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Doyon studying Nenana prospects
Doyon Ltd is identifying new oil and gas leads in the Nenana basin from 3-D seismic that the Native corporation shot earlier this year, James Mery, Doyon’s senior vice president for lands and natural resources, told Petroleum News in an Aug. 14 email.
“The exceptional data quality from last winter’s 64-squaremile 3-D seismic program coupled with our initial interpretation and review has resulted in the identification of several new and additional leads, compared to what we had expected,” Mery said. “We are encouraged by this positive development with our Nenana basin program.”
The corporation had anticipated using the 3-D seismic to refine a couple of leads identified from 2-D seismic data gathered in the northern part of the basin in 2016. The idea was to refine a prospect with the intention of drilling a well, perhaps as early as the winter of 2018. However, given the time required to assess the new insights available from the 3-D data, Doyon, together with its partner Cook Inlet Region Inc., now anticipates making a drilling recommendation and decision by mid-November 2017, with a view to drilling in the summer of 2018 or the winter of 2018-19, Mery said.
“With these new data there is not enough time to conduct the deliberate data interpretation and evaluation necessary for good decision-making,” Mery said in reference to the earlier drilling plan.
Three wells drilled Doyon has already drilled three wells in the Nenana basin, a large sediment- filled trough southwest of the city of Fairbanks, as part of an exploration program, seeking oil and gas in the basin. Those three wells, the Nunivak No. 1, the Nunivak No. 2 and the Toghotthele No. 1, are all in the central part of the basin, where Doyon had hoped to find oil or gas that had flowed into a reservoir rock from a deeper source. The depths attained in the deeper sections of the basin are thought appropriate for the rocks to reach temperatures high enough for oil and gas to form.
In the event, although the wells failed to discover economically viable oil or gas pools, the wells did find ample evidence for an active petroleum system in the basin. In addition to natural gas in the form of methane, the wells encountered so-called “wet gases,” such as propane, butane and pentane. These materials typically indicate the presence of a petroleum system conducive to the formation of oil. The Toghotthele No. 1 well, drilled in 2016, found multiple oil shows in a situation where it appeared that oil had migrated through the rocks without becoming trapped to form a significant oil pool.
The new seismic data are revealing the structure of a deeper section of the basin, to the north of the three existing wells. Abundant coal seams in the basin are thought to be the primary source of hydrocarbons. The characteristics of the coal appear to be conducive to the formation of oil as well as gas.
The Nenana basin is conveniently located near the road and rail transportation corridor between Southcentral Alaska and the Interior, thus making the basin an attractive target for potential oil or gas development.
- ALAN BAILEY
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