Oilfield pits of all types and sizes require proper lining to retain their wastewater loads. It’s a common misconception that small pits, or those only used for certain types of wastewater, can go without liners at all. However, almost all pits, ditches, basins, and trenches need lining to protect the environment from damage. Even if federal and state regulations don’t require it, lining is a good idea to prevent the following risks.
Direct Hydrocarbon Contamination
The biggest concern for oilfield pit leaks is direct hydrocarbon contact for the surrounding soil and water. While it’s most common for leaked wastewater and residues to reach surface water supplies, it’s also possible for it to reach groundwater if there are large fissures in the rock layer. This can contaminate local drinking water supplies or even affect the freshwater supply for the surrounding oilfields. When hydrocarbons are mixed into soil and water, the compounds have a serious negative effect on microbial life. This effect cascades up, negatively impacting other forms of life as well. The consequences can last for years or even decades, and remediation is costly. It’s far easier to prevent contamination in the first place, with proper liner use.
Heavy Metal Accumulation
Aside from the hydrocarbons found in drilling wastewater, mud, and process water, there are also high levels of heavy metals in many drilling residues. This can be from compounds used in synthetic drilling fluids or from natural deposits of metals and minerals that are tapped during the process. Drilling residues can even include radioactive elements from certain minerals commonly found in oilfields. All these compounds naturally settle to the very bottom of the sludge layer of a pit or pond, making them prone to mingling with exposed soil and mixing into groundwater. A secure, flexible liner stops this issue and keeps heavy metals where they can’t migrate or escape.
Sludge Accretion
When there’s no clear and accessible liner to delineate the layer where the sludge is accumulating, it’s hard to properly dredge the pit without risking a leak. Dredging unlined or clay-lined ponds always runs the risk of a new leak since the removal of sediment can also disturb the settled base of the pit. Laying down a liner creates a clear barrier to signal when the pit has been emptied and is clean of sludge again for another cycle. If the oilfield has a high production level and is dredging on a monthly basis, it’s nearly impossible to keep up with that schedule without the help of lined pits.
Human and Animal Impact
If the pits are left exposed to the elements or lack proper lining, it’s too easy for humans and animals to accidentally slip into the water and become injured or die. Pits without flexible liners that run well over the edges will be prone to bank collapses that can drop workers into the wastewater so thick it’s hard to escape. Animals have an even harder time getting free of a quicksand-like mixture, especially deeper in the reserve pit. An appropriate, reinforced liner, prevents muskrats and other animals from burrowing into the sides of the pit and releasing torrents of wastewater. Don’t forget about fencing and netting to protect the surface water from unauthorized access as well.
Bank Collapse
Bank collapse is one of the biggest workplace hazards involving open pits in the field. Since these pits are often built close together and with only relatively thin banks and roads between them, it’s not uncommon for vehicles and heavy equipment to destabilize the soil and cause a bank collapse. The cost of retrieving damaged equipment and repairing collapsed banks can quickly outweigh any savings offered by trying to avoid liners. Using a high-quality, reinforced liner, in particular, is one step of the process in securing the banks. Lowering the slope to the natural angle of repose for the soil is also necessary, and a reinforcement grid may also be needed under the impermeable liner layer.
Lost Profit
Finally, don’t underestimate the direct costs of leaking oilfield pits and basins if they’re designed to hold process water and sludge that’s still being treated. Many operations either generate extra profits or substantial cost savings by reusing wastewater and skimming off valuable leftover oil. If these efforts are reduced or interrupted by the loss of water due to a lack of lining, there’s a potential for profit loss that equals the cost of the liner. Consider the extra price of the liner as a necessary expense for optimizing the reuse and reclamation of drilling wastewater.
Don’t let poor quality liners, or a lack of lining altogether, ruin the use of the pits on your oilfield. Make the reserve pits and other in-ground structures as easy as possible with the help of BTL Liners products. Our reinforced RPE liners are ideal for use on all types of ponds and pits used across the oilfield.
