Stuffing Box Wellhead Containments
Stuffing Box Containment
There are many different types of stuffing box wellhead containments on the market in the USA, Canada, and throughout the world.
There are a lot of reasons why Oil Companies around the world use secondary wellhead containment on sucker rod pumping units also know as beam pumps.
The largest reason to use a containment is over all cost savings. These cost savings can be broken down into several quantifiable margins, all resulting in lower lift costs for oil producers.
Environmental spills cost oil companies hundreds of thousands of dollars a year, with wellhead containment on the stuffing box, producers can reduce the over all environmental footprint of pumping units while reducing the down time caused by spills and leaks.
What is a “Stuffing Box”?
A Stuffing box can come in many sizes, shapes, pressure ratings and most importantly with various sealing arrangements. The primary function of a stuffing box is to seal fluid pressure while the polish rod is stroked by the pumping unit. This stroking motion is to function the bottom hole pump causing oil to rise to the surface. Most stuffing box packing also know as sealing arrangements last from days to a couple years this is all dependent on the production environment. The application can change during the yearly seasonal temperature changes or over the life of the production. All the of these different variables changes the outcome of how long packings (seals) will last before a leak or spill occurs.
Why use containment?
With the use of most secondary containment, when a packing leak occurs, the pumping unit will shut down, stop the polish rod from stroking as this stops most of the flow of produced fluids, preventing large environmental spills. Further to the environmental aspects, containments reduce operator and or pumpers service time at each well during any clean up scenario. Some containments offer better containment hygiene than others. Aside from keeping oil in the flow line containments allow producers to run leaner during times of lower oil prices, the containment allows for less visits which give service companies the ability to cover more wells. Lastly some brands of Stuffing box containment offer lubrication injection which provide added life to all stuffing box packing, this again reduced time between down time reducing the lift cost of oil production.
What does a typical stuffing box containment look like?
Most wellhead containments work on all sizes of polished rods and all makes of stuffing boxes, some alterations are needed for best practises.
Stuffing box containments come in varies styles and sizes, legacy designs are typically 2 pieces design which have a gasket allowing the box to be split and installed without disrupting the pumping unit. These legacy brands typically have a plastic or cast-iron base with a plastic shroud around the top of the stuffing box – There are positive value and negative value in every design
The newest models of containments are one-piece design which is installed over the polish rod while the pumping unit is stopped or in service. Some new designs include a rain guard which stops rain from filling up the containment which will artificially stop the pumping unit. Lastly other new designs have incorporated a lubrication system providing the greatest value in one complete unit.
Pumpers have different names for a wellhead containment. For example: enviro boxes, pollution controllers, stuffing Box containments, bathtubs and more.
How does stuffing box containment stop the oil?
Some of the wellhead containments functions are different than others, some wellhead containments are strictly that, they contain the product from leaking on the ground. This is done by shutting down the pumping unit once the oil level gets to a certain maximum level. This happens by a float mechanism that acts like that of a float system of a toilet. Once the level reaches the set point, which is set by the pumper, it shuts down the pumping unit stopping the flow of fluid.
The switch for the wellhead containment has different names. They are commonly called: shut off switch, kill switch, float, high level wellhead containment switch, sensor switch made by many manufacturers.
Another type of switch for the wellhead containment is the Vega Switch. It is a sensor switch that looks like a tuning fork, and when the switch senses product touching the switch it will shut down the pumping unit. Each unit will screw on to the side externally of the wellhead containment and will be wired with the pumping unit.