Improve Water Monitoring Throughout the Lifecycle · of advanced automation (GPS World, July 16, 2013). Aqua-View™ services include hydrographic surveys using sonar and GPS real-time

32 Sha le P lay Wate r Managemen t | Ju l y / Augus t 2014

Improve Water Monitoring Throughout the Lifecycle of a Frac Well Part 2

BY JANICE HILLER AND AMY E. LOCKWOOD

Managing water supplies throughout the extraction process can be challenging given evolving regula-tions and increasing availability of innovative treat-

ment and monitoring technologies. Prior to the resource-extraction phase, you evaluated the quantity and quality of the

groundwater near the recovery site (see Part 1, May/June 2014). Now that you have completed pre-drill activities, ob-tained appropriate permits and constructed site infrastruc-ture, you are ready for the extraction process. From produc-tion through post-production phases, you will monitor water

Part 1 of this series focused on how to assess groundwater quantity and quality before hydraulic stimulation begins. This issue’s conclusion zeroes in on the production through post-production phases. For systems to operate properly, water must be monitored accurately and consistently, while addressing any changes to natural resources.

Sha le P lay Wate r Managemen t | Ju l y / Augus t 2014 33

“Currently, downtime costs can run as high as $50,000 per day

for drilling rig operations and up to $75,000 per day for

fracing,” said Luke Clausen, COO of DTC Energy Group Inc.

to ensure that systems are operating properly and address any changes to natural resources (Figure 1).

MANAGING FRESHWATER SUPPLIES

Depending on your permits, water can be sourced from sur-face water, groundwater, municipal supplies and recycled wastewater from previous fracturing processes. Each source must be managed and monitored to ensure adequate supplies for fracturing and for other permitted uses. Poorly managed water resources result in costly delays.

“Daily downtime drilling and completion costs depend largely on the operations taking place at various stages of the well. Currently, downtime costs can run as high as $50,000 per day for drilling rig operations and up to $75,000 per day for fracing,” said Luke Clausen, COO of DTC Energy Group Inc., an oilfield consulting firm.

Fresh water may be piped in, stored onsite or trucked in. If you rely on surface-water sources, continuous monitoring of seasonal river flows and reservoir levels leads to better plan-ning of withdrawals. Where water is stored onsite, frequent monitoring of storage volumes ensures that you can meet de-mand. Additionally, some operators check water temperature because cold water can fracture pipes or well casings.

Key water monitoring points at a resource extraction site: 1) source water characterization; 2) baseline groundwater quality sampling; 3) real-time level and chemistry monitoring of production water; 4) routine groundwater and surface-water quality sampling and reservoir pressure monitoring. Image courtesy of In-Situ Inc.

Figure 1

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Improve Water Monitoring

After completing water-storage surveys, different meth-ods can be used to calculate fluid volumes. Some operators develop a volumetric table for each pit. When the volume of water in an impoundment needs to be calculated, a manual measurement of water elevation is taken using a staff gauge. The number of barrels of water is determined by referring to the volumetric storage table. Manual tracking of impound-ment levels is time consuming and subject to inaccuracies.

Real-time data improves scheduling and forecasting, which ultimately saves time and money. To track water levels and temperature, a continuous monitoring and reporting sys-tem can be installed at each pit (Figure 2) or tank. Economi-cal solutions include a data-logging pressure transducer and telemetry system. The data logger records and transmits water level, water pressure and temperature data to a Web-based platform. Impoundment and tank volumes can be calculated manually or automated by using water-pressure data and volumetric conversion. To mitigate risks, the system sends alarm notifications if, for example, the high-water level mark is breached due to rain or a problem with water-pumping systems.

Select Energy Service’s AquaView™ System is an example of advanced automation (GPS World, July 16, 2013). Aqua-View™ services include hydrographic surveys using sonar and GPS real-time data. Pit water level data is transmitted wire-lessly and converted to volume. Operators receive accurate,

up-to-the-minute pit volume data on a computer or mobile device, which is critical to meeting completion schedules.

