Deepwater Horizon

CCOM/JHC in the Gulf

The catastrophic events associated with the 2010 explosion of the Deepwater Horizon drill rig and the subsequent  three month spill from the Macondo 252 well. Staff from the Center (both NOAA and CCOM staff) responded quickly to the national call for help and continue to be active in Deepwater Horizon-related activities. In May 2010, the White House sponsored a meeting hosted by Presidential Science Adviser John Holdren that was attended by the Secretary of the Interior, the EPA Administrator, the Director of the USGS, and a number of top government officials to discuss, with representatives of the academic community, the role that they might play in addressing the many challenges posed by the Macondo spill.

Gas seeping from wellhead
Acoustic backscatter suggesting a small amount of gas is seeping from the wellhead.

Center Director Larry Mayer was invited to this meeting and suggested that acoustic techniques may be of some value in determining the fate of submerged oil and the background input of natural seeps. NOAA invited the Center to help plan and execute an acoustics program leading to the participation of Tom Weber, Larry Mayer, and NOAA Corps Officers (and Center students) Sam Greenaway and Glen Rice on cruises on board the NOAA Ships Gordon Gunter and Thomas Jefferson with the express purpose of mapping subsurface oil. Rice also spent several months assigned to the Subsurface Monitoring Group in Houma, MS, a group established to track vessels engaged in the monitoring of subsurface oil.

 

During the course of the summer, the team used scientific echo sounders (Simrad EK-60’s) to map the many natural methane gas seeps in the area, to directly observe oil in the upper ocean, and to examine some of the effects of the oil on marine organisms. A primary tool in this work was the use of the IVS3D Fledermaus mid-water mapping tool, the product of research at the Center and the result of a successful collaboration (though a Granite State Grant) with industrial associate IVS3D. Numerous adjustments were made in the mid-water software to optimize its use for the data collected in the Gulf.

In mid-July when the well was capped, the Center’s focus shifted from mapping subsurface oil to monitoring the integrity of the well and acoustically searching for gas escaping either from the wellhead or the nearby seabed (gas was considered to be the bellwether of something gone awry deep beneath the seabed). Both natural seeps and small leaks in the Macondo 252 and other wellheads were successfully mapped.


Environmental Response Management Application (ERMA)

An ‘acoustic curtain’ representing the backscatter from organisms in the Deep Scatter Layer.

Concurrently, Kurt Schwehr worked with the Environmental Response Management Application (ERMA) team in support of the Deepwater Horizon incident response seven days a week for several months. Schwehr joined the original ERMA engineering team of Rob Braswell and Michele Jacobi in 2007 and gained valuable first-hand experience through his participation in the 2010 Spill of National Significance (SONS) drill in Portland, ME in March 2010. Schwehr’s work with ERMA focused on vessel tracking using the maritime Automatic Identification System (AIS) received through the USCG National AIS network of receivers. In response to the Deepwater Horizon event, Schwehr reconfigured the ERMA feed to cover the Gulf of Mexico. In order to better highlight the response vessels, he used vessel-contracting lists from the USCG and BP. Identifying the vessels was difficult because the lists do not include the unique MMSI identification numbers. Schwehr has used both NAIS ship name reports, outside databases (e.g., ITU registrations), and brute-force visual searching of vessel movements to create a master list of response vessels with the required MMSI. This list is now in ERMA and allows the system to present the response vessels separate from the rest of the local AIS traffic.

This is especially important in the very busy Gulf of Mexico environment. Schwehr also completely rewrote his AIS decoding and database updating software to meet the heavy load of presenting all the vessel traffic in real time for such a large and busy water way. The USCG has designated the CCOM/JHC ERMA NAIS feed as a “Critical Client.” On June 14, 2010, NOAA released ERMA to the public and, by a decree of Admiral Thad Allen, the responder vessel positions from NAIS were released in near real-time (every two minutes). This was a first for the NAIS system, which is usually used behind the scenes by government staff. The public GeoPlatform site is available at http://gomex.erma.noaa.gov/erma.html and the protected responder site is https://gomex2.erma.unh.edu/ (account required).

Seeps on the edge of a salt dome
Seeps mapped on the edge of a salt dome a few miles from the wellhead.

The GeoPlatform system uses the ERMA databases, map layers, and visualizations on the NOAA WOC server farm to provide a public Gulf Response. As a result of the success of ERMA and GeoPlatform, the team won a Government Computer News award. Both support at sea and on shore (data processing, cruise planning, data visualization) were provided during the Deepwater Horizon response; seagoing support was provided until mid September and lab-based support is still on-going. Weber participated in four cruises (two as chief scientist) aboard the NOAA Ships Gordon Gunter and Pisces. During the single cruise on the NOAA Ship Thomas Jefferson that gained close (1500 m) access to the wellhead during the spill, Weber provided round-the-clock, on-shore analysis of the data being collected. During this time, Mayer was providing daily four-dimensional (space and time) data visualization products for the Unified Command’s Subsurface Oil Unit. Over the course of the wellhead integrity monitoring mission (several weeks from mid July to early August), Weber was responsible for examining all acoustic data collected by the NOAA Ships Pisces and Henry Bigelow (this includes cruises for which Weber did not participate: data were uploaded in near real time). During this phase, Mayer reported daily (often several times per day) to the Secretary of Energy and his Science Review Team.

