Downhole Fluid Tracking With Distributed Acoustic Sensing

A method that comprises:

• acquiring distributed acoustic sensing (DAS) measurements along a borehole;
• processing the measurements to detect one or more acoustic signature contrasts associated with one or more interfaces between different fluids in the borehole;
• and
• responsively displaying a position of at least one of said one or more interfaces.

A system that comprises:

• a tubular string in a borehole, the tubular string having an optical fiber for distributed acoustic sensing (DAS) along the tubular string;
• a DAS measurement unit coupled to the optical fiber to acquire DAS measurements;
• and
• a data processing system coupled to the DAS measurement unit, the data processing system operating on the measurements to detect one or more contrasts in acoustic signatures associated with one or more fluids flowing along a tubing string and to determine position of the one or more acoustic signature contrasts as a function of time.

A system that comprises:

• an optical fiber positioned in a borehole;
• a distributed acoustic sensing (DAS) measurement unit coupled to the optical fiber to acquire DAS measurements;
• and
• a data processing system coupled to the DAS measurement unit, the data processing system operating on the measurements to detect one or more acoustic signature contrasts associated with one or more interfaces between different fluids in the borehole, and to display a position of at least one of said one or more interfaces based on said one or more acoustic signature contrasts.