Coal Bed Methane as a local fuel source for Galena
3-28-08
Tim Bodony (KIYU) 

Original audio version, as broadcast on KIYU on March 28, 2008 

A search for possible coal bed methane reserves beneath Galena and surrounding area is poised to begin.   

The gas could be used instead of diesel fuel to run generators at the city power plant.   

Coal is visible at several outcroppings across the middle Yukon valley, including spots just west of the Yukon River near Nulato, and near the old Louden village site upriver from Galena.   

The evidence of coal has led some to question how extensive the coal deposits are underground, and whether that coal is accompanied by methane. 

Geologist Art Clark from the US Geological Survey, based in Denver, is heading up the preliminary effort to find and measure the coal and coal bed methane resource around Galena.   

At a Galena Breakfast Club meeting Thursday morning, Clark explained that the USGS, in partnership with BLM, has a project to look beneath the earth’s surface for alternative energy sources for Alaska villages.   

Clark: we are funded by USGS and BLM to go and do initial field work.  But we are not funded to do expensive exploratory projects.  We’ve worked in Fort Yukon and currently in Wainwright, providing technical expertise and equipment and the access to that, but different entities have to put together proposals to fund drilling and research programs if it were to go that far.    

Galena officials say they will pursue state funding for the next steps in the process to explore for coal bed methane, possibly tapping into a 250 million dollar renewable energy fund proposed by Governor Palin. 

Clark stressed that while subsurface methane holds some promise as an energy source for this region, the mining of coal would be nearly impossible, due primarily to geological influence of the Yukon River.   

Clark: it’s not like we have chunks of coal and we are going to burn them.  You have this thick deposit of wet sand and gravel, very unconsolidated and it has a lot of water going through it because of the river, and there is no way you could put a shaft down because it would keep collapsing and filling in on you. You would have to drain the Yukon River to get that thing to stay. And it would be so expensive that it would not be feasible.  If it ever comes down to a coal mine, understand that is not what we are looking at here, you would have to dig [the coal] where it is exposed at the surface.   

Coal bed methane development has been controversial across the country, Clark says, due in large part to massive, under-regulated drilling and extraction in states like Wyoming and Montana.   

Proposals to extract methane in the Mat-Su Borough about 5 years ago set off a firestorm of resistance from local residents, when it was announced that drilling could occur on private property to get at gas underneath it.   

Extracting methane also involves pumping out groundwater, and in some cases that water can be high in salt content and lead to environmental damage if it escapes containment. 

But Clark cautioned that every project is different, and that in most cases, like a test project he is also working on in Wainwright, little if any water will have to be kept at the surface. 

Clark: there are a lot of horror stories out there about coal bed methane, and most of them come from the Powder River basin in Wyoming, which is a classic example of how you should not produce [coal bed methane] because there have been a lot of misunderstanding and a lot of problems.   

One of the problems with the Powder River basin in particular is that these coals are holding gas, but the amount of gas they are holding takes a lot of water being pumped off, pressure being taken off of [the gas].  They have to pump huge amounts of water, and they are just running it on the surface. And it’s actually fairly good water.  Most coal bed waters are pretty saline or brackish – not anything you want on the surface.  Typically, they have one central reinjection well, and they pump the water from these wells over to the re-injection well and goes back into the ground into another aquifer further below the coal seam.   

In Wainwright, those coals are holding as much as they can possibly hold, and then some.  So in theory there is probably some free gas and before we pump any water, there should be some gas coming off.  So it just goes to show that you can’t go into a basin and know [how much water will need to be pumped out] ahead of time. That’s why we do this drilling.   

Clark couldn’t pin down how many wells would be needed around Galena to produce enough gas to run the city power plant, but predicted that the number would be less than 10. 

Using only a few wells, combined with the fact that it would not be a profit-making venture, would make a Galena coal bed methane project more environmentally-friendly, and sustainable, according to Clark. 

Clark: At the Powder River Basin, there are thousands and thousands of wells.  Because they are trying to get as much gas out, as quick as they can, because they are selling it on the commercial market.  It is in their benefit to get it out as quickly as they can, so they put the wells fairly close together and just pump it all out, and when they are done they just move someplace else.  But keep in mind for what you are talking about here, which is local use, you don’t want to get a whole bunch of gas out real fast.  What you want is a slow, steady stream of gas coming in.  What they use commercially really has no bearing on what you are talking about here. The slower you pump [the gas] the fewer [wells] you would have to put in, because over time a hole can drain a larger and larger area.   

A simple seismic test done close to 7 years ago was inconclusive about subsurface coal deposits around Galena.   

USGS has done chemical tests on coal from the outcropping near Louden, and found it to be of relatively high quality, and potentially rich in methane.   

But geologists don’t know how much coal is beneath the surface…how deep the coal is…and how the coal seems are shaped.   

To get some answers to those questions, University of Kansas research geologist Rick Miller has teamed up with the USGS crew, and is proposing some high-sensitivity seismic testing.   

Miller explained that the equipment works essentially the same way as a fish finder.   

Miller: you are sending sound waves down, and you are trying to find the fish.  The fish here is the coal.  Now, we can’t tell what kind of fish it is, but we can tell it is a fish.  So in this case, with seismic, we can’t tell if it is coal, but we can tell it is a rock layer, and we can tell what the geometry of the rock layer is, and from that, with the geologists’ information, we put together a best guess as to what might be going on, and pick the ideal location to put down a drill hole. 

Most of the land on which coal exploration would occur around Galena is owned by Gana A’Yoo Limited, with the subsurface development rights held by Doyon Limited. 

Seismic testing for Galena coal seems could happen as soon as next spring, if funding comes through.   

The geologists are also entertaining the possibility of doing seismic testing beneath the Yukon River as soon as this summer, using equipment that can be pulled behind a boat.   

Data collected from the river tests could be used as a comparison to the land-based seismic tests, but if they reveal coal directly underneath the river bed, Clark says that diagonal drilling methods could be used to access it.