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Nenana well nearing its targets
As Doyon’s Toghotthele No. 1 exploration well in the Nenana basin approaches its drilling targets, Doyon Ltd has filed a plan for a second well this summer from the same drilling pad, should the first well encounter a significant hydrocarbon resource. James Mery, Doyon vice president for lands and natural resources, told a press briefing on June 22 that the Native regional corporation had started drilling the Toghotthele well early in the season, on June 1, to allow time later in the season for well testing and for drilling that second well if appropriate.
“We wanted to get an early start because we’re really constricted on the tail end of the project,” Mery said, commenting that a barge crossing of the Nenana River needed for site access becomes impossible when the river level drops later in September.
The primary purpose of drilling a second well would be to confirm and delineate a gas discovery, to provide some certainty about the gas potential of the prospect that Doyon is testing, and to accelerate gas development, should there prove to be a viable find in the well currently being drilled, Mery said.
Casing the well On June 22 the drilling operation had paused for a few days at a depth of 6,394 feet while the drilling crew placed intermediate casing into the well bore, before proceeding to the planned total depth of 10,000 feet. The drilling targets are within that depth range of about 6,400 to 10,000 feet, Mery said.
The Toghotthele well is the third well since 2009 that Doyon has drilled in the central part of the Nenana basin in a search for oil and gas. The Native regional corporation has found evidence of the existence of both natural gas and liquid hydrocarbons in the basin. Mery said that the second of Doyon’s Nenana wells, the Nunivak No. 2 well, drilled in 2013, encountered a significant quantity of gas over a vertical interval of about 400 feet. However, the water content of the reservoir rock was too high for commercial gas production - it appears that much gas originally in the reservoir had leaked out through a fault zone that marks one side of the underground hydrocarbon trap, Mery said.
The gas discovered was so-called wet gas, gas containing both methane and natural gas liquids such as propane. This indicates a thermal rather than biogenic source for the hydrocarbons. Thermally generated hydrocarbons could include oil.
- ALAN BAILEY
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