Water Management at EOG
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EOG recognizes the importance of responsibly managing and conserving water resources in the communities where it operates. That is why EOG is taking steps to minimize overall water usage and address potential environmental impacts of the water used or produced during its operations.

How Is Water Used in an Oil or Natural Gas Well?

Water is an essential component in the development of energy resources throughout the world, including coal, nuclear, biofuels, crude oil and natural gas. It is both a required resource necessary for the drilling and completion of oil and natural gas wells and a byproduct of the production process.

Water is used in the drilling process to help cool the drill bit as it breaks the rock and carries rock cuttings out of the borehole to the surface.

After drilling, the target formation may be stimulated with hydraulic fracturing. A mixture composed primarily of water and sand, with a small percentage of special purpose chemical additives (which is highly diluted – typically less than 0.5 percent by volume) is pumped at a calculated rate and pressure through the borehole into the crude oil or natural gas-bearing rock formation. This creates carefully designed millimeter-wide cracks or fractures in the target formation. The newly created fractures are propped open by the sand grains, which allows the natural gas or crude oil to flow from tight (low permeability) rock formations into the well bore. Typically, the hydraulic fracturing of a horizontal well in unconventional shale formations may range from 24,000 to 120,000 barrels of water per well.

While the sand grains used in hydraulic fracturing remain underground in the rock formation to hold open the fractures, a significant percentage of the water and additives flow back through the well during the initial days of production. This is known as “flowback water.” Other non-potable groundwater that is naturally present in oil and gas formations flows through the well during the production of oil and gas and is known as “formation water” or “produced water.” The flowback and produced water is either recycled and reused or properly and safely disposed of through permitted and regulated facilities in accordance with federal and state laws and regulations.

In order to stabilize the well bore and protect groundwater and fresh water aquifers during drilling, completion and production operations, state regulatory authorities for many years have implemented and enforced strict requirements on how all oil and natural gas wells should be constructed. Each well bore must be encased in steel casing, called surface casing, and must be surrounded by cement to create a redundant safeguard for fresh water aquifers. Each state establishes casing and cementing specifications and determines the depth of the required surface casing to provide a secure barrier between the wellbore and any fresh water aquifers. EOG complies with and often exceeds state regulatory requirements by conducting additional monitoring and testing to confirm the integrity of surface casing and cementing programs.

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How Does This Compare to Other Uses of Water?

The water used in oil and natural gas operations is significantly less than the water used for the production of many other energy resources and other industrial, agricultural, recreational and municipal purposes. According to the United States Department of Energy and the United States Geological Survey, oil and natural gas operations use a small amount of the nation’s water resources compared to other societal uses.

While there are regional differences, water used for oil and natural gas operations typically represents less than 1 to 5 percent of total water usage. By way of comparison, in the 20-county Barnett Shale area of Texas, municipal uses unrelated to oil and gas operations account for more than 80 percent of water use. Power generation, irrigation and livestock are also significant users of water resources in this region. In the Marcellus Shale area of the Appalachian Basin, electric power generation accounts for more than 70 percent of water consumption. Other industrial and municipal uses unrelated to oil and gas operations are also significant in this region.

By way of example, the 120,000 barrels of water typically needed to drill and fracture a deep shale gas well is equivalent to the amount of water consumed by:

  • New York City in approximately seven minutes,
  • A 1,000 megawatt coal-fired power plant in 12 hours,
  • A golf course in Palm Springs in 5 days, or
  • A 7.5 acre field of corn in one season.

The Groundwater Protection Council has estimated that 300 million gallons of water are used to produce a single day’s supply of newsprint. While these examples represent continuing consumption, the water used for a crude oil or natural gas well is a one-time use. To provide further perspective, every seven seconds the Susquehanna River in the vicinity of the Marcellus Shale deposits 2 million gallons of water into Chesapeake Bay.

In comparing the amount of water used to drill and complete a typical shale natural gas well to other sources of energy, the amount of water used for the natural gas well equates to about 0.8 to 1.7 gallons for every million British thermal unit (MMBTU). One MMBTU equals about 1,000 cubic feet of natural gas. To put this in perspective, this is less than 20 percent of the water needed to produce one MMBTU of coal that is ready to burn in an electric power generation plant or less than 0.1 percent of the water needed to produce the same energy equivalent of ethanol for fuel.

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Water Issues are Different in Each Geographic Region

Each geographic region has unique needs and challenges when it comes to identifying sources of water, the ability to reuse or recycle water and methods for water disposal. Some areas have an abundance of water sources but limited disposal facilities. In other areas, climate and geographic conditions and the utilization of water for irrigation, electric power generation, industrial uses, and commercial and residential purposes results in greater competition for the sourcing and utilization of water.

