Appendix A

Peer Review Charge Document

The National Academy of Sciences has been contracted to conduct a peer review of OSRR 1063: Bureau of Safety and Environmental Enforcement Report: Computational Fluid Dynamics Model for Predicting Wellhead Oil-Burning Efficiency at Bench and Intermediate Scales: Interim Report (July 30, 2020) produced by the U.S. Naval Research Laboratory (NRL) and funded by the Bureau of Safety and Environmental Enforcement (BSEE). The work will be overseen by the Board on Chemical Sciences and Technology (BCST) in the Division on Earth and Life Studies. The peer review will focus on the methods, data quality, and strengths of any inferences made by the NRL study and as such, the final peer review report will focus on the technical nature of the interim final report (OSRR 1063).

CONTEXT

The Bureau of Safety and Environmental Enforcement (BSEE), within the U.S. Department of the Interior, is responsible for permitting, oversight, and enforcement of the laws and regulations governing offshore oil and gas development. Within BSEE, the Oil Spill Preparedness Division (OSPD) is responsible for developing and administering regulations specifically related to the oil and gas industry’s preparedness to contain, recover, and remove oil discharges from facilities operating seaward of the coastline. As part of its permitting authority, BSEE must certify that operators are prepared to respond in the event of a loss of well control and a “worst-case” release.

BSEE’s OSPD is currently reviewing a proposal by an independent operator to use wellhead burning to mitigate the effects of a potential well blowout from a gravel island in federal waters off the north slope of Alaska. Because BSEE is charged with ensuring that offshore oil and gas development occurs with minimal environmental impact, it is critical that permitting, oversight, and regulatory decisions are based on the best available science. Therefore, as part of the review process of the independent operator’s proposal, BSEE contracted with the U.S. Naval Research Laboratory (NRL) to conduct a literature review and provide preliminary technical guidance on the feasibility of wellhead burning as a mitigation method. Based on the literature review, it was determined that there is not sufficient evidence in the published literature to support the proposal that wellhead burning would be efficient enough to minimize unburned oil fallout. BSEE then contracted with NRL to conduct a full research program, with the primary objective of developing a computational fluid dynamics (CFD) model with experimental validation at multiple scales (bench-scale to intermediate-scale). BSEE is seeking an independent peer review of the interim final NRL report of the CFD and experimental validation results.

As part of its work, NRL developed a repeatable, reliable method to measure burn efficiency. The results of NRL’s scientific research are anticipated to be highly influential in the field. Because of this, it is important that the interim final report undergo a thorough, independent peer review to ensure that the methods, data quality, and strengths of any inferences made are based on the best available science.

The primary purpose of this peer review is to assist BSEE in effectively assessing spill mitigation strategies as part of its role in permitting offshore oil and gas development. As such, BSEE will be the primary audience for the peer review report. The peer review report may also be of interest to academic, industry, and government researchers in related fields (e.g., petroleum engineering; chemical engineering; computational fluid dynamics modeling; transport phenomena; combustion science) and private sector companies with interest in Arctic oil and gas development.

PEER REVIEW COMPONENTS

An ad hoc National Academies Committee will provide a peer review of OSRR 1063: Bureau of Safety and Environmental Enforcement Report: Computational Fluid Dynamics Model for Predicting Wellhead Oil-Burning Efficiency at Bench and Intermediate Scales: Interim Report (July 30, 2020) produced by the U.S. Naval Research Laboratory (NRL) and funded by the Bureau of Safety and Environmental Enforcement (BSEE). Specifically, the committee will write a report that addresses:

• The technical quality and completeness of the interim final report;
• The assumptions and approach used to develop the computational fluid dynamics (CFD) model; and
• The completeness of the modeling results and experimental validation as an evidence base for determining whether wellhead burning is sufficient for mitigation of uncontrolled environmental release of oil in the event of loss of well control.

As part of the peer review, committee members will respond to the following evaluation criteria:

