Methane (natural gas) from coal beds has long been a source of clean energy. Abundantly available, it burns cleanly and requires minimal processing to be used as a fuel. However, a supply problem is developing. Coal beds have a limited supply of the gas, and it take a long time to recharge the reservoirs. Gas drilling companies initially make large profits on the gas, because it essentially pumps itself out of the wells. After a time, however, the pressure of the gas drops to the point where it no longer makes sense to keep harvesting it.
Luca Technologies is a company that has invested heavily in a process that they hope will enable gas companies to literally farm methane. Dr. Joel Sevinsky, the Senior Principal Investigator at Luca, presented the technology from a microbiologists’ point-of-view.
Sevinsky pointed out that companies are required by law to close down their gas well operations when they cease to be profitable, and that Luca has developed a technology that he hopes will extend that profitability considerably. “Many hydrocarbon reservoirs are alive with microbes,” he said, to dispel any thoughts that coal beds are dead. “These reservoirs can be enlivened with nutrients to generate natural gas in real time,” he added. Natural gas can be literally farmed.
The process of natural gas farming is fairly simple. First, the coal bed is drilled and the casing is dropped into the bore hole. Then, concrete is pumped around the outside of the casing, sealing the well. Water is then pumped out of the hole, and the lower pressure allows the methane gas to seep out of the coal and be collected at the well-cap. The technology that Luca is implementing involves drilling another well in the same manner, but instead of water being pumped out, water that is packed with nutrients and minerals to re-enliven the microbes in the coal is pumped in. These microbes then produce methane at a rate much greater than natural processes.
What is actually happening, Sevinsky explained, is that the natural process of reservoir restoration is being mimicked. The natural process takes thousands of years, however, and Luca is doing it in a matter of months. The primary focus at Luca right now is understanding the differences between various wells in terms of the microbial community, and figuring out more efficient and environmentally-conscious ways of producing natural gas.