Solutions to preventing wildlife mortality in oil field waste pits are fairly simple
and straight forward and are being implementing by many oil operators. The U.S. Fish and
Wildlife Service suggests the following measures.
Use Closed Containment Systems
Closed containment systems require little or no maintenance and the system can be moved
to a new site when the well is shut in. Closed containment systems eliminate soil
contamination and remediation expense. Closed containment systems used to collect oil
field produced water do not attract wildlife and isolate oil from the environment.
Eliminate Pits or Keep Oil Off Open Pits or Ponds
A fail-safe solution is to remove the pits or keep oil from entering the pits.
Immediate clean up of oil spills into open pits is critical to prevent wildlife
Use Effective and Proven Wildlife Deterrents or Exclusionary Devices
Netting appears to be the most effective method of keeping birds from entering waste
Deterrents That DO NOT Work at Oil Pits
Flagging is ineffective at deterring migratory birds and other wildlife from oil field
- Strobe Lights
- Zon Guns
Published scientific studies as well as field inspections by U.S. Fish and Wildlife
Service personnel have documented bird mortalities at oil pits with flagging, reflectors,
and strobe lights. Although Zon guns or propane cannons have been used in other
applications to deter birds, their use in oil pits have been ineffective.
Effective Net Installation
The effectiveness of netting oil pits to exclude birds and other wildlife depends on
its installation. Effective installation requires a design allowing for snow-loading and
one that also prevents ground entry by small mammals and birds. According to a
professional net installation contractor, a maximum mesh size of 1 1/2 inches will allow
for snow-loading and will exclude most birds. Netting should be suspended a minimum of 4
to 5 feet from the surface of the pond to prevent the net from sagging into the
oil-covered pond during heavy snow-loads. Three-inch steel tubing can be used for support
posts and are set a maximum of 7 feet apart. These are buried a minimum of 7 feet in depth
and set in concrete. Three-inch steel tubing is also used as a top rail to connect the
posts. Cable is strung across this frame at 7-foot intervals along the y-axis and the
x-axis to form a grid of 7-foot squares by the cable. The netting is draped over this
cable grid. Netting should be wide enough to drape down the sides of the frame to prevent
ground entry by wildlife. A bottom perimeter cable strung along the bottom of the posts at
ground level is used to attach the bottom of the net. Cables are strung over the net at
7-foot intervals to prevent the wind from whipping the net back and forth. Proper
maintenance should be performed to repair holes in the netting and to re-stretch sagging
nets after heavy snow-loads.
Properly installed net at commercial oil field
produced water disposal facility in Wyoming. Net is supported
by steel frame and high-tensile strength cable to prevent
sagging. Sides are also netted to prevent ground entry by
birds and other wildlife. Netting to exclude migratory birds
should also extend down the sides of the supporting frame to
prevent ground entry by birds and other wildlife
This net was installed
less than 5 feet above the fluid surface. A heavy snow-load caused the net to sag into the
oil-covered pond. The exposed oil entrapped migratory birds. Netting should be suspended a
minimum of 4 to 5 feet from the surface of the pond to prevent the net from sagging into
the oil-covered pond during heavy snow-loads.
Poorly installed and
maintained netting at this commercial oil field produced water disposal facility in
Wyoming allows entry by migratory birds and other wildlife. To insure effectiveness,
netting should exclude wildlife from ground as well as aerial entry.
Proper maintenance is
necessary to prevent wildlife and migratory birds from entering oil-covered pits. Cottontail rabbits are shown in the photo both outside and insidethe netted pit area. The cottontail in the upper center of the photo has entered through this small opening on the side of the net
Mesh size is critical to prevent the entry of songbirds and small mammals. The large mesh shown in this photo will allow entry by songbirds and small mammals into the production skim pot.
In Summary . . .
- Netting has been found effective at deterring birds from oil pits.
- HDPE balls have been used as bird deterrents in waste pits.
- Use enclosed tanks to separate the oil from the produced water prior to discharge into
- Industry compliance with existing state and federal regulations prohibiting the
accumulation of oil in separator pits.
- Report migratory bird deaths in oil pits to the nearest U.S. Fish & Wildlife Service
|For more information, contact Pedro
Pete Ramirez, Jr. (Pedro_Ramirez@fws.gov)