BP / Gulf Oil Spill – Stopped (For Good?)

Screen capture from Skandi ROV2 live spill cam, 12:42am EDT, July 16, 2010

Finally, after 87 days, the leak from BP’s Macondo well in the Gulf of Mexico is fully stopped. All the valves on the new sealing cap have been closed and an “integrity test” is being conducted on the well. If the pressure steadily increases in the well, that’s a good thing: it would mean there are no leaks in the wellpipe and casing below the seafloor. In that case BP will keep the valves closed, effectively shutting off this catastrophic spill. If the pressure doesn’t build in the well it could mean there are leaks below the seafloor, and BP will re-open some of the valves and the spill will resume. In any event, the only permanent solution is a successful relief well that fills the damaged well with cement.

MODIS / Aqua satellite image, July 14, 2010

This MODIS / Aqua satellite image, taken on July 14, shows that the area of oil slicks and sheen appears greatly reduced: slicks cover approximately 3,786 square miles (9,805 km2) on this image. Radar satellite images taken on July 11 and July 12 confirm this smaller slick area.

Persistent, moderately strong winds over the past few days (ranging from 7-20 miles per hour) may have dispersed thinner portions of the slick over much of the region.

BP / Gulf Oil Spill – Radar Comes Through Again

This satellite radar image taken by Envisat’s ASAR sensor at 10:44pm local time on July 7 shows a large patch of oil extending north from the site of the leaking Macondo well, and an area of small slicks along the Mississippi shoreline:

Envisat ASAR radar image (black-and-white) taken July 7, 2010. Image courtesy of CSTARS.

A large dark area extending from west of Mobile Bay to beyond Panama City may include patchy oil slicks and sheen, as seen in this area on previous days. But it is also an area of calm winds; the surface wind speed was measured at Buoy 42012 at 1 meter per second, gusting to 2 m/s, at the time this image was acquired. That’s on the low-end threshold for oil slick detection with radar imagery.

This infrared GOES weather satellite image taken within minutes of the radar image shows the skies are mostly clear in the area, with no sign of rainfall:

BP / Gulf Oil Spill – July 4th Weekend

With oil continuing to billow into the Gulf of Mexico from BP’s failed Macondo well, the holiday weekend brought little cause for celebration, and no break for the folks working hard to clean up the oil coming ashore and to plug the leaking well. Oil was reported for the first time in Lake Pontchartrain, and the discovery of tar balls on some Texas beaches means this spill is now directly impacting all of the Gulf states.

A RADARSAT-2 satellite image taken July 2 shows oil slick and sheen still spread across a large area of the Gulf in the wake of Hurricane Alex, which brought large waves and strong gusty winds to the area last week:

RADARSAT-2 satellite image taken July 2, 2010. Image courtesy of CSTARS.

MODIS satellite images acquired on July 3 and July 4, while impaired once again by clouds, showed portions of the oil slick in a few areas. The July 3 image shows patches of slick along the Louisiana coast reaching west beyond Vermilion Bay:

MODIS/Aqua satellite image acquired on July 3


It also shows a neat little circular pattern formed by a cluster of natural oil and gas seeps; the small slicks that form at the ocean surface above these deepwater seeps appear to be caught up in a clockwise gyre (a rotating surface current).See all the images in our Deepwater Horizon Oil Spill gallery.

BP / Gulf Spill – NOAA Forecasts Long-Term Threat To Coasts

NOAA has just released the results of modeling to analyze the long term threat posed by the ongoing oil spill to coastlines throughout the Gulf, Florida Keys, and East coast shorelines:

NOAA forecast showing likelihood of coastline being threatened by oil over the long term by BP spill

Their model shows the probability that oil will approach within 20 miles of the shoreline. It assumes the net daily spill rate is 1.4 million gallons (33,000 barrels) per day for 90 days beginning April 22, when the Deepwater Horizon rig sank and the fire was extinguished. We’re at Day 76 right now, so this assumes a relief well plugs the leak within the next 2 weeks. They are steadily closing in on the target depth of about 13,000′ below the seafloor, so we’re hopeful BP will succeed ahead of their stated mid-August goal.

The model is based on historical wind and ocean current information, and accounts for the natural breakdown of oil at sea. It doesn’t account for the movement and ultimate fate of oil beneath the water’s surface, because we just don’t know enough about that yet. Read all about the model and the assumptions and data used to run it. You can also see other maps, graphics, animations and movies showing the model results for individual scenarios.

Platform 23051 / Ocean Saratoga Site Revisited

June 5, 2010: Oil slick next to Ocean Saratoga semisubmersible drill rig. Rig is working to plug leaking wells that were damaged by Hurricane Ivan in 2004. Photo courtesy J. Henry Fair.

 

June 25, 2010: Oil sheen marked by orange buoy. Rig was not observed in the area. Photo courtesy J. Henry Fair.

A few weeks ago we noticed a small but persistent slick on satellite images, appearing near a known oil platform location, designated Platform 23051 in a government database of all Gulf oil and gas platforms (including platforms that have been destroyed or removed). J. Henry Fair, a professional photographer, was flying over the site a few days later and captured photos and video showing an oil slick next to a semisubmersible drilling rig called the Ocean Saratoga. We learned the rig was not the source of any leak – it was working to plug one of 26 leaking oil wells that had been damaged by Hurricane Ivan in 2004, and have apparently been leaking ever since. Platform 23051 must have been destroyed during Ivan, or so badly damaged that it was subsequently removed.

The Coast Guard reported the wells were leaking, on average, just 14 gallons per day; and a containment device was said to be capturing most of that oil. But based on the size of the oil slick, we calculated a leakage rate in the range of 100-400 gallons per day. In our most recent observation on satellite imagery, June 18, the oil slick is 12 miles long and covers 4.5 square miles. The Ocean Saratoga is apparent as a bright dot on the radar image near the western end of the slick.

Mr. Fair flew over the site again on June 25 and took photographs showing a thin oil slick (rainbow sheen) marked by an orange buoy at one end, with no sign of the Ocean Saratoga rig or any other activity. It’s possible the rig was towed back to shore to ride out tropical storm Alex, or has been moved to another job. As long as we keep getting satellite imagery covering the nearby BP oil spill, we should have more opportunities to check up on the progress at stopping this small but persistent leak.