Electric submersible pump

You cannot see an ESP. Intake pressure, motor temperature and current tell you how it is doing.

An ESP sits thousands of feet down, out of reach until a rig pulls it. Its pump curve, the inflow from the reservoir and the cooling of its motor all follow equations we can write down. The twin puts the gauge and drive readings on those curves and says when the pump is drifting out of its range.

150 hp ESP, 2,000 bbl/d at 60 Hz, 200 stages, set at 6,800 ft

Built and run to API RP 11S, API RP 11S4

Start with one station or field See how we prove results

Flow: 2,001 bbl/d
Head: 5,138 ft
Motor load: 79%
Intake pressure: 938 psi

Anatomy and nameplate

1Intake pressure. Fluid over the pump. With the inflow curve, it gives flowing bottomhole pressure.
2Motor temperature. Winding temperature from the downhole gauge. Cooled only by the fluid going past.
3Drive frequency and current. Speed sets the pump curve. Current shows load, gas and underload.
4Discharge pressure. With intake pressure, gives the head the pump is making.
5Wellhead pressure. Back pressure from the flowline.
6Wellhead temperature. Fluid temperature at surface. Falls when flow falls.

Electric submersible pump nameplate
Pump
Type	Centrifugal, 200 stages, mixed flow
Design flow (BEP)	2,000 bbl/d at 60 Hz
Head at BEP	5,140 ft (25.7 ft per stage)
Shutoff head	6,939 ft
Efficiency at BEP	62%
Recommended range	75% to 125% of BEP (1,500 to 2,500 bbl/d at 60 Hz)
Intake	Rotary gas separator
Motor and drive
Motor	150 hp, 2,300 V, 40 A, 5.4 in OD
Drive	Variable speed drive with step-up transformer
Load at design	118 hp, 79% of nameplate, 32.7 A
Downhole gauge	Intake pressure, motor temperature, discharge pressure
Motor temperature limit	177 °C
Well
Setting depth	6,800 ft, perforations at 7,000 ft
Casing	7 in, 6.276 in ID
Reservoir pressure	2,400 psi, Vogel q_max 2,600 bbl/d
Operating point	2,001 bbl/d at 5,138 ft, intake 938 psi
Fluid	80% water cut, 0.42 psi/ft
Flow past the motor	2.3 ft/s at design, 1 ft/s at 858 bbl/d

From the well to market

Wells lift the fluid. The separator splits it. Oil goes to the tank battery and gas to the compressor station, and both leave by pipeline for processing.

Well fluid
Crude oil
Gas
Has its own twin page

The physics

The equations behind every curve on this page.

Affinity laws

Q ∝ f H ∝ f² P ∝ f³

The drive moves the whole pump curve. Ten percent less speed is 19% less head.

Inflow (Vogel)

q/q_max = 1 − 0.2·(Pwf/Pr) − 0.8·(Pwf/Pr)²

How much the reservoir gives for each step down in bottomhole pressure.

Head the well asks for

TDH = (P_wh + g·D + ΔP_f − PIP) / g

Lift to surface plus friction and back pressure, less what the fluid over the pump already pushes.

Motor cooling

ΔT ∝ losses / h h ∝ v^0.8

Fluid past the motor carries the heat away. 2.3 ft/s at design.

Where the pump runs

The pump curve, the drive frequency and the reservoir decide the flow together. The point moves as the reservoir drops.

Operating point on the pump curve

200 stages. Shaded band is the recommended range at 60 Hz.

60 Hz
50 Hz
66 Hz
Well today, 2,400 psi
Well a year on, 1,900 psi

Today: 2,001 bbl/d at 5,138 ft, 118 hp
A year on: 1,429 bbl/d, below range

The pump makes the head on its curve. The well asks for the head on its own curve. Where they cross is where it runs. As the reservoir drops, that point slides left, out of the range, and the stages start to ride on their downthrust washers.

Q ∝ f, H ∝ f², P ∝ f³ q/q_max = 1 − 0.2·(Pwf/Pr) − 0.8·(Pwf/Pr)²

Gas and heat

Gas and low flow are the two things that kill ESPs early. Each leaves its own pattern in the gauge and the drive.

Intake pressure and current through a gas slug

60 Hz, no change at the drive

Intake pressure
Motor current (right axis)

Current, normal: 32.7 A
Current, low point: 16.6 A
Intake pressure, peak: 1,105 psi

Gas cuts the head the stages can make. Flow stops, current falls toward no-load, and liquid builds up over the pump. Current alone looks like an underload trip. Current falling while intake pressure climbs says gas.

dPIP/dt = g · (q_in − q_pump) / A_annulus

Motor temperature against flow past the motor

Design load 118 hp, well at 95 °C, 5.4 in motor in 6.276 in casing

Winding temperature

The only thing cooling the motor is the well fluid flowing past it. Cut the flow and the winding heats up fast, long before the current looks wrong.

