on board the ship.
The tool is fashioned from a 4-inch pipe and is inserted into the leaking riser (21-inch diameter pipe which contains the smaller drill pipe) between the well and the broken end of the riser, from which the majority of the flow is coming. Rubber diaphragms on the tool conform around the drill pipe to plug the riser as much as possible. While not collecting all of the oil flowing from the wreckage of the riser, successful deployment of this tool would be an important step in reducing the amount of oil being released into Gulf waters until the well can be capped.
|Situation status map as of 16 May (Sunday). Click to enlarge. Original pdf file here.|
The procedure—never attempted before at this depth—involves inserting a 5-foot length of the specifically-designed tool into the end of the existing, damaged riser from where the oil and gas is leaking. In a procedure approved by federal agencies and the Federal On Scene Coordinator, methanol will also be flowed into the riser to help prevent the formation of hydrates.
The insertion tube, in turn, is attached to its own 5,000-foot riser that conveys the hydrocarbons to the Transocean Discoverer Enterprise drillship on the surface. The Enterprise is capable of processing 15,000 barrels of oil per day and storing 139,000 barrels. A support barge will also be deployed with a capacity to store 137,000 barrels of oil.
The first attempt at insertion was unsuccessful. Following an adjustment on the surface, the tube was inserted on the second try. Testing was halted temporarily when the tube was dislodged. Technicians have fully inspected the system and have re-inserted the tool (the third attempt).
The Enterprise has the capability to separate the oil, gas and water mixture and eventually store or offload the recovered oil onto another vessel.
Interior Secretary Ken Salazar and Homeland Security Secretary Janet Napolitano issued a joint statement on the riser tube efforts:
Today, BP attempted another test to contain some of the oil leaking from the riser. This technique is not a solution to the problem, and it is not yet clear how successful it may be. We are closely monitoring BP’s test with the hope that it will contain some of the oil, but at the same time, federal scientists are continuing to provide oversight and expertise to BP as they move forward with other strategies to contain the spill and stop the flow of oil.
Relief well progress. The Development Driller III, drilling the first relief well, has finished running blowout preventer (BOP) stack and riser and is currently latching the BOP to the wellhead for the first relief well. The Development Driller II, which will drill the second relief well, is on location and is making preparations for initiating the drilling process and performing BOP maintenance.
Surface. NOAA earlier said that tarballs have been reported west of Galveston, Texas to the Florida panhandle. Testing already underway has shown some tarballs to be from the Deepwater Horizon spill and others not.
As of Sunday:
More than 650 vessels are responding on site, including skimmers, tugs, barges, and recovery vessels to assist in containment and cleanup efforts—in addition to dozens of aircraft, remotely operated vehicles, and multiple mobile offshore drilling units.
More than 1.25 million feet of containment boom and 440,000 feet of sorbent boom have been deployed to contain the spill—and approximately 285,000 feet of containment boom and 900,000 feet of sorbent boom are available.
Approximately 6.3 million gallons of an oil-water mix have been recovered.
Approximately 600,000 gallons of dispersant have been deployed. More than 280,000 gallons are available.
17 staging areas are in place and ready to attempt to protect sensitive shorelines, including: Dauphin Island, Ala.; Orange Beach, Ala.; Theodore, Ala.; Panama City, Fla.; Pensacola, Fla.; Port St. Joe, Fla.; St. Marks, Fla.; Amelia, La.; Cocodrie, La.; Grand Isle, La.; Shell Beach, La.; Slidell, La.; St. Mary, La.; Venice, La.; Biloxi, Miss.; Pascagoula, Miss.; and Pass Christian, Miss.
Sub-surface plumes. Earlier in the week (12 May), researchers from the National Institute for Undersea Science and Technology (NIUST) reported detecting substantial sub-surface plumes of oil.
Our preliminary working hypothesis is that this is hydrocarbon material that was produced by the well but that did not reach the surface, perhaps due to the deep injection of dispersants which BP has stated that they are conducting. We will continue to map these plumes with the techniques available to us but we suggest that a more thorough investigation of the composition and trajectories of this material is warranted.—NIUST