Jet pump

Jet pump

1. TITLE: JET PUMP By: Tejas Vanbhane 18MS063

2. History The Italian inventor Secondo Campini showed the first functioning man-made pump-jet engine in Venice in 1931. However, he never applied for a patent, and since the device suffered from material problems resulting in a short life-span, it never became a commercial product. The first person to achieve that was New Zealand inventor Sir William Hamilton in 1955.

3. The Jet Pump Jet pumps, also known as ejector pumps, are devices capable of handling and transporting all forms of motive fluid including gas, steam, or liquid. They can be considered mixers or circulators, since the intake combines multiple fluid sources. Multiple inlets are used to draw in a constant stream of fluid, using pressure to create lift through suction. The primary drawback is efficiency: both frictional losses and unavoidable mixing losses are incurred. Nevertheless, careful design can produce pumps with efficiencies on the order of 30—40%. The combination of intake pressure and velocity of the liquid or gas jets the media up from a well, tank, or pit through the pump to the discharge point. Compressible-flow pumps, for example, steam-jet ejectors, employ converging-diverging nozzles for full expansion of the jet. Figure 1

4. Working Principle The jet pump artificial lift system is composed of two principal parts: the surface pumping equipment and the downhole jet pump. In the surface, the reciprocating pump transfers energy to the fluid increases its pressure, drove through surface piping, production tubing (or annular space) until the jet pump, placed on the bottom. Surface Equipment consists of the power unit (high-pressure pump with accessories, motor, gear reducer, controller), power fluid conditioning unit (VCU) and high-pressure lines. The following figure gives an example of a typical jet pump surface equipment configuration:

5. Working Principle When the power fluid travels at high pressure through the smaller area of the jet pump, known as “nozzle“, the Venturi effect occurs increasing the speed and reducing the pressure. This generates the suction of reservoir fluids in the space between the nozzle and the throat. When the power fluid gets into the mixing tube the flow area increases, reversing the energy transformation, reducing speed, and increasing the pressure. This allows the reservoir fluids to be lifted to the surface through the annular space. The nozzle and throat are the key components of a jet pump. The ratio of the areas of these two parts is known as the area ratio of the pump and it determines the performance characteristics of the pump. Pumps with the same area ratio have the same performance and efficiency curves

6. Construction Jet pumps are EJECTORS that use a jet of steam to entrain air, water, or other fluid, and EDUCTORS that use a flow of water to entrain and thereby pump water. The basic principles of operation of these two devices are identical. The basic principle of operation of a simple jet pump of the ejector type is shown in figure 2. Steam under pressure enters the chamber through pipe A, which is fitted with a nozzle, B. As the steam flows through the nozzle, the velocity of the steam is increased. The fluid in the chamber at point F, in front of the nozzle, is driven out of the pump through the discharge line by the force of the steam jet. The size of the discharge line increases gradually beyond the chamber to decrease the velocity of the discharge and thereby transform some of the velocity head into pressure head.

7. Construction As the steam jet forces some of the fluid from the chamber into the discharge line, pressure in the chamber is lowered and the pressure on the surface of the supply fluid forces fluid up through the inlet, D, into the chamber and out through the discharge line. Thus the pumping action is established. Figure 2

8. Types And Uses There are four main types of jet pumps, which vary based on application and size: Deep well jet pumps are used in high volume applications, such as oil wells, which range from 800-15,000 feet in depth. The ejectors in these pumps are put down the well. Shallow well pumps are used in applications where the media is close to the surface, such as residential wells. The ejectors in these pumps are bolted to the nose of the pump. Convertible jet pumps are "convertible", meaning they can be set up to be used for either deep or shallow well applications. Miniature jet pumps are used for smaller (typically commercial) applications, such as aquariums.

9. Advantages No moving parts or mechanical parts that wear. Long run life. Providing that erosion is not a major problem, then a working life of at least four years is not unreasonable. Capable of high production rates. Adjustable to varying production rates by adjusting the power fluid injection rate. Low maintenance costs and are easily and quickly retrieved and replaced when maintenance is required. The ability to operate for extended periods of time without the need for intervention. Suitable for low gravity, high pour point crude oils or for controlling paraffin by using reverse circulation with hot water for the power fluid. Chemicals can also be entrained in the power fluid as needed. High tolerance to corrosive fluids by the use of CRA materials and/or inhibitors entrained in the power fluid. High tolerance to abrasives in the produced fluid. Suitable for remote operations. Multiple jet pumped wells can be powered by a central surface pump package.

10. Disadvantages Lower efficiencies than other forms of artificial lift resulting in higher horsepower requirements for the power fluid pump (typically the injection rates must be increased due to compensate for the working pressure limits of the system such as the wellhead). Power fluid injection rates are typically twice the production rate. Space limitations, especially for offshore installations The higher injection rates for the power fluid sometimes result in a higher surface facility investment for handling the volume of fluids returning from the well. Backpressure has a pronounced effect on surface injection pressure requirements that varies from approximately 1-1/2 to 1 to approximately 4-1/2 to 1 depending on the area ratio being used. High-Pressure Surface Lines. A jet pump cannot “pump-off” a well. A submergence of approximately 10%, based on the TVD of the location of the jet pump, may be required in order to prevent the problem known as “power fluid cavitation”, which occurs due to the decline in pump-intake-pressure as the well is “pumped-off” A tubing subsurface safety valve is typically employed in any well able to naturally flow to the surface. On some wells, there is also an annular subsurface safety valve. Since there is communication across the jet pump (annulus to tubing and vice versa), then any such safety devices need to be set below the pump in the well. Given that the jet pump is typically set as low (deep) as possible in the well, this creates problems for effective subsurface safety valve deployment.

11. Recent Enhancements Black Warrior Basin Application The Coleman Pump Company initiated a jet pump design specific to the production needs of a Black Warrior Basin coalbed methane well. This design utilizes a free pump type installation which is the most significant feature in the coalbed application. The design permits circulation of the pump to bottom through the power fluid string and allows the pump to be reversed back to the surface for repair or sizing. The downhole pump is run in three separate components: (1) the bottom hole assembly, (2) the pump housing, and (3) the pump (or throat and nozzle portion). Source: http://j-jtech.com/innovative-jet-pump-design-proves-beneficial-coalbed-methane-de-watering-applications/