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Management of Water for Hydraulic Fracturing Enhanced with the Expanded USGS Produced Water Geochemical Database

Abstract

Increases in hydraulic fracturing practices for shale gas and tight oil reservoirs have dramatically increased petroleum production in the USA, but have also made the issue of water management from these operations a high priority. Hydraulic fracturing requires ∼ 10,000 to 50,000 m3 of water per well for injection in addition to water used to drill the well. Much of the water used is potable fresh water. Concerns about groundwater depletion and contamination have prompted operators to increase the amount of produced water that can be recycled and to find suitable locations for salt-water injection. Knowledge of the geochemistry of produced waters can be valuable in determining how feasible it is to recycle produced water. Water with low salinity can be reclaimed for reuse outside of the petroleum industry (e.g. irrigation, drinking water, industrial operations). Water that has few scale-causing compounds can be reused in future fracturing operations. The updated and expanded USGS Produced Water Database will facilitate and enhance studies on management of water, including produced water, for hydraulic fracturing. The 2002 USGS database contains ∼ 60,000 data points. We are collecting data from publications, state oil and gas commissions, and petroleum companies, and expect to add at least 140,000 points for an approximate total of 200,000 data points. We have not only filled in state and regional gaps with conventional oil and gas well data, but are also adding information from unconventional wells and increasing the number of constituents to include minor and trace chemicals, isotopes, and time series data. In the case of data from unconventional sources of energy, we currently have procured produced water data analyses from 4,500 coalbed natural gas (CBNG) wells, 3,500 shale gas wells and 600 tight oil wells. These numbers are increasing as we continue to receive positive responses from federal and state agencies and petroleum companies wanting to contribute their data. This database will be an important resource for a wide range of interested parties. Scientists from universities, government agencies, public municipalities and citizens can determine the geochemical nature of deep groundwater supplies, contamination sources, and impacts of hydraulic fracturing. Petroleum companies can consult the database for determining the suitability of water reuse and for identifying regions where non-potable hydraulic fracturing water may be obtainable.