Energy Policy Act of 2005 (Ultra-deepwater and Unconventional Resources Program)
An Integrated Framework for the Treatment and Management of Produced Water
This project seeks to develop an integrated decision framework that can be utilized in the management and treatment of produced water, resulting in a significant reduction in overall costs and enhancement of gas recovery related to coal bed methane and gas shale fields.
Colorado School of Mines, Golden, CO 80401-1887
Kennedy/Jenks Consultants, Inc., San Francisco, CA 94107
Argonne National Laboratory, Washington, DC 20024
Pioneer Natural Resources, Denver, CO 80202
Chevron, Richmond, CA 94802
Marathon Oil Company, Houston, TX 77056
Anadarko Petroleum Corporation, Denver, CO 80202
Pinnacle Gas Resources, Sheridan, WY 82801
Petroglyph Operating Company, Inc., LaVeta, CO 81055
Water Research Foundation, Denver, CO 80235
Eltron Research and Development, Boulder, CO 80301
Hydration Technologies, Albany, OR 97322
Southern Nevada Water Authority, Las Vegas, NV 89106
Stewart Environmental Consultants, Fort Collins, CO 80525
Triangle Petroleum Corporation, Calgary, AB, Canada T2P 3T3
Trout Unlimited, Jackson, WY 83001
Veolia Water, Cary, NC 27513
Contributions from unconventional gas resources to the nation’s energy supply have grown significantly over the past 20 years and demand is expected to drive future growth. With an estimated 293 trillion cubic feet (TCF) of technically recoverable gas from gas shale, coal seams, and tight sands in the lower 48 states, the resources are available to meet future demand. In order to meet this demand, solutions that reduce the amount of water produced are needed.
For proper gas well development in coalbeds water must be pumped out of the formation (dewatering) in order to reduce reservoir pressure and allow the methane to desorb. The co-produced water generated during these operations is by far the largest volume byproduct or waste stream associated with gas production. In contrast to conventional oil and gas production, the produced water from a coal bed methane (CBM) well is pumped in large volumes in the early stages of production and is typically at full pump capacity for up to two years. The quantity of water produced during the life of a well can be 1 to 3 bbl/mcf of gas. If an operator cannot sufficiently minimize water management costs, the CBM resource cannot be developed.
Water can also be produced from gas shale formations, and because of the massive fracturing treatments required to complete shale wells, there are significant volumes of frac treatment flowback water and produced formation water that must be handled for every completed shale well.
Where proper management of produced water cannot be cost effectively accomplished to meet regulations/permits or surface owner requirements, produced water issues can restrict current gas production or intended expansions.
This project will develop an integrated guidance framework that will link the composition of produced waters to beneficial use applications and identify the most cost-efficient, most environmentally sound, and most beneficial strategies for management and treatment of produced water from CBM and gas shale operations by taking into account the conditions in place in the field. This will be accomplished by cost-benefit analyses and life-cycle assessments that consider both technical and non-technical factors.
This site-specific approach will identify potential combinations of treatment processes which can potentially minimize the volume of residual concentrated brines by considering both well-established and emerging desalination technologies. The project will bring together gas producers, members of the water treatment industry, regulatory agencies, tribal interests, landowners, agricultural stakeholders and environmental groups to identify solutions to the institutional impediments to beneficial use of treated water. Input from industry and environmental groups in particular will be solicited, with suggestions being applied to the development of the integrated framework. A number of project performers will have specific responsibilities, in addition to providing financial support, staff time and travel, including:
- Framework development, water quality monitoring and analysis, testing equipment, technology transfer, and project management and oversight (Colorado School of Mines)
- Framework development, technology transfer (Kennedy/Jenks Consultants)
- Framework development, testing equipment, and technology transfer (Argonne National Laboraotory)
- Water quality and operational data (Anadarko, Chevron, Pioneer Resources, Marathon Oil, Petroglyph Operating Company, Pinnacle Gas Resources, and Triangle Petroleum)
- Water quality data and technical support during field trials (Pioneer Natural Resources)
- Expertise (Petroglyph Operating Company, Water Research Foundation, Southern Nevada Water Authority, Stewart Environmental, Trout Unlimited, and Veolia Water)
- Testing equipment (Eltron Research and Development)
- Membrane equipment support (Hydration Technologies)
The guidance framework developed during this project will assist producers in selecting the most economically and environmentally sound treatment processes suitable to the specific chemistry of the water that is being produced. The framework will also enable more accurate budgeting of produced water management costs for the producer. These advances will enable producers to utilize lower cost and better tailored water treatment processes and management alternatives potentially resulting in an increase of gas production.
