The mechanical pump is a procedure almost continuous suction and transfer oil to the surface.
This method is essentially a subsurface pump reciprocating action, supplied with power supplied through a rod string. Power comes from an electric motor or internal combustion engines, which mobilizes a unit area through a system of gears and belts.
Conventional Mechanical Pumping has its main application in the global production of heavy and extra heavy crude, but is also used in the production of medium and light crudes.
Not recommended for deviated wells and is not recommended when the production of solid and / or gas ratio – liquid is very high, and that undermines the efficiency of the pump.
Components of a Mechanical Pump
2. Surface pumping equipment: Structure and swing, Motor, Gearbox.
3. Pipe or tubing
4. Rod string
5. Underground Pump
Engine Mechanical Pumping Unit
Motor function of the pump unit is to provide mechanical installation mechanical energy which is eventually transmitted to the pump and used to lift the fluid. The engine selected for installation must have sufficient output to lift the fluid at the desired rate from the level of working fluid in the well.
Rocker Oil Structure
This component is responsible for supporting the components of surface mechanical pumping system, is also responsible for transferring energy to the pumping well from the engine to the top of the rods, making the need to change the rotary motion of a motor reciprocating motion.
This device allows you to change gears through the angular speed by the engine delivered more torque sufficient to allow movement of the swing (as in the field of Unipetro ABC).
Polished rod – polished Varillon
The direct relationship between the rod string and surface equipment is Varillon polished or polished stem. Polished stems are available in three sizes, the size for any facility depends on the size of tubing and rod diameter suction at the top of the rod string.
Other components of the surface of Mechanical Pumping
Near the upper end of the polished Varillon Varillon this a clamp which is supported by bar loader. The bar loader in turn is supported by flexible cables known as reins pass over the head of the rocker (horse head) until the end of swing (walking beam).
The rocker oil (walking beam) is supported near the center of gravity by a structure called the post master (Sampson Post), the walking movement is transmitted to the fiddle bem (Pitman) and this in turn is driven by the crack.
The distance between the crack and the union of fiddle determines the length of the race Varillon.
Rocker function of Oil
The main function is to store energy in the downstroke, and deliver power on the upstroke.
Transmit power from the surface equipment to pump groundwater. The rods support the weight of the fluid in addition to its own weight.
The pump functions are:
* Receive the formation fluid from inside the production string.
* Raise the fluid to the surface.
Main components of the subsurface pump
* Barrel work
* Stading valve (valve stationary)
* Traveling valve (valve traveler)
Operation of an underground pump
The stationary valve allows the oil enters the cylinder of the pump. In the race to the bottom of the rods, the fixed valve closes and the traveling valve opens to pass oil pump to the pipeline. In the upstroke, the traveling valve closes to move to the surface the oil is in the pipeline and allows traveling valve between the pump oil. The constant repetition of movement up and down keeps the flow.
Effective stroke of the piston
The volume of oil handled during each stroke of the piston of the pump depends on the length of the polished rod stroke if the relative motion or the piston in the working barrel.
The strokes of the piston and rod grinding differ because the rods and the tubing is stretched, the piston overtravel due to acceleration. Fluid load is transmitted alternately as the stationary and traveling valve are opened and closed during the pumping cycle causing deformations in the rods and tubing.
In the downstroke the stationary valve is closed and the open traveler. In the upstroke the traveling valve closes and opens stationary.
Polished rod loads
Five factors contribute to the net charge of the polished rod:
* Load the fluid.
* Dead weight of sucker rods.
* Acceleration of the burden of the suction wand.
* Force floating on sucker rods submerged in the fluid.
* Forces of friction.
Displacement Pump Production Rate and Mechanical Pumping System
* Wells with gaseous or liquid foaming conditions often have a 25% to 50% efficiency.
* Gas wells with clear separation of forming gas in the gap would have 50% to 70%.
* For wells with good separation in the hole and extensive submergence of the pump, the efficiencies would be 70% to 80%.
* For wells with high fluid and gas with no interference, the volumetric efficiency can reach up to 100%.
Advantages and Disadvantages of Mechanical Pumping Oil
Advantages of System Mechanic Oil Pump
* Easy to operate and maintain
* You can easily switch production rate of change in pump speed or stroke.
* You can pump the well at a very low inlet pressure for maximum production.
* Usually the most efficient form of artificial lift.
* You can easily exchange area units.
* You can use gas engines as primary movers where electricity is not available.
* You can use the pump off control to minimize fluid load, electricity costs and rod failures.
* Can be monitored remotely with a supervisory control system pump.
* You can use modern computers dynamometer testing to optimize the system.
Disadvantages of Mechanical Pumping System Oil
* It is problematic in wells with high deviation.
* Can not be used in offshore wells by large surface equipment and production capacity is limited compared with other methods.
* You can not operate with excessive sand production.
* The volumetric efficiency drops dramatically when you have free gas.
* The rate of production falls with depth compared with other artificial lift
* It is unobtrusive in urban areas.