“This new technology is changing the way our industry does business,” said John Schmitz, Select Energy Services CEO in the GPS article. “AquaView will reduce downtime and assist in the maintenance of completion schedules, es-sentially removing the need from traditional water tracking and measurement systems.”

MONITORING WASTEWATER

Storage systems for wastewater streams (e.g., flowback or re-cycled water, other produced fluids) require attention to en-sure efficient operation and to comply with regulations. The EPA’s Office of Resource Conservation and Recovery (ORCR) reviewed state regulatory programs of oil and natural gas exploration, development and production (E&P) solid-waste management and identified common regulatory parameters. Table 1 on page 36, summarizes the EPA’s findings for top

Figure 2

Real-time data improves scheduling and forecasting, which ultimately saves time

and money.

A method for automating impoundment level monitoring. 1) high water level; 2) low water level; 3) silt/mud layer; 4) aluminum or plastic screen to keep mud/silt out of pipe; 5) instrument for monitoring water level, pressure and temperature and/or water chemistry; 6) stilling well-con-structed of PVC with holes along bottom length of pipe; 7) direct-read cable; and 8) telemetry system and/or optional controller/logger/local display. Image courtesy of In-Situ Inc.

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natural gas producing states. Regulations and requirements vary significantly and change rapidly, thus making it impor-tant to work with consultants who are well versed in the regu-latory landscape.

Permits provide details on surface storage and disposal, and on the technical requirements associated with the design, construction, operation, maintenance, closure and reclama-tion of surface pits, ponds, lagoons and tanks. Methods similar to those used for monitoring freshwater impoundments and tanks can be used to monitor:

• Storage-system fluid levels• Water quality of stored water• Leaks into groundwater and surface water supplies

Monitoring storage-system fluid levels

Many states have freeboard requirements for fluid levels in pits, impoundments and tanks. (See article State Level Water Storage Regulations—Not Level at All, January/February 2014 issue of Shale Play Water Management.) Freeboard is the dif-ference between the elevation of the crest of the embankment or tank and the elevation of the pool. A sudden drop in the water level can indicate a broken pipe or leak. A sudden in-crease in water level in the absence of a heavy rainfall may indicate a blocked decant or drain.

Similar to freshwater storage systems, manual or real-time methods are used to monitor fluid levels. To manually

check levels, operators can use a staff gauge. For example, if the elevation of the crest is 3,100 feet above sea level and the pool-elevation read on a staff gauge is 3,080 feet above sea level, then there is 20 feet of freeboard.

To automate fluid-level monitoring, the method described for assessing freshwater supplies can be used (Figure 2) and alarm notifications sent as an email or text message if the freeboard falls above or below a user-defined set point. Some operators prefer to see data at each storage unit. By installing an onsite controller with a local display, operators are able to quickly check fluid levels. An audible alarm or flashing light connected to the controller will notify operators if water levels exceed freeboard-level requirements.

Monitoring water quality of stored water

The geochemistry of flowback water varies and can impact how water is treated prior to disposal or reuse. Routine water-quality sampling or continuous monitoring ensures that flow-back water is ready for transport or reuse. The qualities and quantities of flowback and produced water will also help de-cide the amount of treatment required—from filtration to dilution to advanced treatment.

Spot sampling with a handheld instrument or test kit offers a quick, easy way to check water quality. Recent innovations take advantage of smartphone and wireless technologies so that mobile devices can be used to view and record data

Table 1

Summary of EPA’s findings for 13 of the top natural gas producing states



instead of proprietary meters. For real-time monitoring, install a water-quality instrument with a telemetry system or controller (Figure 2).

Many sites pay particular attention to total dissolved solids (TDS), salinity and total suspended solids (TSS). TDS and salinity can be derived from conductivity measurements. Conductivity sensors provide stable results and require mini-mal maintenance. To simultaneously ascertain water level and baseline water quality, look for a sensor that combines a pressure transducer with a conductivity sensor designed for high salinity fluids. TSS values are derived from turbidity measurements.

