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A line of trucks carrying water to Natural gas rigs make their way across the sprawling network of two lane roads between small towns to make almost constant deliveries to continue the hydraulic fracturing process used to gather natural gas in Monroeton, Pennsylvania, January 13, 2013.
Credit: Reuters/Brett Carlsen
The biggest product of the U.S. petroleum industry is not oil, gas or condensate but water — billions and billions of gallons containing dissolved salts, grease and even naturally occurring radioactive materials.
In 2007, when the shale revolution was still in its infant stages, the U.S. oil and gas industry was already producing more than 20 billion barrels of waste water per year, according to researchers at the Argonne National Laboratory (“Produced water volumes and management practices in the United States”, 2009).
The industry’s daily output was 5 million barrels of oil, 67 billion cubic feet of natural gas, and 55 million barrels of water, according to federal government statistics.
Argonne estimated that more than 7.5 barrels of water were produced for every barrel of crude, and 260 barrels of water for every million cubic feet of natural gas, based on state and federal records for onshore oil and gas production.
If offshore production is included, the figures drop slightly to 5.3 barrels for every barrel of crude and 182 barrels for every million cubic feet of natural gas.
But all these numbers are likely to understate the water-to-oil and water-to-gas ratios, since some of the most important states, including Texas, did not report their production statistics in sufficient detail to compute ratios accurately.
Older wells produce a higher proportion of water, so states with a long history of oil and gas production and large numbers of aging stripper wells tend to have the highest volumes of water production and the highest water-to-oil and water-to-gas ratios.
The five old oil- and gas-producing states of Texas (7.4 billion barrels of water), California (2.6 billion), Oklahoma (2.2 billion), Kansas (1.2 billion) and Louisiana (1.1 billion) accounted for almost three quarters of water production in 2007.
California oil wells produced more than 10 barrels of water for every barrel of oil, rising to 22 barrels in Kansas and 43 barrels in Illinois. In contrast, North Dakota reported just 134 million barrels of produced water in 2007, an average of three barrels of water for every one of oil.