After the well was capped, Weber was chief scientist for a cruise that mapped the signature of the oil more than 400 km west of the wellhead. Weber also represented the acoustic mapping team at the June 2010 oil spill workshop in Miami, and participated heavily in cruise planning and execution throughout the summer. Both Weber and Mayer are the only two academics that are officially part of the Unified Command’s Joint Analysis Group (JAG).


In the Aftermath

As a continuation of efforts related to Deepwater Horizon, a data analysis was conducted in order to develop and test a methodology for estimating the oil concentration and flow rate based on high frequency acoustic measurements. Although the uncertainty in the result is high due to lack of absolute knowledge of the properties of the oil droplets (e.g., their size distribution), the flow rate estimate is remarkably consistent with those made at the wellhead by other means. The results of this analysis demonstrate a methodology for acoustically assessing oil in the water column that can be used to help quantitatively assess the fate of spilled oil for future incidents. One of the highlights of this project is the collaborative effort between the Center, NOAA NMFS, and NOAA OCS, all of whom played important roles in the DWH response and in this subsequent analysis. Should the need to respond to a similar response arise, this NOAA/Academic team will be well poised to contribute with specific (and documented) methodologies. A manuscript describing these efforts has been published in the Proceedings of the National Academy of Science.

Perturbations in the acoustic backscatter
Perturbations in the acoustic backscatter from marine organisms mapped a few km from the wellhead.

Immediately following the Deepwater Horizon explosion and leak of the Macondo well head, we proposed the use of a 30 kHz multibeam sonar with water column capability (Kongsberg Maritime EM302) as a potential tool for mapping deep oil and gas spills and monitoring the well head for leaks. At the time of the spill, such a system was not available (the Okeanos Explorer equipped with an EM302 was deployed in Indonesia) so instead we used 18 and 38kHz fisheries sonars. These sonars proved very effective at identifying gas seeps and leaks but have limited areal coverage and limited spatial resolution as compared with the multibeam sonar. In August and September of 2011, we finally had the opportunity to bring the EM302 multibeam echo sounder onboard the NOAA Ship Okeanos Explorer to the Gulf of Mexico in order to test the EM302 water column mapping capability for detecting and characterizing methane gas seeps, including comparison against data collected with a Simrad 18 kHz EK60 split-beam echo sounder (a known performer for finding seeps in the Gulf of Mexico) which was purchased and installed on the Okeanos Explorer for this cruise. During this relatively short cruise (less than two weeks of active mapping), a Center team led by Tom Weber and including Jonathan Beaudoin, Glen Rice, Kevin Jerram and Maddie Schroth-Miller mapped 17,477 km2 of the northern Gulf of Mexico making 573 seep observations (some of which were repeat observations of the same seep). Working in 1200-2500 m water depth, Weber developed seep detection algorithms while Beaudoin developed software that allowed the precise geolocation of the targets for presentation in a 3D context. We found that we were able to most reliably detect seeps over a swath that was approximately twice the water depth. At farther ranges, reverberation from the seafloor tended to dominate the return from the seep, significantly reducing the likelihood of detection. The results from this cruise demonstrate a new midwater mapping technology for the Okeanos Explorer, and also suggest that widescale mapping of seeps in the deep Gulf of Mexico—an objective that is important for both scientific and industry management perspectives—is viable. This cruise also resulted in a NOAA press release, http://www.noaanews.noaa.gov/stories2011/20110915_okeanosexplorer.html.


Related Media Coverage

Multibeam Sonar to Detect and Map Deep-sea Gaseous Seeps - Hydro International, Sept. 16, 2011

UNH Developers Share Honors for Oil Spill Response Tool - UNH Campus Journal, May 11, 2011

UNH Oceanographer to Lead National Oil Spill Committee - Seacoastonline.com, Feb. 5, 2011

Listening for Oil Spills - Science Now, Nov. 16, 2010

Analysis: Did Gulf Dodge an Ecological Bullet? - Reuters, Aug. 5, 2010

Oil below the surface: UNH ocean mapping center tracks Gulf spill underwater  - Seacoast Online, Jul. 11, 2010

The Deepwater Horizon Response Mission Report - Jun. 30, 2010

What are 'phantom' oil plumes? - CNN.com, Jun. 28, 2010

Gulf oil dispersants 'lesser of two evils' - NECN, Jun. 9, 2010

NOAA ship to search for underwater oil plumes from leak site - The Washington Post, Jun. 3, 2010

NOAA research ship to search Gulf for underwater oil  - mcclatchydc.com, Jun. 1, 2010