Work on this project began on September 12, 2008 and the following accomplishments can be reported.
- The Technology Status Assessment (Task 2) describing the state-of-the-art of the proposed technologies was submitted in October 2008.
- In support of Task 7, the first Stakeholder Advisory Committee (SAC) workshop was held on September 25-26, 2008 to initiate a dialogue with key stakeholders regarding barriers to beneficial use of produced water. The second SAC meeting took place on August 26-27, 2009 in conjunction with the first meeting of the project’s Industry Advisory Council (IAC) to introduce and discuss the key elements of integrated framework approach and encourage collaborative interaction between industry and stakeholder representatives.
- The team completed a first draft of the Treatment Technology Assessment Report as part of Task 4 providing a cornerstone for the Integrated Decision Framework (Task 7). The draft document has been reviewed by the team’s technical senior advisors and members of the Industry Advisory Council.
- The team has developed water quality database for individual basins. These databases are augmented by water quality information available in the public domain and information provided by industry partners of this study that are engaged in operations in these basins.
- CSM has built a comprehensive database of currently employed water treatment technologies for produced water as well as technologies that are either emerging in the desalination of saline water or are employed elsewhere to treat brackish water types. More than 50 individual processes were identified and are currently reviewed. In order to rank these treatment processes under the scope of this study, assessment criteria were developed.
- The team finalized a beneficial use matrix detailing the water quality requirements for beneficial non-potable and potable uses by considering state specific requirements. This document is limited to requirements set forth by states in the Rocky Mountain region.
- The team developed a draft MS Excel based spreadsheet model that integrates water quality information, selection of treatment processes, beneficial use options, and an economic assessment. The draft spreadsheet model is currently refined and reviewed by the project team and is being tested by a select audience (IAC and SAC members) prior to going public in the fall of 2010.
- The team developed a beta-version project website that will serve as clearinghouse for project technology transfer and dissipation of information. The project website is http://aqwatec.mines.edu/produced_water/index.htm [external site].
Work has been completed in Task 2 (Technology Assessment Report). Work has begun on six of seven remaining tasks: the development of the Project Management Plan with work breakdown structure that concisely addresses the objectives and approach for each task with all major milestones and decision points (Task 1), technology transfer related to a website design, structure and knowledge integration (Task 3), water quality surveys using public domain databases and information provided by industry partners to identify variability and key constituents of produced water types (part of Task 4), a comprehensive and critical review of various treatment technologies for produced water (also part of Task 4), a beneficial use matrix including key water quality requirements (also part of Task 4), testing and evaluation of produced water treatment processes (Task 5), development of the core structure of the integrated decision framework for management and treatment of produced water (Task 7), and validation of the integrated decision framework through case studies (Task 8). The remaining task (Task 6) to validate key treatment processes during field testing is scheduled to begin in May 2010. The key tasks to be undertaken following the submission of the Project Management Plan are outlined below.
