Field Research Using Herders to Advance In Situ Burning

Scope of Work

The contractor for this project was SL Ross Environmental Research Ltd. The University of Alaska (UAF) provided contract support, weather monitoring (wind, temperature and flying conditions), test pond infrastructure, site access, certificates to fly robotic helicopters, and necessary permits.

Task 1: Obtain Necessary Permits

University of Alaska Fairbanks (UAF) had primary responsibility, with SL Ross providing technical support where necessary, e.g. acquiring all permits required for the experiment including site approval, test basin construction, conduct of the burns, and disposal of any test materials.

Task 2: Construction of Test Pond

Completed view of test basin (© Geophysical Institute Design Services of the University of Alaska Fairbanks)

Completed view of test basin (© Geophysical Institute Design Services of the University of Alaska Fairbanks)

UAF oversaw the construction of a large, above-ground fully lined test pond (90m x 90m x1m deep) at a previously cleared site in the Poker Flat Research Range (PFRR). This is an extensive land area (thousands of acres) managed by the University of Alaska Fairbanks (UAF) ~ 50 kilometers (31 miles) northeast of Fairbanks, Alaska, USA.

Installation of the Geotex 801 fabric and XR-5 8218 Low Temperature Geo-membrane liner material to the test tank.

Installation of the Geotex 801 fabric and XR-5 8218 Low Temperature Geo-membrane liner material to the test tank. (© Geophysical Institute Design Services of the University of Alaska Fairbanks)

 

This is a 90-degree panorama from the North corner of the test tank showing installation of the double liner. Geotex 801 fabric is first installed and then XR-5 8218 Low Temperature Geo-membrane liner material is installed on top of the Geotex fabric for additional protection.

This is a 90-degree panorama from the North corner of the test tank showing installation of the double liner. Geotex 801 fabric is first installed and then XR-5 8218 Low Temperature Geo-membrane liner material is installed on top of the Geotex fabric for additional protection. (© Geophysical Institute Design Services of the University of Alaska Fairbanks)

Task 3: Develop an overall project management plan, test plans, and HSE plans for the experimental releases

An overall project management plan was developed by the research team based on a phase-gate model. The model included clear decision points along a timeline to approve moving to the next phase. A key component of the overall project management was the HSE plan that covered all identified hazards and their mitigation. This plan went through several stages of internal review and approval before testing began (more details are available in Section 7 of the final project report).

Task 4: Preliminary lab-scale testing of herders prior to the experimental release

Prior to the experimental release, SL Ross performed laboratory scale experiments to verify that the test oil (Alaskan North Slope crude) was amenable to herding and burning when fresh, and after weathering for a specified time. Tests also documented that the herders were equally effective in fresh water and salt water, allowing the full-scale tests to be performed in fresh water without loss of technical integrity.

Task 5: Operational readiness of aerial herder application and slick ignition systems

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Prototype herder delivery system for use in a manned helicopter. © DESMI AFTI

Helicopter-based herding/ISB required both a herder delivery system and an ignition source on the helicopter(s). In a previous project funded by ExxonMobil, DESMI AFTI built a prototype herder delivery system for use in a manned helicopter. That project culminated in successful static testing from a crane. The JIP carried the project to the next logical step in the development process by funding actual airborne tests to verify the spray pattern and confirm that the system met the requirements for field testing in Alaska.

Task 6: Field Experiments

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Ignition of the herded oil slick using a Heli-torch™. © SL Ross Environmental Research Ltd.

During late April 2015, five tests were conducted at the Poker Flat test pond to determine if a helicopter could be used to first apply herding agents to crude oil slicks in simulated drift ice conditions and then to ignite the herded oil slicks using a proven aerial system, the Heli-torch™. After several initial attempts failed to accomplish ignition due to issues with the gelled fuel consistency, two successful in-situ burns were accomplished using the combination of aerial herder application followed by ignition. One burn was accomplished with OP-40 herder and one with ThickSlick 6535 herder. The burning of the free-floating slicks resulted in the removal of approximately 70 to 85% of the oil on the water surface. The potential for using a robotic helicopter UAV to both spray herder and deploy a modified-flare igniter was demonstrated during the test programme and verified in subsequent experiments in Ottawa. The entire programme was free from any reportable HSE incidents.

The final project report is available on the website. A number of conclusions and recommendations were drawn from the testing programme including:

  • The application of herders and subsequent ignition of free-floating oil slicks from a helicopter was successfully demonstrated in two tests.
  • Both OP-40 and ThickSlick 6535 were effective in controlling the thickness of the floating oil spill.
  • Laboratory tests documented that the herders were equally effective in fresh water and salt water, allowing the full-scale tests to be performed in fresh water without loss of technical integrity.
  • An operational herder / igniter concept needs to have the capability for herding and igniting in a single flight without the need to land in between activities.
  • Offshore field trials of the concept are necessary in order to allow extra time for herders to act on the slick. This will allow better estimates of likely oil burn efficiencies achievable with this countermeasure and the weather windows for its effective use.
  • The UAV herder application system and flare ignition system were successfully demonstrated, but additional work is needed to refine, and perhaps combine these technologies for commercial use.
  • Further work on UAVs is also warranted as a platform to collect fire area data, not only in an experimental setting but also during an actual operation. This information can enable more accurate estimates of burn rates and volumes of oil consumed, and would help responders monitor the progression of a burn and develop a database of total volume consumed in a series of burns.

Task 7: Write technical report, peer-reviewed scientific paper and technical presentation.