I know, I know. Running a story about coal in an upstream oil and gas magazine is skirting close to sacrilegious. But as I see it, skirting the edge and considering all possibilities are what helped carry petroleum out of the dark ages and into the light where it could grow into the modern industry behemoth it is today. This particular story is one that demonstrates how, with a little collaboration, a possibility is considered and successfully tested.
In January 2017 the Alaska Department of Natural Resources (ADNR) released its initial findings of an investigation into assessing the liquid hydrocarbon potential of the state’s coal deposits. “While coal has long been considered an excellent source of natural gas,” the report stated, “…there has been much discussion as to whether, and to what extent, coal functions as source rocks for oil.”
The investigators acknowledged that there have been commercial discoveries of conventional oil having been correlated to coal source rocks; the Cooper and Eromanga basins in Australia and the Danish North Sea are just two of the many examples cited.
With this in mind, the Alaska Division of Geological & Geophysical Surveys and the U.S. Geological Survey (USGS) initiated a collaborative project to conduct experiments on selected samples of Alaskan coal to investigate the oil potential of the state’s vast coal resources. The coal samples were collected in 2015 from outcroppings at the Usibelli Group operation near Healy—near the Nenana Basin—and near Wishbone Hill in the Matanuska Valley near Sutton, according to a March 1 article on the investigation appearing in the Anchorage Daily News.
The samples were provided to the USGS by the state geologists, the article reported. The coal was mixed with water in a reactor vessel and superheated for three days in a process known as hydrous pyrolysis. Each submitted sample did produce oil. USGS scientists at the Denver laboratory produced 38 mg to 64 mg of oil from 1 g of coal, depending on the sample, the article stated.
It’s not much as the investigation was just the first in what could be many more steps. According to the ADNR report, possible future research will focus on conducting hydrous pyrolysis experiments on more coal samples from Alaska, including older coals from the North Slope, and on the conditions required for effective oil expulsion from coal.
Considering all possibilities is second nature in the petroleum-rich—but still very much a frontier—state, where being creative means survival.
Contact the author, Jennifer Presley, at email@example.com.