Using a closed-loop, integrated, automated water-management solution

In today’s market, with oil prices hovering around half their predownturn levels, the debt from years of funding a production boom coming due and operators shifting from production growth to profit growth, investors and company leaders are taking a more cautious approach and, crucially, weighing the impact of their company’s investments and capital expenditures on their sustainability objectives. From a business perspective, sustainability entails a variety of environmental, social and governance concerns. These include
• the health and safety of a company’s workforce
• its relationships with key stakeholders, such as, investors, regulatory agencies, customers, suppliers, insurers, employees and the public
• cost-conscious allocations of resources
• structuring organizations and operations to be more resilient to market volatility

Alongside these, the public is increasingly assessing the oil and gas industry on environmental and social sustainability issues.

Fortunately, for those of us in the water-management business, the oil and gas industry has reached an auspicious tipping point. Recycling produced water is not only effective in terms of cost and fluid quality, it’s sustainable and recognized as such among a growing number of operators.

Three primary factors got us here:
• the large volumes of produced water coming out of the ground
• the challenges of saltwater disposal (SWD) wells
• and pivotal technological advancements in water treatment, system integration and automation

That Ocean Down There ... It’s Coming Up
As we know, unconventional basin operations are yielding massive amounts of produced water. Super-efficient completion techniques come at a price—along with more hydrocarbons comes more water—anywhere from four to 10 barrels for every one barrel of oil. That’s a lot of produced water.

At the Shale Water Expo in Houston last year, one expert characterized unconventional production as “essentially bringing the Permian Sea to the surface.”

In fact, produced water is the single largest waste stream in oil and gas production. The huge volumes would be less of a problem if all that water could immediately be used for hydraulic fracturing (or irrigation), but it can’t.

Produced water contains salts, organic materials, metals and other impurities that render it unsuitable for completions (or irrigation). So, historically, SWD wells have been the final destination of most produced water.

SWDs Aren’t A Sustainable Solution
In North America, the limited number of SWD wells are filling up fast and are now faulted for causing increased seismicity. With studies showing that injected water can radiate a good distance from an injection well, induced seismicity is complicating regulatory oversight and permitting, and, to put it charitably, does little to improve the industry’s reputation in the eyes of the public. In terms of logistics, SWD wells don’t simply go where operations go. They can be many miles from a pad site, which means the water has to be transported to the disposal well, usually by truck.

Moving millions of gallons of water by truck requires hundreds of trips— which drive up costs, necessitate timeconsuming logistics, increase road congestion and air emissions, and have zero appeal for local communities.

By any measure, SWD wells alone are not a sustainable solution for produced water. They will undoubtedly remain one avenue for disposal, but the operational conditions that vary from basin to basin demand a toolkit with alternatives.

Technological Advancement: From Piecemeal to Integrated
One of the most sustainable alternatives is recycling produced water. In fact, recycling is a model of sustainability, not just for the environmental benefit, but also for long-term costeffectiveness and operational efficiency—due in large measure to advancements in treatment and blending and how the various steps are integrated in a closed-loop system.

Recycling produced water is not new, but over the past decade or so, the technology has been applied mostly in piecemeal fashion, using discrete components in an inefficient manner. The reasons behind this approach are simple enough.

First, the industry has historically been slow to adopt technologies outside the scope of the simple extraction of hydrocarbons from rock.

Second, until recently most people in the oil field had doubts about recycling technology—whether it would actually yield usable water.

And third, those making financial decisions weren’t sure that a water-recycling system would be cost-effective or that the investment would yield a profitable return. As a result, they approved only cautionary use of discrete components here and there.

Today, however, innovation has enabled the industry to surmount these obstacles. Comprehensive watermanagement systems—especially those that are automated with components that are seamlessly integrated, instead of discrete and marginally compatible—are not only the sustainable solution, they can, in fact, transform produced water into a fluid optimal for fracturing, and they are now cost effective. In other words, water recycling is a practical, sound investment.

Most of us will readily agree that recycling is one of the most sustainable approaches, but why automation and integration? Here’s why. Discrete, manually operated components can work, but seldom in a cost-effective, efficient way.

Assuming one clears the compatibility hurdle, which can be a challenge if the equipment comes from different suppliers, manual technologies require a number of people at the work site, checking levels, turning valves, adjusting chemistry, changing filters and emptying sand traps. The more people on-site, the higher the labor costs and the greater the safety risks.

