Treatment and recycling Archives - TETRA Technologies, Inc

Oil Recovery from Produced Water

Posted on May 29, 2024October 10, 2024 by Yannick Harvey

The Challenges of Residual Oil

Practically all produced water contains varying levels of residual oil depending on the reservoir and the specific parameters of the operation. This residual oil poses a number of challenges for recycling and reusing the water for subsequent fracking operations.

First, produced water intended for recycling and reuse must be aggregated in large storage facilities such as pits, above-ground storage tanks, or frac tanks where the suspended oil will separate naturally. The permitting for such storage, however, does not account for the appreciable volumes of oil that can accumulate, leading to regulatory compliance infractions.

Second, the maintenance of these storage facilities—specifically, removing the oil and sludge—is labor-intensive, time-consuming, and expensive.

Third, accumulated oils in storage facilities give off flammable flumes that pose health, safety, and environmental hazards. In some cases, these hazards can even warrant shutting down wellsite operations, a situation that isn’t going to earn any blue ribbons for cashflow.

Fourth, if the residual oil is not removed from the produced water in a timely fashion, the recycling regimen may require additional treatment to achieve adequate quality, such as the addition of an excessive amount of oxidizer.

Oil Recovery Before Water Treatment

As with the timeless expression “When life gives you lemons, make lemonade,” the residual oil in produced water is not an absolute negative. In fact, the operators of commercial saltwater disposal wells consider the ‘skim oil’ an integral revenue stream. So, if you intend to recycle produced water, removing the residual oil well ahead of storage is not only a necessity, it’s also an economic benefit.

To do that, engineers at TETRA conceived and developed the Oil Recovery After Production Technology (ORAPT). The separation system accumulates and removes native residual oil, undesired light constituents, and oil slugs (due to unplanned bypasses) from produced water in real time. The system is designed to facilitate efficient water treatment and compliance with regulatory storage requirements. With the captured oil then diverted to a nearby tank, the water storage remains clean.

TETRA ORAPT unit set image. — A mobile, standalone TETRA ORAPT unit set up at a pad site.

The Nuts, Bolts, and Numbers

The ORAPT system works by providing a wide spot in the produced-water line to allow gravity to induce oil separation. The produced water stream is funneled into the main section of a tank where its velocity is reduced, thereby enabling the suspended oil to float to the surface. When the flow reaches the opposite end of the tank, a series of weirs allows the water to be pumped out to the water management system while the oil is diverted to a separate tank.

How efficient is the ORAPT? An absolute efficiency metric is difficult to obtain due to the huge variance in produced water composition from one formation to the next, as well as the different specifications of each job. That said, when operated within its design parameters the technology generally provides an efficiency in the range of 90+% with only trace amounts of oil remaining at 50–100 ppm. Nominal throughput of the system is up to 28,000 barrels of fluid per day.

Among the system features are:

automated operation;
self-contained water and oil pump skid for simplified deployment;
self-contained discharge pumps for chemical injection;
automated tank-level management, trending, and alarms;
and automated emergency bypass and shutdown available per operational requirements.

Case Study

In South Texas, the TETRA ORAPT was deployed in the Eagle Ford Shale Play in tandem with the TETRA SwiftWater Automated Treatment (SWAT) system after a major operator had approached TETRA seeking a means to recycle the high volumes of produced water and flowback from an unconventional pad site. At the time, disposal of the site’s wastewater required 50 truck loads per day traveling to and from the remote job site. For the operator, disposal of such high volumes of wastewater was simply not an attractive, long-term solution from an environmental and economic perspective.

One of the challenges with the job was achieving the high standards of water quality set out by the Texas Railroad Commission (TRRC), which regulates the oil and gas industry in the state.

After four months of operation, the SWAT system had recycled 221,360 barrels of water—achieving TRRC standards—and the ORAPT system captured approximately 700 barrels of oil. Additionally, the operation reduced offsite disposal loads from 50 trucks per day to just one.

The operator has been very pleased with the results and plans to continue the recycling and oil recovery operation for at least a full year with subsequent jobs planned.

