Oil wells are the core of wellhead platforms, and oil well management is also the focus of platform operators' work. The common faults of electric submersible pump wells are as follows:

Underload

Possible causes of underload and corresponding handling measures:

Insufficient fluid supply to the formation. If the liquid supply to the formation is temporarily insufficient, the operating current of the electric pump will decrease, the oil pressure will decrease, the temperature will decrease, and the liquid production will also decrease. If the current is much higher than the set value of the underload current, the oil nozzle should be appropriately reduced to control the liquid production. When the oil pressure returns to normal, the oil nozzle should be gradually enlarged to the original scale for normal production. If the current is close to the underload value, the annular space should be immediately squeezed with water. When the oil pressure returns to normal, it should be stopped. During the water replenishment process, attention should be paid to the possibility of overload shutdown. If the long-term liquid supply of the formation is insufficient, measures such as acidification should be taken to remove pollutants from the reservoir and increase its permeability.

The sleeve pressure is too high. Due to high casing pressure, the liquid level drops, and when the liquid level approaches the suction port of the pump, it is easy to cause underload shutdown. At this point, the sleeve pressure should be slowly released and the changes in current should be closely observed.

Gas effects. According to the location of oil and gas separation, it can be divided into:

(1) Reservoir degassing. With the development of the oil field, the pressure of the formation gradually decreases, so the oil layer near the oil well begins to emerge

The current phenomenon of degassing is that if the degassing is slight, the gas gradually migrates towards the wellbore with the flow of liquid and formation pressure difference. During the migration process, the gas not only accumulates and expands, but also easily forms bubble flow and slug flow when it reaches the wellbore. In this case, the electric pump is prone to sudden underload. If the degassing is severe, it is easy for the oil layer to form gas resistance, causing the formation to be unable to supply liquid normally and stop production. When degassing occurs in the formation, measures such as water injection should be taken to pressurize the formation.

(2) Bottom hole degassing. When the production pressure difference is too large, the bottom hole flow pressure is too low, and at this time, it is easy to form bottom hole degassing. When degassing is slight,

The liquid flow in the wellbore is in the form of bubble flow, and the electric pump can produce normally at this time; When degassing is severe, the wellbore liquid flows in the form of slug flow, and the electric pump is prone to sudden underload. At this time, the production rate should be appropriately controlled to reduce the production pressure difference.

(3) Degassing at the suction port of the pump. During the production process, the pressure at the suction port of the pump is low, which can easily cause oil and gas

Separation, but the gas-oil ratio around the suction port of the pump is relatively stable. If the sinking degree of the pump is sufficient at this time and the effect of the oil gas separator is good, the electric pump can produce normally; If the sinking degree of the pump is not enough and the effectiveness of the oil gas separator is not good, the operating current of the electric pump fluctuates greatly, and the pump is prone to cavitation, which can lead to underload in severe cases. At this point, deepening the depth of the pump suspension can be adopted to increase the submergence of the pump, or controlling the output to increase the dynamic liquid level, or adding more stages of oil and gas separators to improve the effectiveness of oil and gas separation.

Air lock. Sometimes the gas cannot be taken out by the liquid after entering the pump body, so it gathers in the pump, forming Air lock phenomenon, leading to underload. The phenomenon before the shutdown was a decrease in oil pressure, with little change in current at the beginning, but later it decreased rapidly. Treatment method: Increase the back pressure of the pump, accelerate the fluid flow rate inside the pump, and carry out the gas inside the pump. Measures: Firstly, reduce the underload setting value, then reduce the pressure of the oil nozzle. When the oil pressure increases, quickly enlarge the oil nozzle and repeat this several times to observe whether it returns to normal. If the effect is not obvious, perform annular water squeezing and repeat the above operation until normal production is restored.

