Electric submersible pump
An electric submersible pump (ESP), comprising: an intake that suctions fluids into the ESP, wherein the fluids include a mixture of gas, water, and oil; a discharge that discharges the fluids from the ESP; an acoustic intake transducer that determines the speed of sound in the fluids suctioned into the ESP at the intake; and a first acoustic discharge transducer that determines the speed of sound in the fluids discharged from the ESP, wherein the speed of sound of the fluid at both intake and discharge is used to calculate a gas volume fraction difference of the multiphase fluid mixture across the intake and discharge of the pump, and wherein the gas volume fraction difference is used as feedback to control the ESP.
1. An electric submersible pump (ESP), comprising:
an intake that suctions fluids into the ESP, wherein the fluids comprise a mixture of gas, water, and oil;
a discharge that discharges the fluids from the ESP;
an acoustic intake transducer that determines the speed of sound in the fluids suctioned into the ESP at the intake; and
a first acoustic discharge transducer that determines the speed of sound in the fluids discharged from the ESP,
wherein the speed of sound of the fluid at both intake and discharge is used to calculate a gas volume fraction difference of the multiphase fluid mixture across the intake and discharge of the pump, and
wherein the gas volume fraction difference is used as feedback to control the ESP.
2. The ESP according to claim 1 , wherein operation of the ESP is controlled using the gas volume fraction difference to reduce gas breakout, minimize gas surging, and minimize gas lockout.
3. The ESP according to claim 1 , further comprising a density acoustic discharge transducer that measures a pressure-based density of the fluids discharged from the ESP.
4. The ESP according to claim 1 , further comprising a second acoustic discharge transducer, wherein the first and second acoustic discharge transducer determine the speed of sound in the fluids discharged from the ESP.
5. The ESP according to claim 1 , further comprising a second acoustic intake transducer, wherein the first and second acoustic intake transducer determine the speed of sound in the fluids discharged from the ESP.
6. The ESP according to claim 1 , wherein the first acoustic discharge transducer is a mechanical transducer that converts sound waves into mechanical signals or vice versa.
7. The ESP according to claim 1 , wherein the first acoustic discharge transducer is an electrical transducer that converts sound waves into electrical signals.
8. The ESP according to claim 7 , wherein the first acoustic discharge transducer is a linear variable differential transformer that measures displacement or position changes by an electrical signal.
9. The ESP according to claim 1 , further comprising a pressure-based density sensor at the discharge of the ESP that measures a pressure-based density of the fluids discharged from the ESP.
10. A method for determining a gas content in fluids transported by an ESP, comprising:
obtaining a speed of sound in the fluids, wherein the fluids comprise a mixture of gas, water, and oil;
determining the gas content using the speed of sound in the fluids; and
feeding back the determined gas content to control operation of the ESP,
wherein the speed of sound in the fluids exiting the ESP is determined.
11. The method according to claim 10 , further comprising:
obtaining a speed of sound in fluids entering the ESP, and
determining a gradient of the gas content in the fluids using the speed of sound in the fluids entering and exiting the ESP.
12. The method according to claim 10 , further comprising:
changing at least one operation parameter of the ESP based on the determined gas content to reduce gas breakout, minimize gas surging, or minimize gas lockout.
13. The method according to claim 12 , wherein the at least one operation parameter of the ESP comprises power, load, rotational speed, and driving voltage of the ESP.
14. The method according to claim 10 , wherein the speed of sound in the fluids exiting the ESP is determined by
1
c
D
2
=
[
(
1
-
ϕ
G
D
)
ρ
L
+
ϕ
G
D
ρ
G
]
[
(
1
-
ϕ
G
D
)
ρ
L
c
L
2
+
ϕ
G
D
ρ
G
c
G
2
]
,
where ϕ GD is the volume fraction of the gas phases at the discharge, c L is the speed of sound in the liquid phase, c G is the speed of sound in the gas phase, ρ L is the liquid phase density, and ρ G is the gas phase density.
15. The method according to claim 11 , wherein the speed of sound in the fluids entering the ESP is determined by
1
c
I
2
=
[
(
1
-
ϕ
GI
)
ρ
L
+
ϕ
GI
ρ
G
]
[
(
1
-
ϕ
GI
)
ρ
L
c
L
2
+
ϕ
GI
ρ
G
c
G
2
]
,
where ϕ GI is the volume fraction of the gas phases at the intake, c L is the speed of sound in the liquid phase, c G is the speed of sound in the gas phase, ρ L is the liquid phase density, and ρ G is the gas phase density.
16. The method according to claim 10 , further comprising:
obtaining a pressure-based density of the fluids, and
determining the gas content in the fluids using the speed of sound in the fluids and the pressure-based density of the fluids.
17. The method according to claim 10 , wherein the speed of sound in the fluids is determined by calculating a time of flight of an acoustic pulse propagating through the fluids.
18. The method according to claim 17 , wherein a time of flight is calculated by issuing the acoustic pulse into the fluids, reflecting the acoustic pulse off of a surface, and measuring the time of flight for the reflected acoustic pulse to impinge on an acoustic transducer.