The Building Blocks of Sustainability
What does an automated, integrated water recycling solution look like? Let’s start with the basics. A closedloop system, like the TETRA Lowest Cost-Per-Barrel Water Management Solution, will provide greater simplicity and control over water treatment and recycling, blending, distribution, storage, transfer and sand management.

Engineered for compatibility, the system components will
• remove virtually all sand from the produced water
• pretreat the water and recover residual hydrocarbons (which can be routed to the sales pipeline)
• chemically treat the produced water to exact specifications
• eliminate bacteria and sulfides using EPA-approved biocides
• blend diverse types of water to ensure consistent fluid quality
• control storage and distribution to ensure a steady supply of frac fluid

What’s key here is that the overall process is holistic, all the steps are interconnected. This maximizes efficiency and quality assurance and minimizes health, safety and environment (HSE) risk to personnel and landowners.

spwm cherednichenko2Automation Elevates Operations
Now, let’s add automation to this closed-loop water-management system, like the TETRA BlueLinx™ automated control system. We do this by outfitting all the water-management components with sensors, from the static hardware—flowlines, valves, tanks—to the dynamic devices—the pumps, hydrocyclones, pretreatment and treatment systems, the blending manifold and distribution manifold.

The sensors are connected to programmable logic controllers (PLCs), which process sensor data and adjust the system components according to the desired, pre-set parameters, all in real time.

This automated, closed-loop system is singular and intelligent, not a motley collection of gadgets requiring constant manual adjustment. The components communicate with one another. They all work in concert to respond in real time to variation in things like inlet rates and water composition.

A sudden spike in the volume of produced water flowing into the system, for example, is met with a corresponding increase in chemical treatment, thus ensuring the integrated system yields a properly treated fluid.

Likewise, if pump pressure suddenly drops because of a leak somewhere in the flowline, the system automatically turns off the affected pump and closes the appropriate valve, thereby minimizing what could otherwise be a costly spill.

The smart system also regulates pump speed for optimal performance, which reduces fuel consumption and wear on the pump engines. Using less fuel reduces refueling trips to the site and lowers emissions—another boon to sustainability.

A solution like the BlueLinx system can reduce the number of on-site workers to as few as two, which, of course, lowers labor costs and exposure to risk.

The lion’s share of task —opening and closing valves, checking tank levels, adjusting chemistry, emptying sand from hydrocyclones—are handled automatically.

But there’s more.

This automated, closed-loop system is singular and intelligent, not a motley collection of gadgets requiring constant manual adjustment.

spwm cherednichenko4Wellhead In The Cloud
While the automated, closed-loop system practically runs itself on-site, we need to be able to see what’s happening—without driving to the site and walking around it.

Remember those sensors on the equipment? They send their data not only to the on-site PLCs, but to the “cloud,” as well—the Big Data cloud. The water-management system is connected to the Internet of Things (IoT) via either cellular or satellite link. This enables remote monitoring and control from a distance.

Using a PC, smartphone or tablet, the user can log into the system and pull up an interface that displays digital twins of all the components— the pumps, tanks, valves, hydrocyclones, blender, distribution manifold, chemical-treatment equipment—any device with a sensor.

Now, an individual sitting in an office or truck far from the frac site—an operator’s service manager, a serviceprovider technician, a customer monitoring ongoing operations, anyone with access—can monitor the entire water-management operation.

The digital twins display metrics like pump pressure, tank levels, chloride ratios and sand-cyclone efficiency. If some parameter needs adjusting, then that can easily be done via the interface.

And while it might feel like playing a higher-stakes video game, the automated system actually reduces the stress of managing a multifaceted water-recycling operation.

spwm cherednichenko3Data Is Power
In addition to the enormous gains in control, efficiency and quality assurance that an automated, integrated system provides, there’s also the reporting.

With cloud computing comes the ability to generate detailed, customized reports on a host of metrics and ratios—pump-engine fuel consumption per day, the amount of sand removed for a given volume of water, the volume of water treated per hour, trends in pump pressure, trends in chemical composition and more.

Such reports can then be analyzed and provide invaluable data to enhance operations or design new installations at other sites. If knowledge is power (it is!), then accurate data can only enhance that power.

Ultimately, what we want to accomplish is to bring the highest degree of sustainability to fracturing operations. Simply put, the best way to do that is by recycling produced water to minimize or eliminate disposal, reduce freshwater sourcing, lessen environmental risk and impact, improve safety and, of course, extract hydrocarbons for the lowest cost per barrel. The best way to achieve these objectives is with a closed-loop, integrated, automated water-management solution. 

 

Authored by Natasha Cherednichenko, vice president for water and flowback services, TETRA Technologies