As state and regional authorities and water management districts take these needs, challenges and differences into account in regulating water sourcing, usage and disposal, EOG takes steps to meet or exceed all regulatory requirements. In those instances where regulations restrict the reuse or recycling of flowback or produced water or treated industrial or municipal wastewater or the use of newer technologies in water treatment, EOG has worked with regulatory authorities to promote water conservation and efficiencies.

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What Sources of Water Are Used by EOG?

EOG uses various sources of water depending on the region where the drilling takes place. The sources of water include private and public ponds, lakes, rivers and creeks, potable and non-potable groundwater and the reuse of flowback and produced water. The company continues to evaluate the use of discharge water from industrial or city wastewater treatment plants. Throughout its operations, EOG attempts to minimize the use of water from sources that are also utilized for public drinking water. For example, in a number of regions of the United States, EOG is using non-potable water from aquifers not suitable for public drinking water. The availability of these aquifers differs from region to region.

While the water used for oil and natural gas operations is significantly less than the water used for the production of many other energy resources and other industrial, agricultural, recreational and municipal purposes, EOG recognizes the importance of responsibly managing and conserving water resources in the communities where it operates.

EOG management has formed a special project team, with representatives from each of EOG’s U.S. and Canadian operating areas, to accelerate our pursuit of best practices in water management. This project includes the full life cycle of water used in operations from acquisition through transportation, storage, treatment, flow back and reuse or disposal. The initial focus of the team has been to determine water quality needs, water source options and reuse options.

EOG is working with multiple technology companies to develop water purification technologies that can accommodate high volumes of flowback and produced water. EOG is also conducting test projects using other technologies designed to clean water for reuse. Each geographic area in North America has different challenges relating to geology, the amount of chlorides and other minerals and impurities in the water, as well as available infrastructure, and, therefore, different technologies may be required in different regions.

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EOG’s Water Management Activities in the Marcellus Shale

In the Pennsylvania Marcellus Shale, EOG has implemented several practices that exceed regulatory requirements in the use, handling and disposal of water and additives used in hydraulic fracturing and the completion process.

All completion fluid and flowback/formation water is stored in lined tanks. Special protective liners are placed on the well pad under the lined storage tanks and under the area where trucks deliver the fluids. Additional containment barriers are placed around the circumference of each well pad.

During multi-well completions, all flowback water is filtered, rebalanced and reused. As part of this process, particulates are filtered from the water, and the flowback water is tested to determine appropriate quantities of additives and dilution before reuse. This practice not only avoids the overloading of the water disposal infrastructure but minimizes the amount of fresh water that is required from other permitted sources. During periods when there are no completion operations, flowback and formation water is disposed of in properly permitted and regulated injection wells located out-of-state.

In Pennsylvania and throughout North America, EOG does not dispose of any flowback water in Publicly Owned Treatment Works (POTW) or commercial water disposal sites that discharge treated water into any surface streams, rivers or waterways. Only properly permitted disposal injection wells operated either by EOG or reputable third parties are utilized to inject water into deep geologic formations. All injection wells used by EOG are regulated by the U.S. Environmental Protection Agency or by state agencies pursuant to EPA regulations.

In Pennsylvania, EOG uses various sources of water and has taken steps to minimize the use of public water supplies. For example, EOG has partnered with the Blue Valley Acid Mine Drainage (AMD) Treatment Plant and Fish Culture Station in Brockway, Pennsylvania, which treats AMD water from a former coal mining operation near Brandy Camp Creek and utilizes the treated water in its operation of a fish hatchery. EOG utilizes some of the treated water for its Pennsylvania operations, and EOG’s financial support allowed the plant to continue operations when their state grants ran out. Enough money has also been generated to continue to operate the fish hatchery at the site and feed the fish. In 2009 the hatchery raised and released over 200,000 trout into local streams. This is a win-win scenario because EOG’s financial support is keeping the plant in operation and assisting the non-profit organization that manages it to achieve its goal of improving stream quality and habitat.

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EOG’s Water Management Activities in the Texas Eagle Ford

Where feasible, EOG’s Eagle Ford operations use non-potable water from aquifers that are not suitable for public drinking water. The availability of these aquifers differs from region to region in the Eagle Ford. EOG is also minimizing the use of surface water and is researching the purchase of municipal wastewater where available in areas near its Eagle Ford operations.

