# US 12,000,730 B2 · System and method for monitoring subsurface steam chamber development using fiber optic cables

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- Number: US 12,000,730 B2
- Document ID: US12000730B2
- Status: Granted
- Kind: B2
- Application number: 17/722,735
- Filed: 2022-04-18
- Published: 2022-10-20
- Granted: 2024-06-04
- Earliest claimed: 2021-04-16
- Assignees: Cenovus Energy Inc.
- Applicants: Cenovus Energy Inc.
- Inventors: Anthony Kay; Hong Feng
- Web page: https://patentgrep.com/patent/US12000730B2

## CPC

- G01H 9/004: {using fibre optic sensors (light guides per se G02B6/00, acousto-optical devices specially adapted for gating or modulating in optical wave guides G02F1/125)}
- E21B 47/107: using acoustic means
- E21B 47/135: using light waves, e.g. infrared or ultraviolet waves
- E21B 43/24: using heat, e.g. steam injection
- G01H: MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS

## Abstract

Methods and systems are provided for monitoring subsurface steam chamber development in a thermal hydrocarbon recovery operation, which employ a fiber optic cable in a horizontal wellbore beneath the steam chamber as part of a distributed acoustic sensing technique in which the cable receives attenuated sound waves passing through the steam chamber and transmits a signal corresponding to the attenuated sound waves and unattenuated sound waves for subsequent signal processing.

## Claims

### Claim 1

A method for monitoring steam chamber development in a reservoir generated by a thermal hydrocarbon recovery operation, the method comprising the steps of:
a. drilling at least one horizontal wellbore as part of the thermal hydrocarbon recovery operation;
b. deploying a fiber optic cable in the at least one horizontal wellbore;
c. operating the thermal hydrocarbon recovery operation to form a steam chamber in the reservoir above the at least one horizontal wellbore;
d. locating a seismic wave source above and spaced from the steam chamber;
e. generating a plurality of seismic waves using the seismic wave source and receiving the plurality of seismic waves at the fiber optic cable that have passed through the reservoir, at least one of the plurality of seismic waves having passed from the seismic wave source and into and through the steam chamber and thereby being attenuated when passing through the steam chamber before receipt at the fiber optic cable forming at least one attenuated seismic wave, and the at least one attenuated seismic wave thereby providing information regarding steam chamber location within the reservoir between the seismic wave source and the fiber optic cable, and generating a signal including the information regarding the steam chamber location within the reservoir;
f. transmitting the signal along the fiber optic cable to a receiver including the information regarding the steam chamber location within the reservoir;
g. receiving the signal at the receiver; and
h. processing the signal to extract the information regarding the steam chamber location within the reservoir to monitor development of the steam chamber.

### Claim 2 (depends on 1)

The method of claim 1 wherein the seismic wave source is a piezoelectric source.

### Claim 3 (depends on 1)

The method of claim 1 wherein the seismic wave source is located in a vertical well.

### Claim 4 (depends on 3)

The method of claim 3 wherein the vertical well is an existing observation well that is part of the thermal hydrocarbon recovery operation.

### Claim 5 (depends on 1)

The method of claim 1 wherein the processing of the signal involves full-waveform inversion.