Oil and gas production and disposal tanks have a high susceptibility to lightning and static damage. The following suggestions make up a short list of best practices for tank batteries and well pads.
Use 3/4″ x 10 foot copper clad ground rods, minimum of 2 per site, always at opposite ends of battery. Each ground should measure 25 Ohms or less. Additional grounds can be placed at the back side of tanks.
Use tinned copper class 1 lightning protection conductor and tinned copper UL 96 rated materials throughout the lightning and static protection system.
Run a continuous trunk line of tinned copper class 1 lightning conductor from a ground (near the first step of the catwalk stairs) to another ground past all the tanks at the opposite side of the battery. This trunk line is to be secured to the underside of the stairs and along the catwalk or piping with clamps spaced no more than 36″ apart. This trunk line will be used to provide at least two paths to ground for each tank.
The lid and flange of every thief hatch must be bonded together with a UL listed tinned copper bonding strap. Every thief hatch, isolated metal body, catwalk, etc, must be bonded to the grounding system so the battery will rise and fall in electrical potential evenly.
Remove bound charge in fiberglass tanks with a Static Lasso® tank protector and bond to the tinned copper class 1 lightning conductor and grounding system.
Streamer Prevention Terminals (Dissipators) shall be installed on the tanks and catwalk handrails at spacing no more than 15 foot apart. Dissipators mounted on PVC piping will need to be bonded back to the grounding system with class 1 tinned lightning conductor.
Dissipators should also be mounted on all tall structures inside the pad or nearby a tank battery such as separators, heater treaters, or light poles.
The grounding for all electrical equipment should be bonded to the lightning protection grounding system for the tank battery. Separate grounding systems are potential risk for personnel and arcing of static charge.
Make sure that all the panels, variable frequency drives, PLC’s and ESP’s are installed with appropriate Type I Surge Protection Device of at least 120kA per phase surge current rating.
Truck load out stations need to have a static bonding cable installed to ensure that electrical potential between the truck and the tank battery are equalized before fluid transfer begins.