P-S travel time detection of low SNR induced seismicity based on time-domain particle motion

Abstract

Induced seismicity provides insights from subsurface reservoirs. By detecting the P-S travel time of induced seismicity, we can locate the source of the seismic activity, which can obtain the fracture mapping and the shape of the stimulated reservoir volume. After our previous study of P-wave arrival detection for low signal to noise ratio SNR events, this study aims to detect the associated S-wave and the P-S travel time. 3D particle motion analysis is introduced to detect the S-wave arrival of low SNR events. The S-wave arrival is evaluated from two aspects: planarity and perpendicularity. Eigendecomposition is performed on a matrix constructed by the three-component time-domain data. For more comprehensive detection of low SNR events, these two features are combined to constitute the characteristic function. The S-wave arrival time can be detected by setting the thresholds on the characteristic functions and further detecting the P-S travel time. The proposed method is applied to field data recorded at the Groningen field in the Netherlands to detect known catalog events as well as low SNR events. The P-S travel time results obtained by the proposed method are compared with STA/LTA, and the proposed method is more sensitive to low SNR events. The proposed detection method can yield similar results instead of extracting the P- and S-wave arrivals exactly to obtain the P-S travel time as the normal method.