Detecting storage-system leaks

As energy companies increase water treatment and reuse onsite, they need to prevent leaks or seepage from storage systems and onsite recycling plants. Surface water and groundwater resources near a site require monitoring. For sites that must have a leak-detection system or that simply want to manage risks, manual and automated monitoring methods are available.

You can manually keep track of groundwater supplies by conducting routine sampling and water-level measurements at each monitoring well peripheral to a storage system. How-ever, periodic sampling doesn’t tell the whole story and can delay operations while waiting for lab results. A continuous monitoring system will keep stakeholders informed and speed up corrective action, if necessary. To automate, deploy water-quality and level sensors into monitoring wells, and connect them to telemetry systems for real-time status reports and alarm notifications.

A groundwater monitoring system can be set up around impoundments and tanks. Data from aquifer characterization tests and baseline groundwater quality tests collected prior

A low-flow groundwater sampling setup can include a multi-parameter handheld with smartphone interface, low-volume flow cell for fast throughput, water-level tape, turbidity meter and sampling pump.

Figure 3

Recent innovations take advan-tage of smartphone and wire-less technologies so that mobile devices can be used to view and record data instead of propri-etary meters.


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to site development will be required. Aquifer tests deter-mine hydrogeological properties that are used to approximate groundwater velocities and flow paths. The location of moni-toring wells in the leak-detection system will depend on each site’s hydrogeological characteristics. In general, wells will be installed up-gradient and down-gradient to the storage sys-tem. Monitoring wells may be installed in deeper aquifers to provide additional groundwater quality and level data.

Monitoring is critical to prevent violations of the federal Clean Water Act. For example, Pennsylvania state environ-mental inspectors found that XTO Energy Inc., a subsidiary of the Exxon Mobil Corp., had polluted water leaking from an open valve on a tank at the XTO water recycling plant in Penn Township, Pa. Authorities said chemically treated water was leaking into a tributary of the Susquehanna River basin. XTO Energy has agreed to pay a $100,000 fine and will spend ap-proximately $20 million improving wastewater management

near its fracking sites in Pennsylvania and West Virginia. As part of the settlement, XTO is now required to use real-time systems with alarm capabilities.

LONG-TERM MONITORING AFTER PRODUCTION

Ongoing environmental assessments may be required. They demonstrate your commitment to maintaining the site’s in-tegrity. Manual spot sampling, low-flow groundwater sam-pling and automated monitoring methods can be used to detect changes in groundwater or surface-water quality. Changes may indicate an accidental release of pollutants. A monitoring program reassures regulatory agencies and the public that hydraulic fracturing has not affected regional water quality.

Figure 4

Sealed monitoring wells track baseline reservoir pressure of targeted production intervals and subsequent pressure changes as production wells are pumped. The goal is to better understand the broader reservoir pressure regime in an area where resource extraction is occur-ring. A transducer placed in each well logs pressure changes at user-specified intervals and relays data through a telemetry system to those involved in the project. Photo courtesy of Landon Beck, Resource Hydrogeologic Services Inc.



Spot-checking water quality

Each state has its own requirements and specified methods for keeping tabs on groundwater and surface water quality after production. Multiparameter handheld instruments are used to simplify groundwater and surface-water spot sam-pling. However, periodic sampling only provides a snapshot of water quality. Natural variability may be misinterpreted as an event, and spot-checking requires travel time and sample collection. An automated system gathers data continuously so that you can observe changes in real-time and follow trends over many months.

Routine low-flow groundwater sampling provides defen-sible data and may be required by your permit (Figure 3, page 37). Previous Shale Play Water Management articles and Part 1 of this article (May/June 2014) discussed grab sampling and low-flow groundwater sampling.

Automating groundwater and surface-water monitoring

To facilitate long-term monitoring after production, a ground-water-monitoring system can be established similar to the one reported by the Greeley Tribune on Dec. 4, 2013. Colorado State University (CSU) launched the Colorado Water Watch demonstration program and is following groundwater chang-es in real-time. The project will involve test wells at a Noble Energy site throughout the Wattenberg Field in Colorado. Sensors are deployed into wells to monitor continuously. Data is transmitted to CSU with telemetry. If changes are detected, a team is sent to the site to collect samples for further analysis. The project aims to demonstrate the value of charting chang-es and promote transparency.

