Real-time monitoring and evaluation of fractures is one of the core issues in the multi-stage fracturing process of horizontal wells

and has long been a focus of many scholars. During the fracturing construction

the pressure during pump shutdown includes water hammer pressure and seepage pressure. By installing a high-frequency pressure device at the wellhead

not only the pump shutdown pressure drop curve but also the water hammer waveform curve can be completely collected. In this paper

the simulated pressure data are obtained by numerically solving the governing equation of wellbore water hammer. The cepstrum analysis of the simulated water hammer pressure verifies that the pressure generated by the water hammer has convolution characteristics. According to the related theory of wave impedance and cepstrum analysis

the water hammer wave can be used to determine the number of fracture clusters and the depth in multi-cluster fracturing of horizontal wells. The field application in Sichuan shale gas well shows that this method can find five liquid inlet points

of which the inversion results of four liquid inlet points are close to four perforation positions

and the remaining four clusters of holes in the design correspond to the liquid inlet points It was not detected in the cepstrum analysis.