The Flaming Fountain is an important component of the South Dakota veteran’s memorial site at Capitol Lake next to the state capitol building in Pierre.
The Flaming Fountain is a water well that was drilled back in 1910 and completed in the Dakota aquifer at a depth of 1,280 feet. The well is uncapped and free-flowing, driven by artesian pressure in the aquifer. Until recently, enough natural methane gas was produced with the water to sustain a flame, giving the fountain its name. This flame no longer burns continuously, snuffing out within hours to days after being re-lit.
Stacy Langdeau, PE, state engineer and a South Dakota School of Mines and Technology graduate, inquired if the geology and geological engineering department at SDSM&T had any interest in investigating the now non-Flaming Fountain. Coincidentally, a methane sensor had recently been transferred to SD Mines from the U.S. Department of Energy to investigate the occurrence of stray gas in drinking water aquifers in the vicinity of fracked shale gas wells. No place had been identified to field test it.
After Dr. Foster Sawyer and ERI Director Dan Soeder visited with the state engineer, she cleared the way with the governor for SD Mines to monitor the methane output of the Flaming Fountain well. This was the perfect site to field test the sensor, because at least some methane was known to be in the well. Daniel Lucas and Logan Kocab, GGE undergraduates, then took on the Flaming Fountain as a senior research project. Daniel focused on the instrumentation aspects, and Logan focused on the geo-hydrological aspects. Geology graduate student Disha Gupta led the overall project effort. With the assistance of Dr. Dan Dolan at the Center of Excellence for Advanced Manufacturing and Production (CAMP), the students were able to re-design and construct the unit within a few short weeks for deployment at the Flaming Fountain.
The electronics of the methane sensor consist of an Axetris solid state device that uses a laser tuned to the adsorption wavelength of methane, and measures concentrations by the attenuation of the beam. A Campbell Scientific electronic data logger and programmable controller operates the laser unit. The Axetris sensor was designed for use in a laboratory environment under controlled climate conditions with clean line power and an adjacent laptop computer to collect data. Adapting it for use on a wellhead in the field was a significant technical challenge. Power management was a major concern, especially after the DOE engineers found out the hard way that turning off the sensor between readings to save the battery ended up burning out the laser. As such, the device had to remain powered-on when taking readings. Both Saeed and Sandesh did an admirable job of addressing the power supply and power management issues.
Daniel Lucas led the re-design of the external unit, including the weather-tight cabinets and supporting structures. He tried to re-use as much of the original DOE materials as possible. Logan Kocab investigated the history of the Flaming Fountain well, discovering the original drilling records and well logs at the South Dakota Geological Survey.
The methane sensor was deployed on the Flaming Fountain well on Sunday, March 24, 2019. All four students: Sandesh, Disha, Logan and Daniel gave up their Sunday to get the instrument into the field. Tellingly, the students had asked to go to Pierre on a Sunday to install the unit instead of a weekday so they wouldn’t have to miss class. The unit was set up in a grassy area alongside the Flaming Fountain walkways and steps. A length of ¼ inch nylon tubing was run from a clamp on the fountain casing to the detector. A sign is displayed on the upper cabinet explaining what is being done and why. The plan is to leave the unit on the fountain until autumn and collect data over the summer.
Long-term measurements of the amount of methane produced by the well may help GGE researchers advise the state engineer on some ways to bring the flame back to the Flaming Fountain. Ideas include re-completing the well in the Dakota aquifer with a horizontal borehole to intercept more methane or adding a lateral borehole in another formation known to be gassy, such as the Niobrara above the Dakota aquifer. Defining the trends of methane production in the current well over time may provide a clearer picture of why the Flaming Fountain no longer flames.