The acoustic-wave-detection system is considered a nondestructive monitoring system to estimate distances by measuring the time-of-flight of an ultrasonic wave. In this paper, a comprehensive experimental study was conducted to investigate the feasibility of the acoustic-wave-detection system in monitoring the shape and position of the gas phase in the vapour-extraction (VAPEX) process. For this purpose, various stages of vapour-chamber evolution in the VAPEX process were simulated experimentally by changing the shape of air balloons buried in simulated porous media in a laboratory-scale model. Then, an array of ultrasound transducers and receivers was used to measure time of flight at different stages of the vapour-chamber growth. Finally, the collected data were fed into a signal-processing program developed in this study to determine the shape of the vapour chamber. Conducted analysis in this study includes sound-speed testing in different porous media, signal-attenuation tests in different porous media, imaging of different simulated vapour chambers in different porous media, and acquisition and analysis experiments. Results show that acoustic-wave detection can be used for accurate mapping of the position and shape of the vapour chamber in the studied process. Monitoring the shape and growth of the vapour chamber provides valuable information for optimizing oil production in order to maximize oil recovery. The proposed methodology is able to identify acoustic anomalies in a porous medium in the laboratory.