Hydraulic fracturing sites often have half a dozen or more unique types of ponds and pits in order to manage the various risks around the property. Retention and fire prevention ponds around the edges may hold storm water at hand in case a fire breaks out, while other pits may only hold fresh water for pumping into the operating wells. Frac pits built for storing produced water and flowback experience far more challenges than these other water features. This is why you shouldn’t attempt to reuse existing water storage structures like wetlands or ponds with the hopes they’ll naturally hold water just as well. Frac pits require special care during the design stages to address all of the following challenges.
High Levels of Gas and Oil
All of the ponds and pits on a fracking site have a chance of being exposed to oil and gas due to a spill or release elsewhere. Even something as simple as a damaged vehicle can leak small amounts of oil or gas into a pond otherwise designed only for holding fresh water. In these cases, most liners should hold up just fine despite the exposure. Flowback water, fresh from an operation fracking well, is a different story. It’s rich with gas, grease, oil, and other forms of hydrocarbons, especially in the earliest stages of pumping. These hydrocarbons react badly with many polymers used for flexible liners because they’re also based on similar petroleum products. Materials like RPE can resist this degrading effect and stay intact even when exposed to the challenges of high levels of gas and oil.
Fracturing Sands and Abrasive Residues
Fracturing sands are a natural silica sand that just so happens to be very crush resistant. This is an essential feature, deep underground, where hydraulic pressure is used to crack open shale rock full of valuable oil and gas deposits. Unlike average beach sand, it contains a broader mix of minerals rather than primarily silica for greater strength. When it’s added to the hydraulic fluid pumped deep underground, it helps prop open tiny channels for the gas to flow out between pieces of broken rock. Frac sands are very round in granule shape, ensuring there’s space between particles for movement. These sands are less abrasive than they could be, but they’re mixed with more abrasive suspended solids in the form of broken bits of rock and dust. This means that fracturing sands in produced water are highly abrasive to liner materials used to seal frac pits. Ensure that all liner materials are reinforced to resist the abrasive effects of routinely adding new loads of fracturing sands and solids to the bottom and sides of the pit.
Risks of Exposure
The fluids stored in frac pits aren’t just potentially damaging to the environment, they also pose distinct human health risks. If the pit is designed without human safety in mind, it’s all too easy for someone to access the pond and fall in. Workers must be protected from unnecessary exposure as well, which is usually achieved with carefully staggered slopes on the banks to allow foot access to the surface without risking slips and falls. Low slope banks are also essential to allow anyone who does fall in to easily get out before experiencing long periods of exposure. Signage and proper lining are essential to prevent human exposure since many people may not know they’re moving around hazardous waste if they see the pit or pond from a distance.
All kinds of wildlife are attracted to these open bodies of water because they aren’t aware of the hazards of the liquids stored within. To a thirsty deer or a duck looking for somewhere to float, it just looks like another natural watering hole. Damage to wildlife attracted to the pits can cost far more in bad press for your company, or the industry as a whole, than in environmental fines. Putting in a few fences and nets can go a long way in keeping wildlife away from open frac pits, especially those used for long-term treatment and storage. Showing you’re making efforts to protect wildlife can offset any issues that do occur and are unavoidable.
Air Quality Issues
As the rich mixture of hydrocarbons, chemicals, and water slowly evaporates from the surface, a wide range of gases are released or produced in the process. When there’s little to no wind to clear the accumulation, air quality issues can threaten the productivity or safety of the site. Workers can’t safely move around the pits if dangerous gases accumulate just above the surface. Proper aeration and short-term water treatment solutions can prevent or solve these problems with relatively little effort. Considering evaporation rates during the design of the frac pit is also essential to controlling gas creation. Everything from the orientation to sun, wind exposure and the total surface area of each pond, has a huge effect on both evaporation speed and gas production.
While the Environmental Protection Agency (EPA) has passed the work of regulating oilfield frac pits and ponds to the individual states, this doesn’t change the chances of rapid changes in those laws. States are just as likely to suddenly enact new and stricter regulations regarding hazardous storage waste as the federal government, especially when public opinion shifts dramatically about oil and gas production. While some states in the past few years have loosened restrictions greatly on frac pits, this trend can also reverse at any time and leave hydraulic fracturing operators struggling to keep up. New regulations may apply to old pits, despite the operations having ended months or years ago. This means that lining a frac pit or pond better than the current regulations require, can pay off if you continue to meet new and more stringent environmental standards in the future.
Don’t let the challenges of frac pit lining interrupt the planning process or hold back the use of these valuable in-ground storage solutions. Simply choose liners capable of meeting these challenges and more by working with us here at BTL Liners. Our products, like ArmorPro, are designed with the needs of the oil and gas industry in mind. Whether you’re dealing with frac pits, holding ponds, retention areas, or secondary containment for drilling pads, our hydrocarbon resistant products can help.