In addition to checking water quality, operators may be required to track baseline reservoir pressure and pump per-formance (Figure 4). Some sites are beginning to monitor surrogates (a parameter than replaces or acts as a substitute for another) for fracking fluid and methane. Surrogates are used to estimate concentrations of certain water-quality param-eters. Once a pollutant-surrogate relationship is established, the surrogate can be monitored with a real-time system.

Monitoring is critical to prevent violations of the federal Clean Water Act.

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Comparison of parameters and monitoring methods

Table 2

In some cases, if a municipal water supply is located down-stream, a continuous monitoring system is programmed to close the supply’s inlet if contaminants are detected. Water-monitoring instruments can be used with controllers or PLCs (programmable logic controllers) to close gates, pumps, inlets and other devices if an event occurs. An alarm system will im-mediately notify operators when a water intake valve closes. Then the water can be sampled and evaluated. This type of system is also used to monitor municipal supplies during shale gas production.

Table 2 summarizes key phases of a hydraulic fracturing

site lifecycle, the parameters that can be monitored and the methods used for monitoring.

SUMMARY

Water, once considered a waste stream in the conventional production of oil and gas, is redefined as a valued resource in today’s booming shale oil and gas market and must be man-aged throughout the extraction process. Considering this new paradigm, energy companies will benefit from the use of ad-vanced measurement tools and techniques developed for use



About the Authors:

Janice Hiller is the vertical marketing manager for In-Situ Inc. With nearly 20 years of downstream oil/gas and mining experience, she developed a strategy that promotes the use of industry-leading, geochemical sensor technology to reduce cleanup costs and accelerate site closures at oil/gas remediation sites. She is part of a team that is developing systems to aggregate and communicate remote site data in near real-time.

Amy E. Lockwood is a writer and marketing program manager for In-Situ Inc. She has more than 15 years of experience in the water-monitoring industry. She manages tactical execution of marketing communications projects for all of In-Situ Inc.’s vertical markets, including environmental monitoring. Ms. Lockwood has a B.S. in biology and an M.S. in technical communications from Colorado State University.

• Data-logging pressure transducers (water-level sensors)—Vented and non-vented options are available. To automate barometric pressure com-pensation, choose a vented system. Look for intuitive software and built-in communication protocols (e.g., RS485/RS232, 4-20 mA) for integra-tion into your data-collection platform.

• Water-quality instruments for downhole deploy-ment—Select instruments with low-maintenance sensors and the ability to integrate with telemetry, SCADA/PLC, controllers or other data-logging/collection platforms.

• Telemetry system with Web access and alarm capabilities—Economical cellular network systems are available with either long-lasting batteries or solar power.

• Controllers for use as a local display, data logger and control unit—Controllers can include audible alarm or flashing light, DC power for remote sites that lack line power and ability to integrate with water-level and water-quality instruments.

• Groundwater sampling equipment—Multiparam-eter water-quality instrument with intuitive software or smartphone interface that stores site photos and GPS coordinates, and automates report generation for quality-assurance programs and regulatory requirements. You will also need low-flow groundwater pumps, bailers and other sampling equipment.

Toolbox: Essential Equipment

in other industries, such as mining. Innovative monitoring systems improve regulatory compliance, optimize operations, reduce risks and improve production outcomes. In addition to gains in operational efficiencies, greater transparency through disclosure of information about the quality and dis-position of water resources to regulators, stakeholders and local communities can improve an operator’s financial perfor-mance, reputation and social license to operate.

REFERENCES

* See state regulations for details. Different ones apply to different types of disposal-storage systems. Source: Memorandum dated April 1, 2014, from Patrick M. Kelly, P.E., environmental engineer at ORCR

Photo 2 in Figure 1 courtesy of Luke Shannon, Senior Project Geologist

at Weston Solutions


Documents

Improve Water Monitoring Throughout the Lifecycle · of advanced automation (GPS World, July 16, 2013). Aqua-View™ services include hydrographic surveys using sonar and GPS real-time