Oil pumps are an extremely valuable resource in oil and gas production that help to transfer fluids to each point in the extraction process.
A great example of how oil is transported – a pump is used to transfer crude oil from the ground or from storage tanks directly into a pipeline. Another example of how pumps work in oil and gas extraction is through mud pumps that circulate drilling fluid (drilling mud) through the drill bit to maintain pressure and ensure drill bits do not clog.
What are Pump Jacks?
The majority of oil wells require the assistance of a pump jack, with the primary function to extract crude oil from oil wells. A large percentage of oil wells require the artificial lift of a pump jack to successfully extract and collect oil.
A pump jack uses an engine that is driven with electricity or gas in order to move a pivoting beam up and down. As the gear is driven up and down, a valve opens and fills as the arm of the pump jack lifts. After reaching the surface, any excess materials are separated from the crude oil to ensure a clean, pure product before the oil is transferred for processing.
The typical pump jack is able to average around twenty strokes per minute, with a range from 1 to 10 gallons of crude oil pumped with each stroke. The size of the pump jack also impacts the amount of crude oil extracted, with larger units extracting more crude oil per minute than smaller pump jacks.
Although every size of pump jack is suitable for extracting oil, not all jack sizes will work for every project. In fact, the depth of the oil in the ground, as well as the density of the oil pocket, is what determines the size of pump jack needed. Generally, the deeper the well, the larger the pump jack will need. The deeper and more dense jobs require more force in order to be extracted, meaning larger sizes of pump jacks are typically needed for these jobs.
Types of Oil Pumps
There are a few types of oil pumps used in the oil and gas industry. These pumps’ main purpose is to transfer different types of fluids. There are 6 main types of industrial pumps used in the extraction and transportation of oil and gas.
One of the most common types of pumps used in the industry are centrifugal pumps. They use centrifugal force for fluid intake of the pump, which then forces it to discharge via the force. Centrifugal pumps use rotation for power and force.
In addition, these pumps can be controlled through discharge flow control values. In practice, common types of centrifugal pumps are water injection pumps for secondary oil and gas recovery and horizontal multistage pumps used to ship crude oil.
Centrifugal pumps are mostly used to transfer low viscosity, or thin, fluids with high flow rates. This pump type is an important part of the larger pump network used in the extraction and transportation of oil and gas.
Gear pumps are another extremely common pump used for transporting fluids in the oil and gas industry. They work through a series of gears that pump fluid through positive displacement.
This pump type is often used for chemical transfer and high viscosity fluids. In addition, there are a few variations of gear pumps including external gear pumps and internal gear pumps. They are most often used for clean fluids. Like many other pump types, relief valves are necessary to prevent pressure buildup within the system.
External gear pumps use two spurs gears that control the internal set of gears. In this system, the internal gears do not touch, meaning that non-lubricating fluids can be pumped through the system. Internal gear pumps work by using a shaft driven gear to drive the internal gears. Both types of pumps use fixed displacement, which means that they pump the same amount of fluid for each rotation.
Reciprocating Plunger Pumps
Another common pump used in the industry are known as reciprocating plunger pumps. Plunger pumps can be found everywhere in the oil and gas production process.
As the name suggests, these pumps use a regular, routine, or reciprocating, motion of plungers and pistons to pressurize any fluid in the system. These pumps maintain a constant flow rate, no matter what the pressure is in the system.
One of the most essential parts of a plunger pump is the relief value that can discharge the pressure in the piping system. These pumps also require a lot of maintenance because of all of their moving parts and can be quite noisy.
Diaphragm pumps are probably the most versatile type of pump within the oil and gas industry. They are a type of positive displacement pump that is used to transfer fluid. These pumps work through changes in pressure and volume. The pump works through the principle of a decrease in volume causes an increase in pressure in the vacuum.
Diaphragm pumps are used to high-volume fluid transfer. They are most often used in oil refinery operations and require less maintenance than other positive displacement pumps. They have fewer moving parts and less friction during operation, resulting in the lower maintenance needs.
However, these pumps can be affected by low pressure inside of the system which, in turn, slows down the entire pumping operations. For this reason, they are not used in applications that require oil and gas to travel long distances or for continuous pumping operations.
Metering pumps are used to move very precise amount of liquid during the specific time period with an accurate flow rate. Metering pumps refer to the process and application of the pump rather than the actual pump type. In fact, most metering pumps are actually reciprocating pumps combined with a plunger or diaphragm at the end.
Progressive Cavity Pumps
You may also hear progressive cavity pumps referred to as eccentric screw pumps or just cavity pumps. These pumps are positive displacement pumps that is used to transfer fluid. They transfer fluids through the pump in a sequence of discrete cavities with a fixed shaped as the rotor is turned.
Applications for this pump type is for high viscosity, thick fluids and for fluids that should not be blended. They keep a constant, consistent flow no matter what the pressure is within the system. Like other types of pumps, a relief value is necessary to prevent pressure from building up within the system.