# US 11,905,826 B2 · Clock calibration of remote systems by roundtrip time

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,905,826 B2
- Document ID: US11905826B2
- Status: Granted
- Kind: B2
- Application number: 16/346,416
- Filed: 2018-05-31
- Published: 2021-12-02
- Granted: 2024-02-20
- Earliest claimed: 2018-05-31
- Assignees: Halliburton Energy Services, Inc.
- Applicants: Halliburton Energy Services, Inc.
- Inventors: Imran Sharif Vehra; Zinovy B. Krugliak; Randal T. Beste; Matthew Chase Griffing; Christopher A. Golla; Wenhao Chen; Rameez Balagamwala
- Web page: https://patentgrep.com/patent/US11905826B2

## 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
- E21B 49/00: Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
- G01V 3/34: Transmitting data to recording or processing apparatus; Recording data
- G01V 11/002: {Details, e.g. power supply systems for logging instruments, transmitting or recording data, specially adapted for well logging, also if the prospecting method is irrelevant (means for transmitting well survey signals E21B47/12; signal transmission systems in general G08C; transmission in general H04B)}
- G01V 13/00: Manufacturing, calibrating, cleaning, or repairing instruments or devices covered by groups G01V1/00 – G01V11/00
- G01V 2200/12: Clock synchronization-related issues
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- 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

A method for calibrating a downhole tool may comprise disposing a downhole tool in a borehole, transmitting a signal from a master module disposed on the first device to a module disposed on the second device, transmitting a return signal from the module to the master module, receiving the return signal with the master module, measuring a tone enabled delay for the signal to travel from the master module to the module, and determining a time delay of a return signal to travel from the module to the master module. A well measurement system may comprise a downhole tool. The downhole tool may further comprise a first device and a master module disposed on the first device, wherein the master module may comprise a master transmitter and a master receiver. In examples, the downhole tool may further comprise a second device and a module disposed on the second device.

## Claims

### Claim 1

A method for calibrating a downhole tool, comprising:
disposing the downhole tool in a borehole, wherein the downhole tool comprises a first device and a second device;
transmitting a signal from a master module disposed on the first device to a module disposed on the second device;
transmitting a return signal from the module to the master module
determining Tdd of a time for the signal to travel from the master module to the module, wherein the Tdd=(Counter-Tf-T4-T3)/2, wherein the Counter is a second time for the signal to travel from the master module to the module and back to the master module as measured by the master module, the T4 is a master module signal detection time, the Tf is a fixed time delay and the T3 is a module signal detection time;
determining T2, wherein the T2=T3+(Tdd-T1), wherein the T2 is a time delay and the T1 is a time it takes for the signal to be transmitted and detected at the master module;
receiving the return signal with the master module; and
measuring the time for the signal to travel from the master module to the module.

### Claim 2 (depends on 1)

The method of claim 1, wherein the master module comprises a master transmitter and a master receiver.

### Claim 3 (depends on 2)

The method of claim 2, further comprising changing the master module from a line driver controlled by the master transmitter to a line receiver controlled by the master receiver to receive the return signal.

### Claim 4 (depends on 3)

The method of claim 3, wherein the module comprises a receiver and a transmitter, and wherein the module is capable of changing between a line receiver mode and a line transmitter mode.

### Claim 5 (depends on 1)

The method of claim 1, further comprising counting a number of transmitter clock ticks during the second time for the signal to travel from the master module to the module and back to the master module.

### Claim 6 (depends on 5)

The method of claim 5, further comprising applying an error adjustment with the T2.

### Claim 7 (depends on 1)

The method of claim 1, wherein the signal is 1 hertz to 1 gigahertz.

### Claim 8 (depends on 1)

The method of claim 1, further comprising measuring resistivity or conductivity of a formation with the first device and/or the second device to obtain a formation property.

### Claim 9 (depends on 8)

The method of claim 8, further comprising:
calibrating the formation property with the time delay; and
displaying a calibrated measurement of the formation property.

### Claim 10 (depends on 9)

The method of claim 9, wherein the time delay includes one or more measurements from propagation delay, phase shift, or temperature effects.

### Claim 11 (depends on 1)

The method of claim 1, further comprising applying a time delay to a phase measurement.