Solving the Water Woes in Oil and Gas Operations

Posted on March 25, 2022April 23, 2024 by Jon Malone | Strategic Accounts Director

One of the biggest challenges confronting the oil and gas industry is water management, especially in unconventional operations. Hydraulic fracturing requires a lot of clean water, and for every one barrel-of-oil-equivalent, a typical operation now yields anywhere from four to ten barrels of produced water—that is water native to the reservoir itself, which is too briny for use in fracking. Ironically compounding this challenge of overabundance is the water scarcity endemic to core regions like the Permian Basin and, more generally, the entire western half of the United States. In fact, water scarcity is now considered a global problem, with water increasingly characterized as a commodity.

Recycling, ESG, and Seismicity

To meet this challenge, the most impactful innovation is recycling the produced water and flowback, carefully treating and blending it for optimal use in frac operations. Recycling is the smart choice not only because ESG—environmental, social, and governance—concerns have emerged as a major priority across every industry, but also because recycling the water is now the more cost-efficient route compared to disposing of it. Recycling reduces freshwater use, lessens roadway truck traffic to deliver freshwater and remove wastewater, and virtually eliminates disposal of wastewater in saltwater disposal (SWD) wells.

A number of factors are coalescing to make disposal of produced water less attractive: water scarcity, environmental concerns, the cost and logistics of moving millions of gallons of water, and the growing concern over seismicity associated with injecting wastewater into SWD wells.

Seismicity has, of course, been a concern among regulatory agencies in the Mid-Continent region for a few years. Now the issue is spiking in the Permian Basin, which accounts for 60% of produced-water volumes in the United States.[*] Late last year, both the Texas Railroad Commission (RRC) and the New Mexico Oil Conservation Division (OCD) signaled they’re taking the issue very seriously. New Mexico updated its regulatory framework and Texas established two seismic response areas (SRAs) to limit injection capacity and permitting in Midland, Ector, Martin, Culberson, and Reeves counties. These developments will likely entice more operators to turn to recycling.

Factors in Water Management

TETRA is at the forefront of water management in oil and gas production and completion applications, offering the full spectrum of solutions—everything from sourcing clean water to the treatment and recycling of produced water and flowback, as well as the filtration, storage, blending, distribution, and transfer. The Company engages decades-long core competencies in chemicals, chemistry, and advanced R&D to develop water treatments that are compatible with the reservoir, which is absolutely paramount for successful stimulation and the life of the well.

For most operations, the main challenges of recycling produced water are the brininess, the high volumes, and the transfer. Produced water contains a lot of salts and other minerals, so it has to be treated in a specialized way to render it fit for use in fracking. And the treatment program needs to be able to handle high volumes of fluid so as not to be a bottleneck and hinder production from the well. Our SwiftWater Automated Treatment (SWAT^™) system, for example, enables recycling in excess of 100,000 barrels of produced water per day using unique technologies and processes that render the water optimal for frac use.

Water transfer is another challenge, one that really brings home the importance of planning and the holistic aspect of a good water management program. On this front, TETRA has the resources to not only provide the industry’s only double-jacketed and quickly deployable lay-flat hose, but also to coordinate access and distribution of water-transfer. Surveying the scattered dispersion of pad sites and storage ponds, TETRA can help operators identify and connect to the most strategically located sources of water, which makes their operations more efficient, economical, and environmental.

Designing for the Optimal

Regarding the design of a water management solution, a comprehensive, holistic approach is best. Instead of sourcing one component from Company X and another from Company Z, partnering with one company, like TETRA, ensures all of the technologies are compatible and overall performance is more efficient, reliable, and economical.

Another feature to further enhance operations is automation. Adding it to remotely monitor and control pumping, treatment, storage, transfer, and blending greatly enhances efficiency and economics and provides visibility and transparency throughout water management activities. Automation reduces the number of personnel needed onsite, as well as their travel to and from the site in vehicles. Our automation solution—BlueLinx^™ automated control system—can also apply algorithms to optimize the efficiency of engine pumps to reduce fuel consumption and emissions. Automation also lessens the risk associated with human error and having more workers onsite.

The Market and Long-Term Vision

Given the continued and even rising demand for fossil-fuels, water management is certainly here to stay. As stimulation techniques continue to evolve and steadily enhance to yield more hydrocarbons, we can expect the volumes of water to go up as well. Right now the U.S. water-management market is valued at $12 billion and growing fast, with a compound annual growth rate of 10% expected through 2028. This year recycled produced water will account for 40–42% of the demand for frac-water, up from 39% in 2021 and projected to be 45% in 2024.

