# US 11,994,021 B2 · Downhole wire integrity and propagation delay determination by signal reflection

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- Number: US 11,994,021 B2
- Document ID: US11994021B2
- Status: Granted
- Kind: B2
- Application number: 16/963,460
- Filed: 2018-02-20
- Published: 2021-02-18
- Granted: 2024-05-28
- Earliest claimed: 2018-02-20
- Assignees: Halliburton Energy Services, Inc.
- Applicants: Halliburton Energy Services, Inc.
- Inventors: Imran Sharif Vehra; Christopher Golla; Matthew Chase Griffing; Zinovy B. Krugliak
- Web page: https://patentgrep.com/patent/US11994021B2

## CPC

- E21B 47/12: Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling
- G01R 31/11: using pulse reflection methods
- G01V 3/18: specially adapted for well-logging
- E21B 19/18: Connecting or disconnecting drill bit and drilling pipe
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02)

## Abstract

An apparatus, method, and system for determining the propagation delay for a downhole wire and/or for monitoring the integrity of a downhole wire. The apparatus includes a first tool component and a second tool component spaced apart from the first tool component and communicatively coupled by a wire. The tool components include impedance altering devices configured to alter, for a predetermined period of time, either the source impedance at a first termination point of the wire and/or the load impedance at a second termination point of the wire sufficient to generate a characteristic signal reflection upon the transmission of a signal along a length of the wire between the first tool component and the second tool component.

## Claims

### Claim 1

An apparatus comprising:
a first tool component,
a second tool component spaced apart from the first tool component;
a wire having a first termination point and a second termination point, the wire communicatively coupling the first tool component and the second tool component and having a characteristic line impedance, wherein:
the first tool component is coupled to a first termination point of the wire and the second tool component is coupled to a second termination point of the wire, the first termination point of the wire having a source impedance and the second termination point of the wire having a load impedance,
the first tool component includes a first impedance altering device and the second tool component includes a second impedance altering device, the first and second impedance altering devices configured to alter, for a first predetermined period of time, at least one of the source impedance and the load impedance sufficient to generate a characteristic signal reflection upon transmission of a signal along a length of wire between the first tool component and the second tool component,
the first tool component is configured to transmit a clock signal along the length of wire between the first tool component and the second tool component during the first predetermined period of time, and
wherein the first tool component is configured to receive one or more reflected clock signals reflected during the first predetermined period of time; and
a computing device coupled to the first tool component that identifies a propagation delay associated with the one or more reflected clock signals, wherein a measurement associated with at least one of the first tool component or the second tool component is corrected based on the identified propagation delay.

### Claim 2 (depends on 1)

The apparatus according to claim 1, wherein the propagation delay corresponds to the time of propagation along a length of the wire between the first termination point and the second termination point.

### Claim 3 (depends on 2)

The apparatus according to claim 2, wherein the computing device is further configured to determine a wire integrity characteristic based on the one or more reflected clock signals.

### Claim 4 (depends on 2)

The apparatus according to claim 2, wherein the impedance altering devices are configured to generate, for a first predetermined period of time, an impedance mismatch between the source impedance, the load impedance, and characteristic line impedance (Zo) sufficient to generate the characteristic signal reflection upon the transmission of the signal along the length of wire between the first tool component and the second tool component.

### Claim 5 (depends on 2)

The apparatus according to claim 2, wherein the impedance altering devices are configured to generate a source impedance sufficient to generate the characteristic signal reflection upon the transmission of the signal along a length of wire between the first tool component and the second tool component.

### Claim 6 (depends on 2)

The apparatus according to claim 2, wherein the impedance altering devices are configured to alter the load impedance by transmitting a command signal to the second tool component causing the second tool component to, upon receiving the command signal, generate a short for a first predetermined period of time along a length of the wire between the first tool component and the second tool component, wherein the short results in a smaller impedance than the characteristic line impedance (<<Zo) along the length of wire between the first tool component and the second tool component.

### Claim 7 (depends on 2)

The apparatus according to claim 2, wherein the impedance altering devices are configured to alter, for a first predetermined period of time, at least one of the source impedance and the load impedance such that the source impedance is greater than the characteristic line impedance (>>Zo) and the load impedance is less than the characteristic line impedance (<<Zo).

### Claim 8 (depends on 2)

The apparatus according to claim 2, wherein the impedance altering devices are configured to alter, for a first predetermined period of time, at least one of the source impedance and the load impedance such that the load impedance is either greater than the source characteristic line impedance (>>Zo) or less than the characteristic line impedance (<<Zo).

### Claim 9 (depends on 1)

The apparatus according to claim 1, further comprising a third tool component spaced apart from the first and second tool components, the wire communicatively coupling the third tool component with the first tool component, wherein:
the wire has a third termination point coupled to the third tool component, the third termination point having a second load impedance;
third tool component includes a third impedance altering device, the third impedance altering device configured to alter, for a second predetermined period of time, at least one of the source impedance and the second load impedance sufficient to generate a second characteristic signal reflection upon the transmission of a second signal along a length of wire between the first tool component and the third tool component;
the first tool component is configured to transmit a second clock signal along the length of wire between the first tool component and the third tool component during the second predetermined period of time; and
the first tool component is configured to receive one or more reflections of the second clock signal during the second predetermined period of time.

### Claim 10 (depends on 9)

The apparatus according to claim 9, wherein the computing device identifies:
a second propagation delay based on the one or more reflections of the second clock signal.

