The goal of this project is to help oil and gas operators increase production, decrease costs, and enhance environmental protection in the shale gas producing states of New York, Pennsylvania, West Virginia, Arkansas, Louisiana, Oklahoma, and Texas that encompass regions containing the Marcellus, Haynesville, Fayetteville, or Woodford shale formations. The objective is to create an internet-based water treatment technology catalog and decision tool that will pair an operator’s water treatment costs and capacity needs to optimal water treatment technologies. The catalog will identify produced water treatment options by region and water quality and quantity limits. The decision tool will help an operator choose from the best treatment options based on site specifics such as contaminants, desired resultant water quality, final use options, efficiency, and cost.
Arthur Langhus Layne LLC /dba ALL Consulting
Ground Water Protection Council (GWPC)
The predominant limiting factor to development of coal-bed natural gas and gas shale basins nationwide is the management of produced water. The challenges of produced water management in many of these basins include increased water volumes, limited water disposal options, determination of applicable water management and treatment options, availability and cost of water treatment, local need to ensure beneficial use, and identification of possible end-users of the water. Additionally, environmental sensitivities such as aquifer drawdown/recharge, potential impacts to soil productivity, and changes to aquatic ecosystems have caused the natural gas industry to look to water treatment as an option to manage produced water.
The decision process for determining the most suitable water treatment technology continues to be a source of concern as there are many complex variables that contribute to the success or failure of produced water treatment technologies. Produced water treatment has seen a surge in research and testing by an assortment of water treatment companies and technical researchers. A relatively broad array of produced water treatment technologies are available for commercial use in the upstream oil and gas industry, but many of these technologies have limited commercial history and their performance in the field is unproven. The lack of clarity on technical aspects of various treatment methods and their respective applicability, along with cost and other factors that impact the decision making process, are impeding the treatment of produced water on a national scale, which in turn is negatively impacting the production of natural gas resources in many existing and emerging basins nationwide.
In many instances, the produced water is wasted through disposal into deep saline aquifers rather than being put to beneficial use. Many operators have opted not to pursue beneficial uses of their produced water either because they don’t have time to research the myriad potential use options and treatment technologies or are simply not aware of the alternatives that may be available to them. Others have pursued treatment options that in the end were not cost-effective or did not result in the water quality needed, in part because they did not initially consider all of the factors involved in the decision. Operators have also experienced regulatory penalties and fines, due, in part, to their lack of understanding of current laws and regulations that are constantly being updated by state regulatory agencies in an attempt to protect the environment.
Considerations such as availability and costs of associated chemicals may limit certain water treatment options. Specific water quality parameters may also eliminate particular treatment or water management alternatives. Further, long-term sustainable production volumes could create opportunities that may not be available to shorter-term resource plays. The considerations are complex and the risks are high. Most of the existing expertise with regard to water treatment lies primarily within the municipal and domestic arenas. Managing municipal water systems can be substantially different than managing water produced in association with oil and gas wells. Municipal systems are designed for consistency, with a specific water quality and quantity in mind. In mineral production, water quality and volumes change, and wells go on and off line, and the relationship of these changes to specific applications must be understood in order to realize success.
Cataloging existing and emerging produced water treatment technologies will help operators to identify the most cost-effective approaches for managing their produced water. Industry decision makers with operations in unconventional natural gas basins will gain relevant information on regulatory and legal issues that may impact the success of their projects. Oil and gas production will increase as cost-effective approaches to meeting water use and discharge requirements allow permits to be issued in areas that have been effectively off-limits because of regulatory requirements. Production increases will also occur because the reduced costs of water management will extend the economic life of each well and will free up capital for additional development. Environmental protection issues will be addressed by ensuring that all constituents of concern are identified and any waters that are released to the environment meet applicable standards.
A presentation entitled “Treatment of Shale Gas Produced Water” was given at the GWPC UIC Conference in Austin, TX on January 24, 2011, and a presentation entitled “Treatment of Shale Gas Water for Surface Discharge” was given at the EPA Techline Workshop March 29–30, 2011, in Washington DC. The Workshop was held as part of the EPA’s study of hydraulic fracturing.
ALL Consulting posted the Decision Tool application to the internet on January 31, 2011. The application is being tested internally and by the Project Advisory Council (PAC). Regulations in eleven states in the Marcellus, Barnett, Haynesville, Fayetteville, and Woodford shale play regions have been studied for state-specific water limitations and regulatory water quality limits. Publically Owned Treatment Works (POTWs) are also considered options for disposal in Pennsylvania and Arkansas when available.
ALL Consulting has outlined the initial system design, which allows the operator to enter data such as produced water quality and quantity, location, and possible end uses for the treated water. The tool will evaluate treatment and disposal options and a ranked list of selections will be generated based on treatment performance and treatment and disposal cost. Existing legal and regulatory requirements will be considered for each project location. The operator will be able to evaluate treatment options based on economic, environmental, and regulatory factors.
ALL has developed a Mixing and Scale Affinity Model for the Decision Tool which will allow operators to evaluate the amount and type of scale inhibitors that must be used to avoid scaling. The model will also allow operators to determine the maximum amount of produced water that can be mixed with fresh water to achieve the desired water quality. The Mixing and Scale Affinity Model and user guide are available online for download at the project website: http://www.all-llc.com/projects/produced_water_tool/ [external site].
Researchers have completed collecting data related to water treatment technologies, and have completed an investigation of water demands in unconventional basins. This data will be used to assess the potential for beneficial uses in areas where produced water treatment is economical or where no treatment is required.
The Ground Water Protection Council (GWPC) collaborated with the PAC to identify sources of data on regulatory and legal issues related to produced water treatment. Researchers examined existing regulations governing water treatment and have outlined possible changes to these regulations in order to identify any regulatory barriers that may impede the use of innovative and emerging technologies. Researchers also examined legal issues involving water rights to determine the legal implications of using treated produced water for beneficial uses.
The project ended on March 31, 2012. The final Report is available below under "Additional Information".