The viscosity of the well fluid is too high, and the pump suction port is blocked. This situation generally occurs in oil wells with severe emulsification and moderate water content underground

Around 30% -50%. Treatment method: Squeeze some hot water or diesel oil into the annulus appropriately to make the well fluid thinner, and also clean the suction port of the pump.

The water content of the well fluid increases. When the pump is in a stable state of production, some operating parameters of the electric pump are relatively stable,

If the water content of the well fluid increases, although the gravity of the mixed liquid column in the tubing increases, the pump efficiency increases, and friction and slip losses decrease, resulting in a decrease in the operating current of the pump, which may sometimes lead to underloading. Handling method: Reduce the underload setting appropriately.

The underload setting is too high. The underload value of a new unit is recommended by the manufacturer, but in actual production, it varies

Definitely suitable, if the underload setting value is too high, it can easily cause frequent underload shutdowns and cause significant damage to the unit. In this case, the underload value should be reset according to the actual situation.

The nozzle is holding pressure. For some oil wells, during the production process, it is easy to block the oil nozzle. When the oil pressure is too high, the current will

Descend to the under load setting and stop the machine. For such oil wells, inspections should be intensified and blockages should be promptly resolved.

overload

Possible causes of overload and corresponding handling measures:

The displacement of the pump suddenly increases. This situation usually occurs when the oil nozzle is slightly blocked, and when the oil pressure rises to a certain level or people

During the unblocking process, the oil nozzle suddenly burst open, causing a sudden increase in pump displacement and motor load, resulting in overload and shutdown due to the impact current. When encountering high oil pressure, the first step is to slightly move the oil nozzle and slowly release the pressure. When the oil pressure approaches the normal value, readjust it. Do not use excessive force to move the oil nozzle, as this can easily cause overload shutdown or fracture of the oil nozzle valve core. For oil wells that are prone to pressure suppression during normal times, inspections should be intensified.

Changes in well fluid. This situation generally occurs when the viscosity and specific gravity of the well fluid increase, or the well fluid contains too much mud and sand, and the motor

During operation, the load increases, leading to overload and shutdown. Treatment method: Properly control the displacement of the pump, reduce the load of the motor, and control the sand production of the oil well. Or replace the unit with a higher power for production.

Card pump. It is generally divided into the following situations:

(1) The well fluid contains a large amount of mud and sand, which blocks the rotation of the pump wheel and causes the motor to overload and stop. Processing method: If

If the pump is not severely stuck, a large displacement forward water squeezing method is used to backwash the pump chamber and remove sand blockage. If the pump is severely stuck, a well repair operation (sand flushing, pump replacement) needs to be carried out. After resuming production, production should be controlled to prevent sand production from happening again.

(2) During the well repair process, there may be foreign objects falling into the well (such as cable clamps falling off, rubber from the packer, etc.), but

During the production process, it is sucked into the pump again, causing the pump to become stuck, and the oil well cannot be produced normally. At this time, workover operations need to be carried out.

(3) For oil wells with relatively viscous well fluids and produced using low-power and small displacement electric pumps, when the well is shut down for a period of time

Afterwards, the well temperature drops, and the impeller and guide wheel of the pump are filled with this extremely viscous liquid, which is in a state of adhesion. When starting the well, the frictional resistance of the impeller is high, and the current is high, making it difficult to start the well. Treatment method: Before starting the well, first use a well killing pump to squeeze a little diesel oil into the oil pipe and soak it for a while, then use a mud pump to squeeze large displacement hot water into the oil pipe, clean the pump chamber, and then start the pump.

The process of squeezing water in the annulus. During the production process, when the oil pressure drops to a very low level and the current is close to the underload value, it is necessary to

When squeezing water in the annulus, attention should be paid to sudden overload and shutdown. The reason is that in this situation, there may be no liquid at the suction port of the pump, and the pump is almost in an idle state. When the annular space is squeezed with water, the pump suddenly sucks in liquid, the motor suddenly loads, and the surge current causes overload and shutdown.

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