«Not always the cheapest is the most convenient»
«Not always the most expensive is the best solution»
Electrosumergible pumping has proven to be an artificial system of efficient and economical production. In the petroleum industry, compared with other artificial production systems has advantages and disadvantages, because for various reasons may not always be the best, well that is a candidate to produce artificially pumping electrosumergible must have characteristics that do not affect its operation relationships such as high gas / oil, high temperatures, the presence of sand in the produced fluids, which are factors with undesirable influences on the efficiency of the rig.
Among the features of the system are its ability to produce large amounts of fluid from different depths under a wide variety of conditions particularly well and is distinguished by the engine is directly coupled to the pump at the bottom of the well. The electric pump assembly works on a wide range of depths and volumes, their application is particularly successful when conditions are conducive to producing high volumes of liquids with low gas-oil ratio.
Description of pumping electrosumergible
A typical unit consists electrosumergible pump at the bottom of the pot for the following components: electric motor, protector, inlet section, electric submersible pumps and cable driver. The external parts are: head, cable surface. Control panel, transformer.
Key Components of a Pumping System electrosumergible:
2. Bomba (Stages, consisting of impeller and diffuser each)
4. Cable Restraint Suncho
5. Gas Separator
6. Section Sealant
7. Pressure Sensor Fund
8. Transformer (surface)
9. Variable Control
Team electrosumergible oil
Motor left) and pump (right)
Key features of a pumping system electrosumergible
It is necessary to bear in mind the conditions that tend to limit the use of this system:
1. It is not advisable to use this system in high regard GLR wells.
2. It is not advisable to use this system in wells under P. I. and low pressure.
3. It is essential for the design, knowing the bubble pressure of the reservoir will drain the well and the current pressure in the reservoir.
4. The importance of the latter is that it is not pumping a single phase (liquid) two-phase (gas + liquid), because the equation changes Productivity Index as the case, hence why it is necessary know the pressure of the reservoir and its value against its bubble pressure.
5. The mechanical conditions of the well may be another limiting factor so it is necessary to know the characteristics of the completion (diameter of the casing and the open intervals to production).
6. Another factor to consider is certainly the water cut, like most artificial lift systems, it is designed for incompressible fluids, and oil as we know it is understandable, even more so when accompanied by gas.
7. It must also consider the type of reservoir fluid and its characteristics (high viscosity of the fluid is a limiting factor, and in some cases, unconsolidated reservoirs, the fluids produced are accompanied by sand grains and in others are inlaid upon entering the facility, damaging parts)
Steps to design a pumping installation electrosumergible:
Collection of information from the well:
* Diameter, grade and weight of the liners.
* Perforated intervals.
* Estimated depth of the pump.
* Pressure: static and flowing to the midpoint of perforations.
* Bubble Pressure
* Estimated Regime
* Level Static
* Level Dynamic
Oil Specific Gravity
Water Specific Gravity
Additional considerations to take into account:
* Production of Fine
* Presence of Sales
* Presence of H2S
* High Temperature
Main equations that facilitate the design of an artificial lift system by pumping electrosumergible (BES)
Productivity Index equation (when the pressure is greater than the bubble pressure, flow of a single phase):
Productivity Index equation (when the pressure is less than the bubble pressure, or two-phase flow equation Vogel)
Qmax: Maximum flow at zero pressure
PWF: Background Fluent pressure (referring to the vertical midpoint of the perforations)
Pr: Pressure from the reservoir to a given flow
q: flow regime PWF pressure
The level (height) of the fluid dynamic pump is calculated considering the pressure from the pump location (usually 100 ‘over the top of the perforations), and finally the submergence of the reservoir pressure at that depth.
The total height is the sum of the heights (pressures) represented by the frictional pressure loss in the tubing and the discharge pressure and the dynamic height, according to the following equation:
Overall height (Ht = Heat). It is the sheepdog that the pump must overcome.
Hd: Height of discharge
Hs: Suction Head
Depth of Discharge. It is the algebraic sum of static discharge height and height due to friction losses in the system:
Hed: Height static discharge (pressure difference between the level of submergence and unloading, feet)
HFD: Height equivalent losses due to friction
Ps: discharge pressure in the separator (feet)
Suction Head. It is the algebraic sum of the static head plus friction losses in the suction of the pump:
Hes: Pump Vertical Depth (feet)
Hf: Height equivalent to the friction loss (0 feet)
Prs: Pressure from the reservoir to the depth of suction (ft)
To apply the equations is necessary first to determine the optimal value of q from the Vogel equation, the curve plotting the values of the regime (q) vs, dynamic height.
Once found the corresponding height value and the graph will pump performance is selected and the height and the corresponding power per stage, dividing the value of Ht between the height value found, you get the number of stages, then the latter value multiplied by the power (hp) is the total power of the engine brake.
Determination of Dynamic Level:
* Calculate the distance between the midpoint and the top of the holes (vertical)
* There is the algebraic sum of the level of submergence of the pump (1000 ‘) the pressure at the midpoint of the perforations and the distance from the pump at the same point (all in feet)
* Replaced the value found above and the other values in the equation and is the total charge flow regime selected.
The characteristic curves used in the pumping system electrosumergible are shown in the chart below: