4-1 Amp Charts

A m p s
Minutes
Centrilift
4-1 Amp Charts
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
4-1 Amp Charts 6
Pump Off Effects
Production will be lower than anticipated
– Lower fluid velocity past the motor – Higher than normal motor operating temperature
Centrilift
4-1 Amp Charts 13
No Underload Shutdown
160 140 120
A 100 m 80 p 60 s
40 20 0 1 17 33 49 65 81 97 113 129 145 161 177 193 209 225 241 257 273 289
4-1 Amp Charts 5
Pump Off
160 140 120 100 80 60 40 20 0 1 23 45 67 89 111 133 155 177 199 221 243 265 287 309 331 353 375 397 419 441
A m p s
Minutes
Centrilift
Excessive restarts of the unit
– Mechanical stresses to unit shafts – Electrical stresses to cable and motor insulation system
Centrilift
4-1 Amp Charts 7
Centrilift
4-1 Amp Charts 3
Normal
160 140 120 100 80 60 40 20 0 1 23 45 67 89 111 133 155 177 199 221 243 265 287 309 331 353 375 397 419 441
A m p s
Minutes
Centrilift
4-1 Amp Charts 8
Gassy Conditions
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, decreased gas %
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
Centrilift
4-1 Amp Charts 15
No Underload Shutdown Causes and Solutions
Cause
Unit oversized for application
Solution
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 adjusted
A
B
C
Centrilift
4-1 Amp Charts 9
Gassy Conditions
140 120 100 80 60 40 20 0 1 23 45 67 89 111 133 155 177 199 221 243 265 287 309 331 353 375 397 419 441
10
Centrilift
4-1 Amp Charts 4
Pump Off
A. Starting Current Spike B. Normal Running Amps C. Pump Off Begins D. Unit Hits Underload Amps & Shuts Down
Centrilift
Solution
Limit cyclic operation Allow sufficient time for backspin, install backspin relay Increase tubing pressure, decrease hertz
Pump Off Causes & Solutions
Cause
Unit flow capacity is too large for the well Perforations are restricted Well inflow performance has changed Unit was sized for future conditions
14
Minutes
Centrilift
4-1 Amp Charts
No 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 elastomers
Underload shutdown faulty or incorrectly set Running against a closed surface valve
Centrilift
4-1 Amp Charts 16
External Shutdown
A. Inrush current on “across the line” startup B. Unit pulling design point amps C. Unit shuts down due to external signal D. Times out mp or decrease the flow Implement some form of gas handling technology Not a significant problem unless the pump gas locks
Centrilift
4-1 Amp Charts 12
Centrilift
4-1 Amp Charts 11
Gassy Conditions Causes and Solutions
Cause
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
SPH, p.165-192
Centrilift
4-1 Amp Charts 2
Normal Chart
A. 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
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
Centrilift
Recording Ammeter Charts
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 Confirm chart calibration and pin condition