Monitoring fluid characteristics downhole

A method comprising:

• receiving, by a processing device, sensor signals from an acoustic sensor positioned on a well tool in a wellbore, the sensor signals indicating characteristics of acoustic emissions generated by a well fluid impacting the well tool;
• generating, by the processing device, an acoustic signature for the well fluid using the characteristics of the acoustic emissions;
• determining, by the processing device, a difference between the acoustic signature and a baseline acoustic-signature for the well fluid, the baseline acoustic-signature indicating other characteristics of other acoustic emissions generated by the well fluid;
• determining, by the processing device, a first concentration of sand in the well fluid using the difference between the acoustic signature and the baseline acoustic-signature;
• receiving, by the processing device, a plurality of sensor signals from a motion sensor, the sensor signals indicating amplitudes of vibrations resulting from the well fluid impacting the well tool in a direction perpendicular to the well tool;
• distinguishing, by the processing device, the vibrations from other vibrations resulting from a production fluid flowing in a direction parallel to the well tool by analyzing the plurality of sensor signals;
• generating, by the processing device, a motion signature for the well fluid using amplitudes of the vibrations resulting from the well fluid impacting the well tool in the direction perpendicular to the well tool;
• determining, by the processing device, a difference between the motion signature and a baseline motion-signature associated with the well fluid;
• and
• determining, by the processing device, a second concentration of sand in the well fluid based on the difference between the motion signature and the baseline motion-signature;
• determining, by the processing device, that the first concentration of sand is accurate in response to the first concentration of sand being within a predefined tolerance range of the second concentration of sand;
• and
• transmitting, by the processing device, a notification associated with the first concentration of sand in the well fluid in response to the first concentration of sand exceeding a predefined threshold.

A non-transitory computer-readable medium comprising, program code that is executable by a processing device for causing the processing device to:

• receive sensor signals from an acoustic sensor positioned on a well tool, the sensor signals indicating characteristics of acoustic emissions generated by a well fluid impacting the well tool;
• generate an acoustic signature for the well fluid using the characteristics of the acoustic emissions;
• determine a difference between the acoustic signature a baseline acoustic-signature for the well fluid, the baseline acoustic-signature indicating other amplitudes of other acoustic emissions generated by the well fluid;
• determine a concentration of sand in the well fluid using the difference between the acoustic signature and the baseline acoustic-signature;
• receive a sensor signal from a resistivity sensor, the sensor signal indicating a resistivity of the well fluid;
• determine a ratio of a first component of the well fluid to a second component of the well fluid based on the resistivity of the well fluid;
• determine a viscosity of the well fluid based on the ratio of the first component to the second component;
• and
• determine the concentration of sand in the well fluid using the viscosity of the well fluid;
• and
• transmit a notification associated with the concentration of sand in the well fluid in response to the concentration of sand exceeding a predefined threshold.