According to a release, based on three separate methodologies, outlined below, the independent analysis of the FRTG has determined that the overall best initial estimate for the lower and upper boundaries of flow rates of oil is in the range of 12,000 and 19,000 barrels per day. The FRTG used three separate methodologies to calculate their initial estimate, which they deemed the most scientifically-sound approach, because measurement of the flow of oil is extremely challenging, given the environment, unique nature of the flow, limited visibility, and lack of human access to BP's leaking oil well.
While the estimate is far more than the previous estimate of 5,000 barrels per day, it is still far short of what other experts have estimated. On May 19, at a hearing held by the House Energy & Commerce Committee, Environment and Energy Subcommittee, Chaired by Representative Ed Markey (D-MA), Steve Wereley from Purdue University said he was confident that the rate is an "order of magnitude" higher than the BP estimate (i.e. the previous 5,000 bbl/d estimate). He testified that he could see no scenario where the BP estimate is accurate. He said his current estimate is in the range of 70,000 to 120,000 barrels per day [See WIMS 5/20/10].
The three methodologies used by the FRTG included a Mass Balance, Plume Modeling and a Riser Insertion Tube Tool (RITT) estimate approach. The Mass Balance Team analyzed how much oil is on the surface of the Gulf of Mexico and estimated a spill rate in the range of 12,000 to 19,000 barrels of oil per day. The Plume Modeling Team used video observations of the oil/gas mixture escaping from the kinks in the riser and at the end of the riser pipe alongside advanced image analysis to estimate fluid velocity and flow volume. Based on advanced image analysis and video observations the Team estimated a range of 12,000 to 25,000 barrels of oil per day.
The final estimate was calculated based on the amount of oil collected by the RITT, plus the estimate of how much oil is escaping the RITT, and how much oil is leaking from the kink in the riser. At one point, the RITT logged oil collection at a rate of 8,000 barrels of oil per day, as measured by a meter whose calibration was verified by a third-party. The team estimated that at least 10% of the flow was not being captured by the riser at the time oil collection was logged, increasing the estimate of total flow to 8,800 barrels of oil per day. Factoring in the flow from the kink in the riser, the RITTI Team calculated that the lower bound estimate of the total oil flow is at least 11,000 barrels of oil per day, depending on whether the flow through the kink is primarily gas or oil.
The release indicates that the preliminary estimates provided by the FRTG are based on new methodologies being employed to understand a highly dynamic and complex situation. "As the FRTG collects more data and improves their scientific modeling in the coming days and weeks ahead, they will continue to refine and update their range of oil flow rate estimates, as appropriate. The FRTG is working diligently to ensure all estimates are peer reviewed by independent experts and academics as expeditiously as possible. They will also establish a website to ensure this information is available and reported to the public in a timely fashion."
In the meantime BP reported that the "top kill" operation continued over the night and are ongoing. Although there were rumors of positive results throughout the day, BP said, "There are no significant events to report at this time" and indicated they will provide updates on progress as appropriate. The President held a press conference and announced 6 month moratorium on deepwater drilling and new safety measures for offshore oil and gas drilling. Further details are being release later today.
Access a release on the latest results of the FRTG with additional details (click here). Access the President's remarks at the press conference (click here). Access the Unified Command website for complete updates (click here). Access the BP response website for complete details on their response efforts (click here). Access the White House website on the BP spill which contains links to all Federal agency response websites (click here).