Revolutionizing Downhole Monitoring: An Acoustic Waveguide Approach for Wireless Power and Communication

Abstract

Wireless power and communication for downhole sensors is a promising approach to enable long-term monitoring of subsurface environments without the need for intrusive wiring. This work presents the design, construction, and evaluation of a prototype system that uses well casing as an acoustic waveguide to transmit low-frequency acoustic energy from the surface to downhole sensors, enabling wireless power harvesting and acoustic telemetry. A 1000-foot test bed simulating realistic wellbore conditions, including cemented annulus and formation materials, was constructed to evaluate system performance. Initial testing showed the system could harvest acoustic energy and transmit sensor data acoustically. However, changes in formation saturation increased acoustic attenuation, limiting power transfer and delaying full system testing in the test bed. To address this, the prototype was tested in a laboratory setup using a short section of pipe replicating key test bed features. These tests confirmed that power harvesting is feasible, though the current power consumption of the tool limits sustained autonomous operation. Acoustic communication was demonstrated with modest power requirements. These results provide insights into the challenges and potential of wireless acoustic power and communication through well casing, informing future development toward practical downhole monitoring solutions that could serve as alternatives to conventional Permanent Downhole Gauge systems.