Disclaimer: If you can light your tap water on fire and you happen to live in close proximity to a fracking site, do consider the dizzying array of variables that can factor into the flammability of your water, such as the region in which you live and its unique subsurface characteristics, different companies’ drilling and well construction practices, naturally occurring methane concentrations, etc. As this article seeks to expose, natural gas can find its way into water wells in a multitude of ways unique to the situation in question.
The dramatic leap of flame seen in the video is not actually “water on fire”—in fact, it is the natural gas present in the water that is burning when lit by a match. The question then becomes, how did this natural gas get into the water? Was it a side effect of nearby drilling and fracking operations as purported by the popular videos “Gasland” and “Promised Land”? Or is it a natural occurrence?
Natural gas is a mixture of methane and small amounts of other hydrocarbons that is formed in the earth in one of two main ways. Biogenic natural gas is formed nearer to the earth’s surface as a result of microbial activity and metabolism. Thermogenic natural gas is formed at great depths as organic matter is broken down by chemical reactions triggered by heat and pressure. The two types of gas differ in composition as well as in location3. Biogenic natural gas is more likely to be found near the shallow aquifers targeted by private water wells while the deeper thermogenic gas is more often the target of drilling operations. However, the natural presence of both types of gas in groundwater is definitely possible and certainly not unprecedented.
Naturally occurring methane in aquifers can contribute to “water on fire”
The simplest explanation for the flaming water in Sherry Vargson‘s faucet is that her private well taps into an aquifer whose water contains dissolved methane. In other words, the gas had been there all along. Biogenic methane is produced at shallow depths by a large variety of species of microorganisms called methanogens3. Methanogens thrive at temperatures between 15 and 100 degrees Celsius meaning that they are often active and producing methane in rock formations that collect water at the same depths. This biogenic gas and water then accumulate in the same aquifer3. When a water well is drilled, tapping into the aquifer, both methane and water will begin to flow up the wellbore—and eventually out of a local faucet. In fact, a 2011 study by Duke University reported presence of methane in 85% of tested water wells in the Pennsylvania region—regardless of the proximity of oil and gas drilling6.
Natural methane seeps and “water on fire”
Natural methane seeps are also a fairly common phenomenon. Methane seeps occur when underground methane flows to the surface through naturally occurring fissures and pores in rock. If a water well is drilled near a natural seep site, it is quite possible for that methane to contaminate the intended drinking water.
Both biogenic and thermogenic methane seeps are well documented across the world and throughout history. In fact, before the advent of advanced geological studies and imaging techniques, the presence of natural seeps was the main indicator of underground reserves for oil and gas drilling prospectors. The first discovery of oil in the United States was actually made when explorers encountered the Seneca Oil Spring2. Called “the spring that blazes when a hot coal is applied” by the local Iroquois tribes, the Seneca Oil Spring is an example of natural “water on fire” dating from the 17th century2.
Indeed, natural seeps around the world gained widespread fame that predated oil and gas drilling by thousands of years. The legendary “Oracle of Delphi” of Greek literature, mythology, and historical record is in fact the site of a natural gas seep that created a “burning spring” where gases bubbled up and were released into the air4. The effects of the seep seemed mysterious to the ancient Greeks and the site was revered as the center of the earth and a mouthpiece of the Gods4.
Across the Aegean, in the modern nation of Turkey, the presence of perpetually burning natural gas seeps on a coastal hillside in the province of Antalya was first documented as long as 2,500 years ago5. As at Delphi, the ancient Greeks attributed mythical and divine qualities to the seep, building a temple to Hephaistos, the god of the forge, on the site. The light of the burning seeps on the hillside was also used as a landmark and natural “lighthouse” by ancient sailors. Pliny the Elder, a Roman author born in AD 23, named the site as the origin of the myth of the fire-breathing Chimera5. As a result, the location in modern Turkey is called “Mount Chimaera” and has been made a national park. Modern studies reveal the gas emanating from the seeps to be mainly methane gas with trace amounts of other hydrocarbons and inert gases5. Analysis of isotopic ratios in the methane has shown that the seep is made up of abiogenic and thermogenic gas5.
Natural gas migration can cause “water on fire”
It is also possible for natural gas to migrate through formations and into aquifer rock as the result of water drilling and production3. Even if natural gas is not present in the aquifer rock before the drilling of a water well, the gradual removal of water can encourage migration of natural gas nearby. Removal of water saturated into porous rock by a private well will lower the pressure in the aquifer. If natural gas is present in nearby porous formations, it may flow down the pressure gradient and into the targeted aquifer to replace lost water volume.
Coalbed methane causes of “water on fire”
A common explanation for methane that appears suddenly in previously pure drinking water is that the water well was drilled into a coal seam. Coal seams are common source formations of both water and methane and the two are almost always present in tandem1. Coalbeds exhibit properties unique from other reservoir formations that introduce special considerations into the production of both water and natural gas.
Unlike the natural gas present in most reservoir formations, the methane found in coalbeds is not simply saturated into the rock’s pores—it is actually chemically bonded to them. Coal is characterized by two levels of porosity: macropores and micropores1. While water generally fills the larger macropores, almost all natural gas is found bonded, or adsorped, onto the surface of the tiny micropores1. However, these bonds are not extremely stable. The adsorption of methane onto the micropore surface is dependent on sufficiently high pressures in the reservoir. If pressures drop below a critical point, the methane will begin to desorb—that is, it will release from the coal and become capable of migration1.
In undisturbed coal seams, these pressures are provided by the presence of water saturated into the macropores. When a coal seam is tapped by a water well, pressures will begin to drop as water is removed for human use. This phenomenon can cause the sudden “materialization” of methane in a water well. At first, while the methane remains bonded to the coal, the well will produce pure water without methane contamination. However, when the aquifer pressure drops beneath the critical point, desorption will occur allowing methane to flow upward along with the water. At the surface, it will seem that methane has suddenly “appeared” in the well.
Why is my water on fire?
The cases detailed above are all possible explanations for the presence of natural gas in private water wells and tapwater. However, this is not a complete list. Natural gas and methane contamination must be evaluated on a case by case basis. If methane contamination in conjunction with drilling near your home is a concern, water testing is vital to both prevention and determination of the cause. In the best case scenario, water testing should be performed both before and after drilling operations occur. If contamination is found, it is also important to test and examine the content and chemical characteristics of the natural gas present. Chemical and isotopic ratios of natural gas can help determine whether it is biogenic or thermogenic and also provide clues as to its place of origin.
1) Aminian, K. (n.d.). Coalbed methane: Fundamental concepts. Informally published manuscript, Petroleum and Natural Gas Engineering Department, West Virginia University, .
2) Ayala, S. (2011, November 29). The story of nys’s fracking moratorium. The Examiner
3) Grossman, E., & Coffman, K. (1989). Bacterial production of methane and its influence on ground-water chemistry in east-central texas aquifers. Geology,17, 495-499.
4) Hale, J. (2010, April). The delphic oracle: modern science examines an ancient mystery. Toledo museum of art lecture, Toledo, Ohio.
5) Olympos National Park. (2013). Ancient lycian ruins of the city of olympos: Yanartas.
6) Osborn , S., & et al, (2011). Methane contamination of drinking water accompanying gas-well drilling and hydraulic fracturing. Proceedings of the Natural Academy of Sciences,