### Claim 12

A well measurement system comprising:
a downhole tool, wherein the downhole tool comprises:
a first device;
a master module disposed on the first device, wherein the master module comprises a master transmitter and a master receiver;
a second device;
a module disposed on the second device, wherein the module comprises a transmitter and a receiver; and
an information handling system for:
transmitting a signal to the module,
changing the master module from a line driver controlled by the master transmitter to a line receiver controlled by the master receiver,
transmitting a return signal from the module to the master module
determining Tdd of a time for the signal to travel from the master module to the module, wherein the Tdd=(Counter-Tf-T4-T3)/2, wherein the Counter is a second time for the signal to travel from the master module to the module and back to the master module as measured by the master module, the T4 is a master module signal detection time, the Tf is a fixed time delay and the T3 is a module signal detection time,
determining T2, wherein the T2=T3+(Tdd-T1), wherein the T2 is a time delay and the T1 is a time it takes for the signal to be transmitted and detected at the master module,
receiving the return signal from the module with the master module, and
measuring a time for the signal to travel from the master module to the module and the return signal back to the master module.

### Claim 13 (depends on 12)

The well measurement system of claim 12, wherein the time delay comprises propagation delay, phase shift, and/or or temperature effects.

### Claim 14 (depends on 12)

The well measurement system of claim 12, wherein the information handling system further records a measurement of resistivity or conductivity of a formation from the first device and/or the second device to obtain a formation property.

### Claim 15 (depends on 12)

The well measurement system of claim 12, wherein the information handling system further calibrates a formation property with the time delay.

### Claim 16 (depends on 12)

The well measurement system of claim 12, further comprising a third device,
wherein the third device comprises a second module, and
wherein the information handling system further:
controls the master module to transmit a signal to the second module,
changes the master module from a line driver controlled by the master transmitter to a line receiver controlled by the master receiver,
receives a return signal from the second module with the master module,
measures a time for the signal transmitted to the second module to travel from the master module to the second module and the return signal received from the second module back to the master module from the second module, and
determines the time delay of the signal transmitted to the second module to travel from the master module to the second module.

### Claim 17 (depends on 16)

The well measurement system of claim 16, wherein the information handling system further records a measurement of resistivity or conductivity a formation from at least one of the first device, the second device, and the third device.

### Claim 18 (depends on 17)

The well measurement system of claim 17, wherein the time delay comprises propagation delay, phase shift, or temperature effects.

### Claim 19

A method for calibrating a downhole tool, comprising:
disposing the downhole tool in a borehole, wherein the downhole tool comprises a first device and a second device;
transmitting a signal from a master module disposed on the first device to a module disposed on the second device;
transmitting a return signal from the module to the master module after a fixed time delay;
receiving the return signal with the master module;
measuring a time for the signal to travel from the master module to the module;
determining Tdd of the time for the signal to travel from the master module to the module, wherein the Tdd=(Counter-Tf-T4-T3)/2, wherein the Counter is a time for the signal to travel from the master module to the module and back to the master module as measured by the master module, the Tf is the fixed time delay, the T4 is a master module signal detection time, and the T3 is a module signal detection time;
determining T2, wherein the T2=T3+(Tdd-T1), wherein the T2 is a time delay and the T1 is a time it takes for the signal to be transmitted and detected at the master module.

### Claim 20

A method for calibrating a downhole tool, comprising:
disposing the downhole tool in a borehole, wherein the downhole tool comprises a first device and a second device;
transmitting a signal from a master module disposed on the first device to a module disposed on the second device;
transmitting a return signal from the module to the master module after a fixed time delay;
receiving the return signal with the master module;
measuring a time for the signal to travel from the master module to the module;
determining Tdd of the time for the signal to travel from the master module to the module, wherein the Tdd=(Counter-Tf-T4-T3)/2, wherein the Counter is a time for the signal to travel from the master module to the module and back to the master module as measured by the master module, the Tf is the fixed time delay, the T4 is a master module signal detection time, and the T3 is a module signal detection time;
determining T2, wherein the T2=T3+(Tdd-T1), wherein the T2 is a time delay and the T1 is a time it takes for the signal to be transmitted and detected at the master module; and
counting a number of transmitter clock ticks during the time for the signal to travel from the master module to the module and back to the master module.

### Claim 21

A method for calibrating a downhole tool, comprising:
disposing the downhole tool in a borehole, wherein the downhole tool comprises a first device and a second device;
transmitting a signal from a master module disposed on the first device to a module disposed on the second device;
transmitting a return signal from the module to the master module after a fixed time delay;
receiving the return signal with the master module;
determining Tdd of the time for the signal to travel from the master module to the module, wherein the Tdd=(Counter-Tf-T4-T3)/2, wherein the Counter is a time for the signal to travel from the master module to the module and back to the master module as measured by the master module, the Tf is the fixed time delay, the T4 is a master module signal detection time, and the T3 is a module signal detection time;
determining T2, wherein the T2=T3+(Tdd-T1), wherein the T2 is a time delay and the T1 is a time it takes for the signal to be transmitted and detected at the master module;
counting a number of transmitter clock ticks during the time for the signal to travel from the master module to the module and back to the master module; and
applying an error adjustment with the T2.