Eventually, we want to be able to treat produced water so that it’s suitable for use in other industrial applications, agriculture, and livestock sustenance. Another target is large-scale recovery and commercialization of useful minerals. With our core competency in aqueous chemistry and expertise in extracting minerals and manufacturing products from them, TETRA is ideally suited to pursue these goals, which are realistic and obtainable, not just castles in the air. It’s an age-old cliché but it’s true: invention really is the mother of invention. Water is an absolute necessity, and should be considered a commodity—not traded on any commodity exchange, but nonetheless utterly invaluable to sustain us.

[*] All industry metrics come from Rystad Energy.

Safeguarding Your Frac-Water With TETRA Water Storage Management

Posted on May 17, 2021February 3, 2025 by Matt Cappers | Director of Operations for Water Treatment

Water Treatment: The (Very) Early Years

With the advent of hydraulic fracturing, the storage, treatment, and maintenance of large volumes of water have steadily evolved into a major component of jobsite operations. Frac-water is typically stored in either above-ground tanks or, more commonly, in-ground ponds (or water pits) outfitted with liners. There is, however, a challenge to storing large volumes of water.

Ancient civilizations figured out centuries ago that water stored for the long term becomes unsuitable for human use, though they knew nothing about the science of water-borne pathogens. In fact, wine is likely the first water treatment invented by humans. In the ancient civilizations of the Mediterranean Region, water for consumption was typically cut with wine because its alcohol level (slightly above the 10–14% of modern wines) was almost precisely at the point that kills bacteria, thus rendering the water safe.

Bacteria: Not Just a Potable Water Problem

Like potable water, frac-water also must be properly treated to prevent bacterial growth. With the ability to proliferate at a rapid pace, bacteria will reduce sulfates in the water, thereby creating hazardous hydrogen sulfide (H₂S) gas as well as iron sulfide solids. The latter can severely damage the porosity of a reservoir and consequently diminish production if pumped into a well.

The Necessity of Water Storage Management

Despite the potential for bacterial growth, properly managing frac-water storage ponds is an often-undervalued component of operations. In truth, proper pond management is a sound preventative measure that requires minimal investment and typically entails treating the water with a biocide, aeration, and a chemical to promote solids separation. Neglecting pond management will invariably lead to costlier remediation down the road.

The TETRA Water Storage Management Guidelines

Water Treatment

The first step of pond management is water treatment, which begins with determining the levels of dissolved oxygen (DO), oxidation-reduction potential (ORP), and adenosine triphosphate (ATP), an organic compound that fuels the growth of living cells like bacteria. An initial shock treatment of sodium hypochlorite (bleach) is then applied, which is typically 12.5% by volume but will vary depending on the level of ATP. Next, a long-term treatment with dimethyl dialkyl ammonium chloride (DDAC) provides additional disinfection as well as solids separation. Each treatment should also be accompanied by aeration to thoroughly mix the water and chemical additives. If a pond lacks an aeration system, a transfer pump can be used to ‘roll’ the water.

Weekly Maintenance

Each week, a technician should record the pond’s level, temperature, and appearance, as well as collect samples from four equidistant points along the perimeter. Common descriptors of appearance include clear, milky white, opaque white, tinted green, tinted brown, and black. The weekly log should also note whether the pond has been aerated (or ‘rolled’) at or around the time of sample collection.

Analysis of Water Samples

Water samples should be analyzed each week to determine the DO and ORP levels. If ORP drops below 50 millivolts, then the sample should be further analyzed to determine the ATP level. Otherwise, samples for ATP analysis can be collected every two weeks instead of each week. If the ATP level exceeds 10,000 picograms per milliliter, a 30-parts-per-million (ppm) dosage of 80% active DDAC should be applied to maintain water quality.

Pond Aeration

The most effective means of aerating a large pond is to use a subsurface aeration system to introduce diffused air directly into the water. Unlike surface aerators and fountains, subsurface aeration creates the most air-to-water contact, circulation, and mixing, and causes the least evaporation. As noted above, if the pond lacks an aeration system, then a transfer pump may be used to ‘roll’ the pond, but this is not ideal.

Aeration is typically conducted once or twice every 24 hours, depending on the water temperature and local weather conditions. Warmer climates may require running the aeration system continuously, but caution should be exercised here because too much air can cause the pond to become turbid. TETRA recommends maintaining a minimal DO level of 2–4 ppm to prevent bacterial growth; higher levels are preferrable if they can be maintained.