Measuring fluid conductivity

Patent metadata

Field	Value
Publication number	US-10209390-B2
Application number	US-201314889977-A
Country	US
Kind code	B2
Filing date	Aug 5, 2013
Priority date	Aug 5, 2013
Publication date	Feb 19, 2019
Grant date	Feb 19, 2019

Abstract

An apparatus includes a helical flow tube in a formation testing tool. A current injector injects an electromagnetic current into the flow tube. A receiver coil is positioned to produce a receiver coil signal in response to the electromagnetic current. A processor is coupled to the receiver coil to calculate a conductivity of a fluid flowing through the flow tube based on the receiver coil signal.

First claim

What is claimed is:

1. An apparatus comprising:
a helical flow tube in a formation testing tool;
a current injector to inject an electromagnetic current into the flow tube, wherein the current injector has two electrodes that extend into the flow tube;
a receiver coil positioned to produce a receiver coil signal in response to the electromagnetic current; and
a processor coupled to the receiver coil to calculate a conductivity of a fluid flowing through the flow tube based on the receiver coil signal;
wherein the processor calculates the conductivity of the fluid flowing through the flow tube as a measurement of the receiver coil signal in a complex domain multiplied by a real valued tool constant after a tool body signal is subtracted.

2. The apparatus of claim 1 wherein:
the receiver coil comprises a coil of wire in an insulating liner.

3. The apparatus of claim 1 further comprising:
a measurement circuit to receive the receiver coil signal; and
the measurement circuit to provide to the processor:
an amplitude signal representing the amplitude of the receiver coil signal; and
a phase signal representing the phase of the receiver coil signal.

4. An apparatus comprising:
a helical flow tube in a formation testing tool;
exactly one transmitter coil;
a receiver coil;
a resistance measurement device to measure a resistance of a fluid flowing through the flow tube; and
a processor;
wherein the transmitter coil, receiver coil, and processor are interconnected in such a way that the processor can calculate a conductivity of a fluid flowing through the helical flow tube,
wherein the transmitter coil and the receiver coil are a conductance measurement device to measure a conductance of the fluid flowing through the flow tube, and
wherein the processor reports a measurement of the resistance measurement device when the resistance of the fluid flowing through the flow tube is above a resistance threshold, and reports a measurement of the conductance measurement device when the conductance of the fluid flowing through the flow tube is above a conductance threshold.

5. The apparatus of claim 4 wherein:
the receiver coil comprises a coil of wire in an insulating liner.

6. The apparatus of claim 4 wherein:
the transmitter coil is coaxial with the receiver coil.

7. The apparatus of claim 4 wherein:
the processor reporting the measurement by the conductance measurement device of the conductance, σ, of the fluid includes the processor calculating:

σ
=

V
K

,

where:
V is a voltage measured at the receiver coil,

K
=

N
T

⁢

N
R

⁢

I
T

⁡

(

π
⁢

⁢

a
2

)

2

⁢

ω
2

⁢

μ
2

4
⁢
π
⁢

⁢
L

,

N T is the number of turns in the transmitter coil,
N R is the number of turns in the receiver coil,
I t and ω are the amplitude and angular frequency, respectively, of a time harmonic current generated in the transmitter coil,
a is the radius of the transmitter coil and the receiver coil,
μ is the permeability of the formation, and
L is the distance between transmitter coil and the receiver coil.

8. The apparatus of claim 4 wherein:
the processor reporting the measurement by the resistance measurement device of the resistance, ρ, of the fluid, includes the processor calculating:
ρ=RG,

where:

R
=

I
V

,

V is the voltage measured across a first electrode and a second electrode inserted in the fluid,
I is the current measured flowing through the fluid between the first electrode and the second electrode, and
G is a geometry factor determined during a calibration of the resistance measurement device.

9. The apparatus of claim 4 wherein:
the resistance measurement device comprises an electrode extending into the flow tube.

10. A method comprising:
inductively generating an inductively-generated current flow in a fluid in a flow tube using a first inductive device;
inductively measuring the inductively-generated current flow using a second inductive device;
resistively generating a resistively-generated current flow in the fluid using a resistive generator;
resistively measuring the resistively-generated current flow using a resistive sensor;
calculating with a processor in a downhole tool interconnected with the first inductive device and the second inductive device a conductivity of the fluid using the inductively measured current;
calculating with the processor interconnected with the resistive generator and the resistive sensor the resistivity of the fluid using the resistively measured current; and
wherein the processor reports the calculated resistivity when the calculated resistivity is above a resistance threshold and reports the calculated conductivity when the calculated conductivity is above a conductance threshold.

Assignees

• Zhang Wei
• Zhang Lizheng
• Gao Li
• Donderici Burkay
• Halliburton Energy Services Inc

Inventors

• Zhang Wei
• Zhang Lizheng
• Gao Li
• Donderici Burkay

Classifications

• E21B49/0875

  determining specific fluid parameters · CPC title

• G01V3/28 Primary

  using induction coils · CPC title

• G01N27/08

  which is flowing continuously · CPC title

• G01N27/023

  where the material is placed in the field of a coil · CPC title

• E21B49/088

  combined with sampling · CPC title