Leaking Well at Platform 23051 Location – Rate?

Just a quick followup to our last post. The Ocean Saratoga rig is working to plug 26 wells that had been connected to an oil platform damaged (and destroyed, or removed) by Hurricane Ivan in 2004:

The Taylor wells are leaking an average of less than one- third of a barrel of oil each day, the Interior Department said. The leaks have been “substantially reduced” over the years by containment domes and other interventions, Taylor said in a statement yesterday.

1/3 of a barrel is 14 gallons. The slick we measured on June 18 satellite imagery holds an estimated 3,157 gallons of oil, assuming the slick is only 1 micron thick. It would take 225 days, at a rate of 14 gallons per day, to make an oil slick that large. Oil on the surface of the ocean can’t survive that long — especially a slick that’s only 1/1000th of a millimeter thick.

The leakage rate from these wells in recent days must be significantly higher, probably in the range of 100-400 gallons per day. If they’ve been leaking at that rate since Hurricane Ivan, that’s a total of 210,000-840,000 gallons of oil. To put it in perspective, less than one day’s worth of leakage from BP’s Macondo well.

BP / Gulf Oil Spill – June 12 MODIS/Aqua Image

This MODIS/Aqua satellite image, taken on June 12, has a broad sunglint pattern centered on the eastern Gulf that effectively illuminates the main oil slick as well as areas of what we interpret as much thinner sheen. The bright band of sunglint spanning this image reveals fine structure (squiggly bright lines) in areas to the east of what we interpret as the main area of oil slick; this structure can be caused by natural surfactants, or it may indicate very thin layers of residual sheen related to the ongoing spill. As on June 9, there is some ambiguity in our delineation of the area of slicks and sheen (orange line), which extends across an area of 23,140 square miles (59,932 km2) — as big as our home state of West Virginia:

MODIS/Aqua satellite image taken June 12, 2010

Oil appears to be making landfall across 40 miles of coast east of Mobile Bay, from Gulf Shores, Alabama to Perdido Key, Florida. Tendrils of oil, possibly thin sheen, reach toward the Florida coast from Pensacola almost as far east as Panama City. Some news accounts support this analysis.

And the government just revised the estimated leak rate from the well – they now say it’s leaking anywhere between 1.5-2.5 million gallons per day, with the containment device currently capturing about 500-600 thousand gallons of that flow. That means that since BP cut the riser and installed the latest containment cap, at least 900 thousand gallons – and possibly as much as 2 million gallons – have entered the Gulf daily. At the high end that’s nearly twice as much as the 1.1 million gallon estimate SkyTruth and Dr. Ian MacDonald of Florida State University made back on May 1.

BP / Gulf Oil Spill – Memo Shows BP’s Spill Rate Calculations

Dr. Ian MacDonald at Florida State University just provided us with this BP memo detailing the spill-rate calculations performed by BP. Click it to see the full-sized version. We guess this is how BP came up with their very low estimated leak rates of 42,000 gallons (1,000 barrels) and 210,000 gallons (5,000 barrels) per day. The official estimated leak rate now stands at 20,000-30,000 barrels per day (and possibly much higher).

Read more about the varying spill-rate estimates, and this memo, in a Washington Post article by Joel Achenbach.

BP / Gulf Oil Spill – June 7 and June 9, 2010

Playing some catch-up from Capital Hill Ocean Week. We served on a panel yesterday and gave a presentation on the spill (starting at 36:10 in this video). Thanks for your patience, we’re stretched pretty thin!

Here are MODIS/Terra satellite images of the Gulf from June 7 and June 9. The image taken June 7 shows slick and sheen across an area of 9,075 square miles (23,504 km 2). A large dark area west of the slick may be a low-wind area within the generally bright belt of sunglint west of the Mississippi Delta. There may be slicks or sheen obscured by this low-wind region:

MODIS/Terra satellite image taken June 7, 2010

Compare this with the MODIS/Terra taken on June 9, which has a broad sunglint pattern centered on the eastern Gulf that effectively illuminates the main oil slick as well as areas of what we interpret as much thinner sheen. The bright band of sunglint spanning this image reveals fine structure (squiggly bright lines) in areas to the north, south and west of what we interpret as the main area of oil slick; this structure can be caused by natural surfactants, or it may indicate very thin layers of residual sheen related to the ongoing spill. Lots of judgment calls made when encircling the area of slicks and sheen (orange line), but we come up with a total area of 16,434 square miles (42,565 km2):

MODIS/Terra satellite image taken June 9, 2010

We don’t think the actual area of ocean affected by slicks and sheen nearly doubled in just two days; instead, we think the MODIS image from June 9 was just much more effective at showing those areas than many of the images we’ve been collecting throughout this incident. And it is possible that some of the area we’ve delineated contains natural surfactant rather than spilled oil. Again, a difficult image to interpret in some areas.

Platform 23051 vs. Ocean Saratoga Rig – Not The Same Thing?

UPDATE 6/11/10 4pm – We’re wondering if Platform 23051 was destroyed by Hurricane Ivan in 2004, and if the Ocean Saratoga rig is actually working at the site of the destroyed platform. This would make a lot of sense. If anyone has information that would confirm (or refute) this, please let us know.

UPDATE 6/11/10 5pm – John Wathen tells me that the pilot collected a GPS location while they flew over the Ocean Saratoga rig last weekend. John gave me the GPS coordinate, and it plots right on top of the MMS-given location coordinate for Platform 23051. So I think the platform was destroyed by Ivan, and the leaking well that the Saratoga is working to plug is the well that was under Platform 23051.

Conclusion: the persistent slicks we’ve been seeing on multiple satellite images are apparently caused by the continuing leakage from this hurricane-damaged well. It would be great if someone from MMS or the Coast Guard would confirm this.

Some recent media reports about our work related to possible leaks unrelated to the BP spill have gotten a few things wrong. Here’s a clarification: based on our analysis of multiple satellite images collected since April 25, we see what appears to be a small but persistent oil slick at or very near the known location of Platform 23051. According to MMS this is a fixed oil platform, installed in the 1980s, that has a crew onboard. If this is indeed a small oil slick, it might indicate a small chronic leak related to that facility; it might also be coming from a natural oil seep on the seafloor at or near the platform. There may be other causes that we are not aware of.

Based on the location we published for that platform (a location obtained from the MMS platforms database), a professional photographer flew over the general vicinity and documented what appeared to be an oil slick next to a semisubmersible drill rig. A company news release explains that this rig, the Ocean Saratoga, is working to plug a well that was damaged by Hurricane Ivan back in 2004. The well was reportedly covered by a seafloor landslide, so this is a difficult operation.

None of this changes our main question: how common are smaller spills like this, whatever their cause? What are the impacts? Is this a problem in the Gulf, or not? Would it be a problem with drilling elsewhere, such as in the Arctic or off the coast of Florida?