Classification of Produced Water Types, Treatment Technologies and Management Strategies (Task 4) -
The project will initiate a comprehensive compilation of data on both qualities (composition) and quantities of produced water associated with unconventional gas operations (CBM and gas shale) as well as background basin and watershed quality data in the Western U.S. The key objective of this phase is to categorize produced water types into groups of different but representative water quality compositions and to quantify the volume of water produced per basin. This assessment will occur in close collaboration with participating industry partners and is essential in identifying viable management and treatment strategies for beneficial use. This task has five subtasks:
- Produced Water Quality Categories - The quality and presence of specific constituents in produced water will dictate the selection of pretreatment, treatment, and post-treatment technologies suitable for achieving water quality goals. During this task, the research team will characterize and classify CBM and gas shale produced waters into different categories of treatability considering key water constituents. A categorization system for CBM and gas shale produced water qualities will be developed considering low, moderate, and high levels (i.e., >5,000, >10,000 and >30,000 mg/L) of total dissolved solids (TDS), predominant salt make-up (e.g., sodium chloride vs. sodium bicarbonate), presence or absence of hydrocarbons, and presence or absence of key constituents that might affect the viability of certain treatment options (e.g., hardness, H2S, temperature, fracturing chemicals). Water quality data will be gathered from public domain databases and augmented by using comprehensive water quality data sets provided by industry partners for specific basins.
This effort will enable the development of correlations among water quality, type of operation, location, depth, and age of a production well. Treatment goals will be defined and will consider both potable and non-potable standards for beneficial uses such as onsite water demand during gas production, livestock/irrigation water, stream-flow augmentation, habitat enhancement, industrial, and drinking water augmentation.
- Produced Water Quantities - Under this task, water quantity data will be collected and analyzed. While some data is available from published studies, additional information will be collected from producers (e.g., wellhead flows and pressures, clustering, etc.). The information will be broken down into basin, resource (i.e., CBM, gas shale), gas/water ratios, current disposal/use strategies, means of transportation/conveyance, and the maximum brine volume/flowrate/percent of feed that will be economically acceptable to the industry for re-injection.
- Current and Emerging Technologies for Produced Water Treatment - Currently, ion exchange (IX) resins as well as reverse osmosis (RO) and nanofiltration (NF) membranes represent the most commonly employed desalination technologies for produced water. However, electrodialysis and/or electrodialysis reversal (ED/EDR) are also considered viable processes for water desalination.
Several key and detailed criteria used in the assessment of desalination technologies include: specific production efficiency, product water quality, infrastructure consideration and constraints, energy usage, life-cycle including capital and operational costs, operational and maintenance considerations, as well as pre- and post-treatment requirement. During this study, this knowledge database will be further updated with new research results. This subtask will summarize the recoveries, product qualities, brine qualities and quantities, energy needs, capital and O&M costs for various technologies to treat produced water and will highlight limitations and knowledge gaps.
- Beneficial Use Matrix - The water quality of treated produced water will be targeted towards the final beneficial use. A matrix detailing the quality of beneficial non-potable and potable uses will be generated. The matrix will allow the user to determine, given a known produced water quality, the necessary treated water quality based on end use and the quality of the generated treatment residuals.
- Industry Advisory Council Workshop - CSM has assembled an Industry Advisory Council (IAC) that will be engaged in the project through regular teleconferences and physical meetings. Findings of Tasks 4 and 7 will be presented during a workshop with the IAC after completion of these tasks to review the results and define the next phase of the study that is directed to investigate potentially viable treatment technologies at the laboratory scale.
Selection of Treatment Technologies for Produced Water (Task 5) –
Given the conditions under which produced water is generated, development of a treatment strategy requires special design considerations. Produced water is most often generated in remote locations where it is difficult or expensive to supply a large quantity of chemicals and dispose of treatment residuals. Equipment maintenance and downtime are important criteria because it may be inconvenient to get personnel on-site for routine maintenance or equipment repair. Treatment technologies must be easy to operate because skilled water treatment operators will likely not be available at produced water sites. Therefore, processes for treatment of produced water must be robust, reliable, durable, redundant, economic, capable of achieving high water recovery, and should operate relatively autonomously with low maintenance and minimal consumables.
