电潜泵运行过程中所监测的参数

ESP Operating ParametersESP Operation Once an ESP system is commissioned, the operator plays a key role in the systems 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 costlyOperating 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 RateProduction 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 ESPPump 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 wearIncreases or decreases in PIP can indicate a change in the pump performance, well inflow, or installation integrityMotor 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 conditionChanges 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 limitsAmp 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 signaturesNormal ChartA.May produce a curve that is below or above motor nameplate amperageB.Curve should be smooth and symmetricalC.Spike on startup is a normal occurrence on “across the line” startsPump OffA. Starting Current SpikeB. Normal Running AmpsC. Pump Off BeginsD. Unit Hits Underload Amps & Shuts DownPump Off Effects Production will be lower than anticipated Lower fluid velocity past the motorHigher than normal motor operating temperature Excessive restarts of the unitMechanical stresses to unit shaftsElectrical stresses to cable and motor insulation systemPump 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 conditionsSolution 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 HzGassy ConditionsA.Current inrush on “across the line” startupB.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, decreased gas %A B CGassy Conditions Effects Stock tank barrels may be lower than anticipatedVolume 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 problemGassy 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 areaSolution Lower pump or decrease the flow Implement some form of gas handling technology Not a significant problem unless the pump gas locksNo Underload ShutdownA.Inrush current on “across the line” startupB.Running at design point ampsC.Amps dropping due to fluid level drop in the wellD.Running at near idle current with no shutdownA B C DNo Underload Shutdown Effects Motor will run hot due to no flow past the motor for cooling Possible motor lead extension cable failure due to pump running hot Extended operation in this mode will result in motor failure due to overheating Possible seal section failure due to lack of lubricity and exceeding temperature of elastomersNo Underload Shutdown Causes and SolutionsCause Unit oversized for application Underload shutdown faulty or incorrectly set Running against a closed surface valveSolution Reduce flow by increasing tubing back pressure, by lowering hertz or re-circulation Repair or re-adjust underload setting Verify surface valves are open and chokes properly adjustedA.Inrush current on “across the line” startupB.Unit pulling design point ampsC.Unit shuts down due to external signalD.Times out and re-startsExternal ShutdownA B C DExternal Shutdown Effects Could result in excessive cycling Limiting cyclic operations should prolong run life Possible startup during backspin if auto restart timer is not adjusted to allow time for backspin Potential for twisted or broken shafts if started during backspinExternal Shutdown Causes and SolutionsCause Typically a programmed function Tank level switches, high-low pressures switches, timers Unit cycled to control total productionSolution Limit cyclic operation Allow sufficient time for backspin, install backspin relay Increase tubing pressure, decrease hertzPumping DebrisA.Inrush current on “across the line” startupB.Erratic amperage due to pumping debrisC.Pumping clean fluid and amperage has stabilizedABCPumping Debris Effects Pump could become plugged with debrisdecrease in productionreduced cooling for the motor Pump could become locked upMay require pulling from the well Overload