Friday, August 20, 2010

Day 121 BP Oil Spill: Maybe A "Kill" Labor Day Week; 22-Mile Plume

Aug 20: At the August 19, press briefing, Thad Allen, National Incident Commander explained that over the last week or so that intense negotiations and discussions between the government science, team headed by Energy Secretary Steven Chu and the BP engineers in Houston have taken place regarding the so-called "bottom kill" operation to intercept the well bore with a relief well and permanently close the well with mud and cement.
    Allen explained that the central point of discussion has revolved around the likelihood of pressure building in the annulus between the well and well bore at the time of intersection. The consultations thus far revolved around two potential scenarios. One involves going ahead and intersecting the annulus with the current blow out preventer and the capping stack in place. The other one is to replace the current blow out preventer and capping stack with a new blow out preventer prior to conducting the intersect. 
    He said that as those discussions were taking place, BP was directed to prepare the blow out preventer on Development Driller II -- the one that's associated with the second relief well -- for use as a blow out preventer, should it be needed. BP was also directed to flush out the current blow out preventer and capping stack, clean it out and fill it with sea water in anticipation of an ambient test with sea water in the BOP that is the same liquid that we have outside the BOP to allow us to do a more accurate pressure test. He said those operations have been completed and late August 18, the decision was made to proceed to remove the current blow out preventer and capping stack, replace it with a new blow preventer in advance of the well kill subject to conditions.
    Allen said the ambient pressure testing would take approximately 48 hours (i.e. ending August 21) and if there are no anomalies and no hydrocarbons present, then they would conduct what is being called a "fishing experiment." He said, "We are going to actually put a drill bit down in the blow out preventer and attempt to extract the drill pipe. The reason we want to try and extract the drill pipe that reduces the risk that when we remove the blow out preventer and put the new one on, there won't be an (off score) or some kind of a bar to having a seal with the new blow out preventer. And we have told BP you need to do the ambient test, conduct the fishing experiment, come back to us with the results and then we will proceed after that. . ."

    Allen said all of the operations have been done with an "overabundance of caution related to minimizing risk associated with the intersection of the well." He said, "We are very, very close to the end. This gets to be a very, very complex evolution and there are no black and white choices here and this has required a significant amount of discussion. . . At the press brief yesterday someone asked about a timeline, I said there was no timeline at the present and that was true.  There remains a sequence of events that will be carried out. They are conditions based. When we take one step and we are successful, we will move to the next step. Should all these steps prove successful and we move towards the eventual intersection of the well, that could take place sometime the week after Labor Day.
Researchers Find "Conclusively" A 22-Mile Gulf Oil Plume 
Aug 19: Scientists at the Woods Hole Oceanographic Institution (WHOI) have detected a plume of hydrocarbons that is at least 22 miles long and more than 3,000 feet below the surface of the Gulf of Mexico, a residue of the BP Deepwater Horizon oil spill. The 1.2-mile-wide, 650-foot-high plume of trapped hydrocarbons provides at least a partial answer to recent questions asking where all the oil has gone as surface slicks shrink and disappear [See WIMS 8/17/10]. Christopher Reddy, a WHOI marine geochemist and oil spill expert and one of the authors of the study, which appears in the August 19 issue of the journal Science said, "These results indicate that efforts to book keep where the oil went must now include this plume" in the Gulf. 

    The researchers measured distinguishing petroleum hydrocarbons in the plume and, using them as an investigative tool, determined that the source of the plume could not have been natural oil seeps but had to have come from the blown out well. Moreover, they reported that deep-sea microbes were degrading the plume relatively slowly, and that it was possible that the plume had and will persist for some time.

    The WHOI team based its findings on some 57,000 discrete chemical analyses measured in real time during a June 19-28 scientific cruise aboard the R/V Endeavor, which is owned by the National Science Foundation (NSF) and operated by the University of Rhode Island. They accomplished their feat using two highly advanced technologies: the autonomous underwater vehicle (AUV) Sentry and a type of underwater mass spectrometer known as TETHYS (Tethered Yearlong Spectrometer). Richard Camilli of WHOI's Applied Ocean Physics and Engineering Department, chief scientist of the cruise and lead author of the paper said, "We've shown conclusively not only that a plume exists, but also defined its origin and near-field structure. Until now, these have been treated as a theoretical matter in the literature."
    Camilli said, the plume has shown that the oil already "is persisting for longer periods than we would have expected. Many people speculated that subsurface oil droplets were being easily biodegraded. Well, we didn't find that. We found it was still there." Reddy said, "Whether the plume's existence poses a significant threat to the Gulf is not yet clear, the researchers say. We don't know how toxic it is and we don't know how it formed, or why. But knowing the size, shape, depth, and heading of this plume will be vital for answering many of these questions."
    Access the transcript of the August 19 press briefing with Q&As (click here). Access more information on BP activities from the BP response website (click here). Access the Restore the Gulf website for more information (click here). [*Energy/OilSpill]
Access a lengthy release on the WHOI research with pictures, graphics and video (click here).