1. Were the objectives of the study clearly defined? If not, what are your recommendations for improving the description of this study’s objectives?
2. Were the assumptions regarding wellhead conditions and two-phase wellbore flow (including film thickness and instability, liquid entrainment, and droplet diameter and its influence on wellhead ejection behavior) adequately characterized? Were there any apparent strengths, weaknesses, omissions, or errors? Provide an explanation for your answers.
3. Was the physical model for multi-phase flow adequately developed to capture the liquid droplet phase and the gas-phase flow field? Were the soot and radiation models adequately characterized? Were Lagrangian droplet dynamics and thermophysics adequately incorporated into the model? Were there any apparent strengths, weaknesses, omissions, or errors? Provide and explanation for your answers.
4. Does the droplet injection model adequately simulate realistic diameters and velocities of two-phase, high-speed flows that would occur during a wellhead blowout event? Were there any apparent strengths, weaknesses, omissions, or errors? Provide an explanation for your answers.
5. Does the validation process capture the controlling physical properties to a sufficient level of accuracy including transport and boundary conditions at the bench- and intermediate-scales for both gas-phase and two-phase turbulent spray? Were there any apparent strengths, weaknesses, omissions, or errors? Provide an explanation for your answers.
6. Were the phase doppler anemometry and diffuse back-light illumination imaging diagnostic methods (6.1.1 and 6.1.2 below) for the droplet behavior measurements appropriately designed, clearly described, and adequate to capture droplet behavior for the Gas Phase and Two-Phase Spray Flame? Were there any apparent strengths, weaknesses, omissions, or errors? Provide and explanation for your answers.

   6.1.1.1. Phase Doppler Anemometry

   6.1.1.2. Diffuse Back-Illumination Imaging

7. Were the diagnostic methods (7.1.1 and 7.1.2 below) for the temperature measurements appropriately designed, clearly described, and adequate to capture temperature for the Gas Phase and Two-Phase Spray Flame? Were there any apparent strengths, weaknesses, omissions, or errors? Provide an explanation for your answers.

   7.1.1.1. Coherent Anti-Stokes Raman Spectrometry-based Thermometry (CARS)

   7.1.1.2. 3-Color High-Speed Pyrometry

8. Do the results adequately characterize evidence of the droplet characteristics including droplet breakup, the droplet size (diameter), droplet speed, and the duration of droplet in fire (bench- and intermediate-scales)? Does the research product accurately expand predictions of droplet

diameters beyond current limited validated ranges? Were there any apparent strengths, weaknesses, omissions, or errors? Provide an explanation for your answers.

9. Does the research product accurately characterize the impact of two-phase flow regimes (bubble, slug, and churn) on the effluent plume (bench- and intermediate-scales)? Were there any apparent strengths, weaknesses, omissions, or errors? Provide an explanation for your answers.
10. Does the research product adequately address how the wellbore flow would influence the ejected spray plume behavior, which directly influences how the oil and gas burns and how much will either fall back to the surface or remain vapor? Were there any apparent strengths, weaknesses, omissions, or errors? Explain for your answers.
11. Does the research product accurately predict the length of fire plume, location of flame anchoring, height of flame, width/angle, expansion, etc.? Were there any apparent strengths, weaknesses, omissions, or errors? Explain for your answers.
12. Does the research product determine the primary mechanism driving burn efficiency?
13. Were the conclusions based on the OSRR 1063 study findings in the report logical and appropriate based on the results? What other conclusions related to the study were made and are appropriate? Are there any additional study findings or conclusions that could be drawn from the study? Provide an explanation for your answers.

REVIEW PROCESS

All peer review committee members will receive a PDF copy of the NRL report OSRR 1063: Bureau of Safety and Environmental Enforcement Report: Computational Fluid Dynamics Model for Predicting Wellhead Oil-Burning Efficiency at Bench and Intermediate Scales: Interim Report (July 30, 2020). All review comments will be entered via a web-based interface: [https://survey.alchemer.com/s3/6218414/BSEE-Wellhead-Report-Charge-Question]. Comments should be entered no later than April 12, 2021.

Please remember that all review comments remain confidential until the final National Academies review report is published. Review comments, without attribution, will be published as an appendix (See Appendix B of this report) to the review report. All closed session discussions and deliberations will remain confidential even after the review report is published. All draft report materials are confidential work products of the committee. Only when the review report is publically released can you discuss the report contents (but never the deliberations).

All peer reviewers should be aware of “applicable access, objectivity, reproducibility and other quality standards under federal laws governing access and quality. More information is available at:

• DOI Department Manual “305 DM 3”
• DOI Information Quality Standards
  • https://www.doi.gov/ocio/policy-mgmt-support/information-and-records-management/iq
• OMB Bulletin
  • https://www.bsee.gov/sites/bsee.gov/files/bsee-interim-document/oil-spill-response/omb-m-05-03-final-information-quality-bulletin-for-peer-review.pdf
• Executive Order 12866
  • https://www.epa.gov/laws-regulations/summary-executive-order-12866-regulatory-planning-and-review
  • https://www.archives.gov/files/federal-register/executive-orders/pdf/12866.pdf