Idaho is generally thought to be safe from the onslaught of the natural gas drillers, but in fact a portion of Eastern Idaho has the same geological structure as part of gas-rich Wyoming. The “Overthrust Belt” ranges of the Rocky Mountains run along the Idaho/Wyoming border. This intensely folded and even overturned area of thrust-faulting provides traps for hydrocarbons, mostly gas.
The Overthrust Belt is much more costly to drill than the Green River Basin to its east, which is seeing thousands of gas wells being drilled. The Overthrust Belt’s mountains ranges are also very scenic, have unstable soils and are tremendous wildlife habitat. Bad too is the fact that any gas found is likely to be “sour,” contaminated with rotten egg gas (hydrogen sulfide). Its use requires construction of huge sweetening facilities nearby to remove this poisonous gas before the natural gas can be used. In other words, development of the Overthrust Belt, is a nightmare; and it has proceeded slowly even in Wyoming.
Now smaller energy companies are applying for leases on the Caribou/Targhee National Forest in Idaho and that national forest is conducting an environmental analysis of the leasing proposal.
About 5 wells were drilled Idaho’s part of the Overthrust Belt back in the 1970s and early 80s. It is not known what they found. All were capped and abandoned. The drill pads were cleaned up, but some of the access roads remained open, including a road to the Black Mountain drill site on top of Black Mountain, just west of Alpine, Wyoming.
Geologists say that if there is gas in Idaho’s portion of the Overthrust, it is likely to be harder to find than in Wyoming, and even more poisonous because the natural gas would have been subjected to more intense pressure and heat in Idaho, these serving to alter its chemical composition.
Story from the Associated Press. Officials review energy drilling in Caribou National Forest.
Baldy Peak in the Snake River Range (Overthrust Belt). It’s just inside Idaho. The Snake River
Range was targeted by the gas industry in the 1970s and early 80s, although local conservationists
were able to keep them out of the most sensitive areas. Photo copyright Ralph Maughan