A pumping unit is a piece of equipment used to extract petroleum products from a well in an oil field. Reciprocating piston pumps are commonly used for this purpose and many people associate the distinctive “nodding donkey,” as it is sometimes known, with the oil industry. Numerous companies manufacture pumping units, typically offering a range of designs and styles so people can select the model most suited to their uses.
While popular culture often depicts oil wells as “gushers,” shooting out columns of liquid petroleum for the taking, on actual oil fields, the process works somewhat differently. It is usually necessary to use a pump to bring the contents to the surface, as petroleum is highly viscous and moves sluggishly, and it often comes in very small pockets. A pumping unit is used to provide access, bringing up a steady supply of oil until a well runs dry and does not yield any more.
In the simple reciprocating piston pumping unit, the head of the device nods up and down, creating pressure inside the well to pull the oil up. Multiple units can be attached to a single well, and an oil field can feature hundreds of them, all working on individual areas to extract as much oil as possible. Companies developing oil fields must factor in the cost of installing and maintaining pumping units when they consider the expense of making the field usable. If deposits are limited, it may be too expensive to work the field successfully.
Personnel working in oil fields are responsible for periodically inspecting each pumping unit, checking for problems like leaks and failing components. They can temporarily stop production on a well to repair or replace a malfunctioning pumping unit, and units in need of repair may be sent to another site for servicing, depending on how the oil company is organized. This work also includes emergency shutdowns for fires and other emergencies where the oil field may become unsafe.
When selecting pumping units, people can choose between units of various heights and may select a variety of pump types. Some are designed for particular applications, such as use in oil fields where members of the public may protest if very tall, highly visible pumping units are deployed. Companies can also provide parts for their equipment and may offer support in some cases, with technicians specially trained in the installation and maintenance of their products.