We apply tube-wave monitoring method to a time-lapse cross-well dataset from Mallik field. Raw waveforms are used for analysis thus avoiding any smearing of 4D response introduced by pre-processing. We perform extensive modeling that includes effects of a source borehole and confirms nature of most prominent arrivals as being tube-wave related. Modeling proves that strongest conversion of tube wave into P and S waves occurs at the sharp acoustic boundary. Data displays clear time-lapse changes in tube-wave related arrivals, while shows no change in first arrivals. Modeling suggests that to explain the data the reservoir changes have to occur at a deeper interval than previously anticipated, below the perforations. Excellent agreement between modeled and experimental data provides us with good confidence in our results. This study represents first application of tube-wave monitoring concept.