Produced-Water-Volume Estimates and Management Practices

Abstract

Summary Produced water is the largest byproduct stream associated with oil and gas production. Within the United States, nearly 1 million oil or gas wells are producing hydrocarbons with various volumes of produced water. In the past, several estimates of the annual volume of produced water have been made, but none are highly accurate, nor are they current. This paper describes a study conducted by Argonne National Laboratory for the US Department of Energy (DOE) in 2009 to develop accurate estimates of produced-water volumes for 2007. The estimates were developed through contacts with regulatory-agency representatives from each of the 31 states that produce oil and gas, as well as several federal agencies that oversee onshore and offshore production on federal lands. A few states maintained detailed records of produced-water volumes, many provided estimates from underground injection records, and a few do not maintain accurate records for estimation. For those states, estimates were developed using various extrapolation methods. Where possible, the produced-water volumes are provided separately for different hydrocarbon types (i.e., crude oil, conventional gas, coalbed methane, tight-shale gas). This allows calculations of water/hydrocarbon ratios for different states and different hydrocarbon types. In addition to providing a recent accurate volume estimate, the paper discusses the ways in which the produced water is managed in the different states and in the US offshore. While much of the onshore produced water is reinjected for enhanced recovery or disposal and much of the offshore produced water is discharged to the ocean, various other methods are used also. The Argonne study and this paper provide the most-complete and -recent picture of produced-water management in the United States.