ΔT ∝ motor losses / h h ∝ v^0.8 v = Q / A_annulus

Failure modes

What breaks, what it looks like, what the twin does about it.

Failure mode	The physics	Signals that show it	How the twin catches it
Gas lock	Free gas fills the stages, which cannot make head with gas, so flow stops.	Current falls toward no-load. Intake pressure climbs. Wellhead temperature drops.	Reads current and intake pressure together, so gas is not mistaken for an underload or a broken shaft.
Running outside the recommended range	Below the range the stages ride down on their thrust washers. Above it they ride up.	Operating point left or right of the range on the curve. Vibration where the gauge has it.	Places each reading on the curve at the drive frequency and flags time below 75% or above 125% of BEP.
Scale or solids	Deposits narrow the stage passages, so each stage makes less head.	Discharge minus intake pressure falls at the same flow and frequency. Current creeps up.	Compares head made with the curve and trends the loss stage by stage.
Motor insulation breakdown	Heat and well fluid wear down the winding insulation.	Motor temperature high for the load. Phase imbalance and insulation resistance at the drive.	Works out the expected winding temperature from load and flow, and adds up the hours spent hot.
Cable faults	Gas and pressure cycling break down the cable insulation along the tubing.	Phase current imbalance. Ground fault readings at the drive.	Trends imbalance and leakage from the drive against the motor load.

What the twin does not do

The drive keeps its own protection. Underload, overload and ground fault trips stay with it. TwinEdge is never in the safety loop.
We suggest frequency changes. Your people make them at the drive or through SCADA.

How we catch it early

A physics twin and a PINN, working on one electric submersible pump.

The twin is a set of equations for this machine, tuned to its nameplate. Give it the flow, speed and conditions and it returns what every reading should be. It always gives the same answer for the same inputs.

A physics-informed neural network, or PINN, sits on top. It is trained on the plant’s own data and it is penalized whenever it breaks a physics rule. So it can only learn what the equations leave out: wear, fouling, friction. It cannot invent an answer that the machine could never produce.

Step 1
Measure
Flow, pressure, current, temperature, vibration. Whatever the asset already has.
Step 2
Physics twin
The equations of this machine, set to its nameplate. It says what the readings should be right now.
Step 3
Residual
Measured minus expected. Demand, weather and speed are already taken out.
Step 4
PINN
A small neural network that learns the cause of the gap, under the physics rules.
Step 5
Finding
A named cause, a date, and the kWh or hours at stake. An engineer reviews it.

loss = (measured − predicted)² + λ · (physics residual)²

The second term is the rulebook. It is zero when the network obeys the equations.

Why this beats black-box AI

A black-box model learns patterns from history. It needs examples of each failure, and it goes quiet when the pump runs at a point it has not seen. The twin starts from physics, so it works on day one. The PINN adds what physics cannot know about this particular machine.

That is also what makes the savings countable. The baseline is a calculation, not a guess, so the gap between baseline and meter is a number a customer can check.

What the twin checks on this asset

Operating point on the pump curve at the drive frequency
Intake pressure against the inflow curve
Motor temperature against load and flow past the motor
Current and intake pressure read together for gas

	Fixed alarm	Black-box AI	Twin + PINN
Needs failure history to learn	No	Yes, lots	No
Says what is wrong	No	Rarely	Yes, by name
Works at a flow it has never seen	No	Often fails	Yes, the equations still hold
Puts a number on the saving	No	No	Yes, in kWh and dollars
Lead time on slow wear	Late	Varies	Weeks to months
Every number can be traced	Yes	No	Yes, to an equation

What the twin puts a number on

Energy and cost, from the equations.

Design point

2,001 bbl/d

5,138 ft at 118 hp, 100% of BEP

A year on, at 60 Hz

71% of BEP

1,429 bbl/d with the reservoir at 1,900 psi. Below the range.

Each day the well is down

400 bbl oil

$28,015 at $70 per bbl

Motor at 900 bbl/d

150 °C

Against 125 °C at design flow, same load

What we do for you

We watch it. We catch it. We prove it.

Our reliability engineers run the twin on your electric submersible pump, review every finding, and help your crew fix it. After the repair we compare the meter to the baseline and write the result in the ledger.

Start with one station or field See the 90-day pilot

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