### Claim 11 (depends on 10)

The apparatus according to claim 10, wherein the computing device is further configured to identify:
a first wire integrity characteristic based on the one or more reflected clock signals reflected during the first predetermined period of time; and
a second wire integrity characteristic based on the one or more reflections of the second clock signal.

### Claim 12 (depends on 1)

The apparatus according to claim 1, wherein the first tool component includes a line driver and the first impedance altering device includes a source resistor, and the line driver is configured to transmit the clock signal through the source resistor.

### Claim 13 (depends on 12)

The apparatus according to claim 12, wherein the first tool component further includes:
a counter circuit; and
a detector located between the source resistor and the second tool component, the detector configured to convert the at least one of the one or more reflected clock signals to a square wave or a clean edge/pulse, wherein operation of the counter circuit facilitates identification of a frequency of the converted reflected clock signal or facilitates measurement of a round trip time associated with transmission of the clock signal and reception of the one or more reflected clock signals.

### Claim 14 (depends on 1)

The apparatus according to claim 1, wherein the first tool component includes a transmitter and the second tool component includes a receiver of a resistivity logging tool.

### Claim 15 (depends on 1)

The apparatus according to claim 1, wherein the wire between the first tool component and the second tool component comprises a length of at least 25 feet.

### Claim 16

A method comprising:
altering, for a first predetermined period of time, at least one of a source impedance of a first end of a wire and a load impedance of a second end of the wire, said altering sufficient to generate a characteristic signal reflection upon transmission of a signal along a length of wire between a first tool component and a second tool component;
transmitting, from the first tool component, during the first predetermined period of time, a clock signal along the length of the wire between the first tool component and the second tool component;
receiving, at the first tool component, one or more reflected clock signals reflected during the first predetermined period of time; and
identifying a propagation delay associated with the one or more reflected clock signals, wherein a measurement associated with at least one of the first tool component or the second tool component is corrected based on the identified propagation delay.

### Claim 17 (depends on 16)

The method according to claim 16, further comprising transmitting from the first tool component, a clock synchronization signal to the second tool component, based on the propagation delay.

### Claim 18 (depends on 16)

The method according to claim 16, wherein the corrected measurement is a tool measurement.

### Claim 19 (depends on 16)

The method according to claim 16, wherein the measurement is a resistivity measurement made based on the first tool component including a transmitter and the second tool component including a receiver.

### Claim 20 (depends on 19)

The method according to claim 19, further comprising identifying a phase correction of the resistivity measurement.

### Claim 21

A method of monitoring Phell integrity of a downhole wire, the method comprising:
altering, for a first predetermined period of time, at least one of a source impedance of a first end of the wire and a load impedance of a second end of the wire, said altering sufficient to generate a characteristic signal reflection upon transmission of a signal along a length of the wire between a first tool component and a second tool component;
transmitting, from the first tool component, during the first predetermined period of time, a clock signal along the length of the wire between the first tool component and the second tool component;
receiving, at the first tool component, one or more reflected clock signals reflected during the first predetermined period of time; and
identifying a wire integrity characteristic based on the one or more reflected clock signals reflected during the first predetermined period of time, wherein a measurement associated with at least one of the first tool component or the second tool component is corrected based on the identified wire integrity characteristic.

### Claim 22 (depends on 21)

The method according to claim 21, wherein the wire integrity characteristic is selected from the group consisting of a change in propagation delay, a change in reflected signal amplitude or frequency, a change in decay of the reflected signal, and a change in a reflection coefficient.

### Claim 23 (depends on 21)

The method according to claim 21, further comprising modifying an operational parameter based upon the wire integrity characteristic.

### Claim 24 (depends on 21)

The method according to claim 21, wherein the wire integrity characteristic corresponds to an integrity of a bus of a resistivity tool, the method further comprising altering a resistivity logging tool operational parameter based on the wire integrity characteristic.

### Claim 25

A system comprising:
a wire;
a first tool component that includes a first impedance altering device that is controllably coupled to a first termination point of the wire via a first switch;
a second tool component that includes a second impedance altering device that is controllably coupled to a second termination point of the wire via a second switch;
a third tool component that includes a third impedance altering device that is controllably coupled to a third termination point of the wire via a third switch, wherein the first tool component, the second tool component, and the third tool component are spaced apart along a wellbore; and
a computing device coupled to the first tool component that controls one or more of the first switch the second switch and the third switch to:
alter, for a first predetermined period of time, at least one of a source impedance or a first load impedance such that a first characteristic signal reflection is generated upon transmission of a first signal along a length of wire between the first tool component and the second tool component,
alter, for a second period of time, at least one of the source impedance and the second load impedance such that a second characteristic signal reflection is generated upon the transmission of a second signal along a length of wire between the first tool component and the third tool component, wherein:
the first tool component transmits a first clock signal along the length of wire between the first tool component and the second tool component during the first predetermined period of time,
the first tool component transmits a second clock signal along the length of wire between the first tool component and the third tool component during the second predetermined period of time,
the computing device identifies a first propagation delay or a first wire integrity characteristic based on a first set of one or more reflected clock signals reflected during the first predetermined period of time, the identification of the first propagation delay or the first wire integrity characteristic results in a measurement associated with at least one of the first tool component or the second tool component being corrected, and
the computing device identifies a second propagation delay or a second wire integrity characteristic based on a second set of one or more reflected clock signals reflected during the second predetermined period of time.