Methods are also being developed to reduce the amount of water used during the hydraulic fracturing process. Since the inception of operations in the Eagle Ford Shale, EOG has improved the efficiency of operations and has reduced water usage by up to 30 percent based on general estimates. The company understands the importance of South Texas water resources, especially during a drought, and has taken multiple steps to minimize the impact of its water usage.

In an effort to promote best practices by operators throughout the Eagle Ford and maintain open lines of communication with everyone involved and impacted by Eagle Ford Shale activities, EOG accepted an appointment to the Eagle Ford Task Force by Texas Railroad Commissioner David Porter. The Task Force is comprised of local community leaders, local elected officials, water representatives, environmental groups, oil and gas producers, pipeline companies, oil services companies (including a hydraulic fracturing company, a trucking company and a water resources management company), landowners, mineral owners and royalty owners. In announcing the formation of this Task Force, Commissioner Porter stated:

“The Eagle Ford Shale has the potential to be the single most significant economic development in our state’s history… and we must develop this shale responsibly, finding the proper way to develop these resources while ensuring environmental protection.”

EOG is also participating in the Eagle Ford Water Consortium in an effort to share best practices in the management of water resources with other significant Eagle Ford operators.

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EOG’s Water Management Activities in the Texas Barnett Shale

EOG is one of the founding members of the Barnett Shale Water Conservation and Management Committee. The committee’s members are committed to developing efficient and responsible best management practices for water used during drilling, completion and production operations for Barnett Shale wells in the Fort Worth Basin. These practices are inclusive of conservation, environmental protection and safe operations.

In certain areas of the Barnett Shale, EOG has utilized brackish water aquifers as source water for certain hydraulic fracturing operations. While naturally occurring brackish water is considered undesirable for human and livestock consumption, it is appropriate for use in the drilling and completion process.

Fresh water is also efficiently handled to avoid waste by installing a system of connected holding ponds lined with impermeable plastic.

EOG has also evaluated the following alternative methods for reusing water:

  • In-line filtration,
  • Centrifuge/chemical treatment and
  • Diluted produced water fracs.
After considering the technological challenges and the availability of regulated underground disposal facilities, it was ultimately determined that the safest and most economical way to handle the flowback and produced water in most areas of the Barnett Shale is to inject it into properly permitted disposal wells.

In addition to the use of permitted injection wells, EOG continues to consider alternative methods for reusing flowback water and ways to minimize the use of fresh water in its Barnett Shale operations.

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EOG’s Water Management Activities in Colorado

In Colorado, EOG is voluntarily participating in a groundwater quality sampling program launched last summer by the Colorado Department of Natural Resources and the Colorado Oil and Gas Association. As a result of the Colorado program, operators that drill new wells will collect groundwater samples both before and after drilling. The information is reported to the Colorado Oil and Gas Conservation Commission which will manage and publicize the data. This first-of-its-kind-in-the-nation program is designed to give neighbors added assurance that the oil and gas industry is taking necessary steps designed to protect groundwater in areas where drilling is taking place. The new program is considered a strong addition to Colorado’s existing groundwater monitoring program which has previously collected data on more than 5,000 wells drilled in the state. EOG is conducting water sampling in other operating areas if conditions warrant.

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EOG’s Water Management Activities in the Horn River and Other North American Basins

EOG is evaluating new processes for water treatment and filtration technology and discussing with regulatory agencies the use of new technology to allow the reuse of flowback and formation water in an effort to reduce freshwater requirements and reduce the need for water disposal. The goal is to identify technology that will allow the company to economically filter and treat large quantities of the water to the point of meeting freshwater standards.

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EOG’s Commitment

EOG is committed to actively managing and conserving water resources in the communities where it operates. EOG will continue to test new water purification and reuse technologies, take steps to minimize overall water usage in the drilling and completion of wells, meet or exceed permit requirements, properly dispose of flowback and produced water and otherwise address in a responsible manner the potential environmental and community impact of the water used, produced and disposed of during its operations.

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Sources:

Water use in the Barnett Shale (Texas Railroad Commission)

Prudent and Sustainable Water Management and Disposal Alternatives Applicable to Shale Gas Development, J. Daniel Arthur, P.E. (Presented to the Groundwater Protection Council, January 2009)

The Barnett Shale Water Conservation and Management Committee

Oil and Gas in Texas: A Joint Association Education Message (2010)

The Groundwater Protection Council

DOE Oil and Natural Gas Water Resources Program

Water Use in the United States (U.S. Geological Survey)

In the Know on H20 (Marcellus Shale Coalition)

Water-Thirsty Golf Courses Need to Go Green (NPR 2008)


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