Velocity Model Calibration Based on Distributed Acoustic Sensing Perforation Data

Reservoir monitory technology based on Distributed Acoustic Sensing (DAS) technology provides a new means to characterize and monitor the underground structure, so as to achieve rapid and real-time monitoring and identification of underground target structure changes, which has been widely used in hydraulic fracturing micro-seismic monitoring and precision engineering monitoring. When micro-seismic monitoring technology is used for source location imaging, it is necessary to consider the influence of many factors on the location results, among which the velocity model error is one of the most important factors, so it is a key step to correct the initial velocity model to obtain an accurate velocity model. On the basis of receiving the arrival time data of the perforating source by the distributed optical fiber sensing, the underground horizon is divided according to the acoustic logging curve, the micro-seismic velocity model is corrected by using the perforation event, the travel-time relationship formula based on the velocity model and the propagation path is studied, and a more accurate velocity model is further solved and corrected by the particle swarm optimizatio (PSO) in the global optimization method. The accuracy of the method was validated through numerical simulations, which demonstrated small calibration errors that were almost uniformly below 3%. The method was subsequently applied to real DAS perforation data, achieving satisfactory inversion results.