Artificial Lift Systems Flashcards

In ESP systems, what is the significance of the motor's 'nameplate amperage' during operation in high-temperature wells?

Answer: Nameplate amperage is the maximum rated current; high temperatures de-rate motor capacity, risking overload at nameplate current

High bottomhole temperatures reduce motor efficiency and increase resistance, so operating at nameplate amperage in hot wells can cause the motor to overheat and fail prematurely.

Which condition is indicated when a sucker rod pump's dynamometer card shows a 'flat top and flat bottom' (box-shaped) pattern?

Answer: Normal pump operation with effective valve action and full fluid load

A box-shaped (flat top and bottom) dynamometer card indicates ideal pump performance with proper valve seating, full fluid fill, and correct load transfer.

What is the function of a 'standing valve' in a sucker rod pump?

Answer: To prevent fluid from falling back into the formation during the upstroke by acting as a check valve at the pump barrel bottom

The standing valve is a check valve at the bottom of the pump barrel that opens on the upstroke to allow fluid entry and closes on the downstroke to retain fluid above it.

For gas-lift design, what is the 'point of equilibrium' (or operating valve depth)?

Answer: The deepest gas-lift valve at which the available injection pressure can unload and maintain continuous gas injection

The point of equilibrium is the deepest valve depth where available surface injection pressure (accounting for gas column weight) equals the required tubing pressure to inject gas.

Which parameter most directly affects the electrical power consumption of an ESP installation?

Answer: Flow rate, total dynamic head, and pump efficiency

ESP power consumption is governed by the hydraulic power required (flow rate × total dynamic head) divided by pump and motor efficiency.

In a PCP system, what is 'rotor backspin' and why is it hazardous?

Answer: Reverse rotation of the rotor after shutdown due to fluid head, which can unscrew rod connections if not controlled with a backspin brake

Rotor backspin occurs when the fluid column above the pump drives the rotor in reverse after shutdown; without a backspin brake, the rotating rod string can unscrew at couplings.

What diagnostic tool is used to measure downhole ESP performance parameters such as intake pressure, temperature, and vibration in real time?

Answer: Downhole monitoring gauge (DHG) or permanent downhole gauge (PDG) integrated with the ESP

Downhole monitoring gauges (DHGs) are installed as part of the ESP string to transmit real-time pressure, temperature, and vibration data to surface via the power cable.