4-电潜泵运行过程中所监测的参数

ESP Operating Parameters

ESP Operation Once an ESP system is commissioned, the operator plays a key role in the system’s performance and run life Key parameters must be monitored to insure proper operation of the system Failure to properly monitor or interpret these parameters can be costly

Operating ParametersThree basic ESP operating parameters are … Gross Production Rate Pump Intake Pressure Operating Motor CurrentBy monitoring these parameters, an Operator can better determine the relative condition of an ESP or anticipate possible problems

Flow Rate

Production RateBy monitoring the production rate an operator can … Determine the approximate operating point on the pump curve Trend the rate of declining production Look for possible pump wear, tubing leaks, etc.

Loss of production is usually the first indicator of a downhole problem with an ESP

Pump Intake PressureBy monitoring PIP, an Operator can ... Determine relative unit sizing accuracy by comparing with the computer sizing Anticipate unit cycling Look for tubing leak, pump plugging and/or wear

Increases or decreases in PIP can indicate a change in the pump performance, well inflow, or installation integrity

Motor CurrentBy monitoring motor current, an Operator can ... Look for trends in unit loading Spot possible motor damage due to electrical or mechanical problems Determine relative pump load or spot changes in loading Detect changes in downhole fluid condition

Changes in operating current indicate that the motor is reacting to a new input from the pump, well, or electrical system. The Motor Controller should shut the unit off if the current varies beyond acceptable limits

Amp Charts Amp charts are a valuable troubleshooting tool Amp charts record the motor current over time Trends in motor loading can be analyzed along with other unit data Certain downhole conditions give unique current signatures

Normal ChartA. May produce a curve that is below or above motor nameplate amperage B. Curve should be smooth and symmetrical C. Spike on startup is a normal occurrence on “across the line” starts

A m p s100 120 140 160

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1 23 45 67 89 111 133 155 177 199 221 243 265 287 309 331 353 375 397 419 441

Normal

Minutes

Pump Off

A. Starting Current Spike B. Normal Running Amps C. Pump Off Begins D. Unit Hits Underload Amps & Shuts Down

A m p s100 120 140 160

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1 23 45 67 89 111 133 155 177 199 221 243 265 287 309 331 353 375 397 419 441

Pump Off

Minutes

Pump Off Effects Production will be lower than anticipated– Lower fluid velocity past the motor – Higher than normal motor operating temperature

Excessive restarts of the unit– Mechanical stresses to unit shafts – Electrical stresses to cable and motor insulation system

Pump Off Causes & SolutionsCause Unit flow capacity is too large for the well Perforations

are restricted Well inflow performance has changed Unit was sized for future conditions

Solution Lower flow w/a surface choke or reduce operating Hz Chemical treatment Resize the unit, choke it back, or reduce operating Hz Choke it back or reduce operating Hz

Gassy Conditions BA

C

A. Current inrush on “across the line” startup B. Decreased gas %, increased density, (increased amps) increased pressure, increased flow, increased inlet velocity and increased gas % C. Too much gas, low density, (decreased amps) decreased pressure, decreased flow, low inlet velocity,

A m p s100 120 140 20 40 60 80

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1 23 45 67 89 111 133 155 177 199 221 243 265 287 309 331 353 375 397 419 441

Gassy Conditions

Minutes

Gassy Conditions Effects Stock tank barrels may be lower than anticipated– Volume seen by the pump would be higher than stock tank barrels due to gas breakout after leaving the pump discharge

Amperage fluctuations are caused by entrained and free gas in the fluid production Unit operates continuously without gas locking, therefore, not considered to be a significant problem

Gassy Conditions Causes and SolutionsCause Low pump intake pressure allows gas in solution to become free gas Gas builds up on the low pressure side of the impeller vane, partially blocking the flow area

Solution Lower pump or decrease the flow Implement some form of gas handling technology Not a significant problem unless the pump gas locks

No Underload ShutdownA B C D

A. Inrush current on “across the line” startup B. Running at design point amps C. Amps dropping due to fluid level drop in the well D. Running at near idle current with no shutdown