Produced water is generated at individual well sites with limited life-spans. Technologies to treat produced water should also be mobile (to accommodate use at multiple sites over time), modular (to manage changing water quantities at a specific location), and flexible (to handle the variability in water quality between sites and within one site as the well matures). Modularity is particularly important for CBM produced water as more water is generated in the early stages of well development and water production rates may drop by as much as 1/3 per year.
There is consensus that a single process cannot achieve an ultimate treatment goal, especially for complex water compositions and particularly if high water recoveries are desired. Therefore, in order to take advantage of process synergies, to achieve higher recoveries, and to save cost, various potential technologies will be tested during this task and employed in hybrid configurations. Once potential treatment options have been identified for representative produced water types (as identified in Task 1), the treatment strategy considering pre-treatment, desalination, post-treatment, brine disposal, and brine management will be verified in the laboratory with bench- and laboratory-scale experiments. Potential pre-treatment, treatment, and post-treatment technologies will be evaluated in this study for their separation efficiency (rejection and recovery), robustness, and O&M cost in treatment of produced water having various water chemistries.
Project researchers will investigate commonly employed pre-treatment processes such as chemical flocculation followed by media filtration, cartridge filtration, microfiltration (MF), and ultrafiltration (UF), but will also investigate emerging technologies, such as ceramic UF membranes for representative produced water categories (see Task 4). For the representative produced water categories identified during Task 4, CSM and ANL will investigate the cost-effectiveness of conventional RO, NF, and electrodialysis reversal (EDR) treatment technologies. In addition, the team will investigate the viability of non membrane-based approaches in desalination such as capacitive deionization (CDI) and ion exchange (IX) technologies for these water quality categories. In collaboration with Eltron R&D, the team will also investigate novel NF and RO membranes such as fouling resistant membranes as well as membranes that were developed specifically to work with hot feed streams (many produced waters exhibit temperatures higher than 35°C).
After water treatment, two streams are generated, a purified water stream and a concentrated brine (residual) stream. For beneficial use, post-treatment might be required in order to meet discharge or beneficial use regulations. But more importantly, brines must be treated and properly handled to prevent environmental problems. Project researchers will investigate different brine treatment processes and management strategies to mitigate potential problems. These include advanced evaporation processes, novel membrane processes, and also solar ponds that might serve as a source of renewable energy.
Field Validation of Viable Treatment Processes for Produced Water (Task 6)-
Once viable processes have been verified in the laboratory, pilot-scale treatment trains will be designed, assembled, and tested at representative production sites for field-scale validation. This validation will occur at two to three sites representing different water compositions, made available by the industry partners. At a minimum, field trials will be conducted with sodium bicarbonate and sodium chloride type produced waters.
The goal of the proposed field testing is to evaluate potential technologies under real-world conditions in which feed water is introduced directly from the source, environmental and climate conditions are not constant, and the combined system is operated continuously for an extended time period. Data from the pilot testing will be analyzed to determine the effectiveness, robustness, and ease of operation of the treatment strategies. Preliminary cost estimates for the design of a full-scale facility will be developed following a successful pilot test.
Assessment of Management Options (Task 7)-
Besides technical issues related to treatment of produced water from unconventional gas exploration and production, there are multiple conditions that have to be fulfilled in order to establish beneficial use from a regulatory, political, environmental, economic or legal standpoint. To identify the most economic and environmentally appropriate solution, cost/benefit analyses will be performed. This task has two subtasks:
- Develop Draft Integrated Decision Framework - Evaluation of management options leading to beneficial use will require a structured decision process that identifies, evaluates and, where possible, quantifies the regulatory requirements, benefits, risks and costs of each option. This subtask will develop a draft Integrated Decision Framework to help producers and end-use partners conduct cost-benefit analyses and assess management options. The Framework will provide a starting point for discussions with a broad group of gas industry, water industry, regulatory agency, tribal, agricultural, landowner, and environmental stakeholders.
- Stakeholder Workshops - A total of three stakeholder workshops will be conducted to solicit key information, refine and confirm the decision framework, establish evaluation criteria, share treatment technology research results, and develop incentive-based beneficial use approaches.
- Workshop No. 1: The goal of the first workshop will be to introduce the objectives of the project, educate participants on the diverse interests and perspectives of stakeholders, review the draft Integrated Decision Framework, establish evaluation criteria and weighting factors, update on beneficial use opportunities and constraints, and conduct an initial “fatal flaw” analysis of management options. The outcomes of this workshop will be a second draft of the Integrated Decision Framework, a summary of critical success factors and fatal flaws, and a list of data gaps to be addressed.
- Workshop No. 2: The goal of the second workshop will be to integrate the findings of the treatment technology feasibility and cost analysis (Tasks 4 and 5) into the Integrated Decision Framework. Between the first and second workshops, concept-level unit costs for treatment, conveyance, storage, and residuals management necessary to achieve various beneficial uses will be developed.
In addition to costs, the workshop will explore approaches to “monetizing” the full range of benefits that will accrue (environmental and societal as well as economic) through life-cycle analysis resulting in a cost-benefit model. Recognizing the water/energy/carbon nexus, the model will provide a guideline for estimating the net increase or decrease of greenhouse gas emissions from a particular management option. As these costs and benefits will be very site-specific they will be presented and discussed as examples for application in the Integrated Decision Framework.
The workshop attendees will use this cost-benefit model to quantify economic drivers and identify threshold values for project viability. The outcomes of this workshop will be to disseminate information on feasibility and cost of treatment options and to review and confirm cost models to be used in the Integrated Decision Framework.
- Workshop No. 3: The goal of the third workshop will be to integrate the information gathered from the technology assessments, field validation, and the two previous workshops to finalize the Integrated Decision Framework. The workshop will focus on linking incentives with various beneficial use scenarios. Financial, regulatory, political, environmental, and legal aspects of produced water beneficial use incentives will be discussed.
Emphasis will be placed on scenarios that have an economic driver and can achieve multiple stakeholder objectives. The outcomes of this workshop will form the basis for the guidelines to be prepared under Task 8.
Development and Validation of Guidelines (Task 8)-
Findings and results from the workshops will form the basis for development of guidelines for publication. This task has two subtasks:
- Development of Guidelines for Management of Produced Water Leading to Beneficial Use - This subtask will document the findings of this study and compile guidelines to foster beneficial and sustainable use of produced water. The guidelines will incorporate the Integrated Decision Framework with a technically sound, objective basis for identifying and quantifying the benefits and costs of various management options. The objective of the Guidelines is to provide a practical, adaptable and robust tool that CBM and gas shale operators can use to identify the most appropriate treatment technologies, benefits, costs and beneficiaries of produced water management alternatives.
- Case Studies - Case studies will be selected to illustrate application of the Integrated Decision Framework and will represent a range of project conditions, water qualities, and beneficial uses. The case studies will provide practical information on “lessons learned” and illustrate the decision process for selection of the most appropriate beneficial uses and the most cost-effective treatment and residuals management technologies. Case studies will document capital and O&M costs and, where applicable, any revenue streams derived from beneficial use. In addition, environmental and societal benefits will be documented. It is anticipated that two case studies will be presented in the final report.
Project Start: September 12, 2008
Project End: March 11, 2011
DOE Contribution: $1,560,393
Performer Contributions: $2,456,692
RPSEA – Kent Perry (firstname.lastname@example.org or 847-768-0961)
NETL – Virginia Weyland (Virginia.Weyland@netl.doe.gov or 281-494-2517)
CSM – Jörg E. Drewes (email@example.com or 303-273-3405)
Final Project Report [PDF-3.74MB]
Project website - http://aqwatec.mines.edu/produced_water/index.htm [external site]
Technical Assessment of Produced Water Treatment Technologies [PDF-3.25MB] - Project Report - July, 2010