Dynamic positioning method and precision analysis of marine seismic vertical cables

Abstract

AbstractSimilar to conventional ocean bottom seismometers and ocean bottom cables, the attitude and position of vertical cables deployed on the seafloor should be calibrated. However, due to the effect of ocean currents, the cable attitude is not stationary. Therefore, a new method for the dynamic repositioning of vertical cables is required. The dynamic repositioning of the hydrophones on vertical cables plays an important role in accurately describing the structure of the stratum and establishing an accurate velocity model. To realize the dynamic positioning of marine vertical cables, the shot lines are divided according to time, the first break time objective equation is established and the receiver position in each time period is obtained using the inversion methods outlined in this work. By analysing the trace spacing, first break time, shot point coordinate accuracy, temporal resolution, shot line spacing and other factors after repositioning, it is found that the first break time pickup accuracy and shot line spacing are the main factors that affect the repositioning accuracy. Furthermore, the resolution is limited by the timing of a single shot line. Additionally, the trace spacing after repositioning is consistent with the actual situation, which verifies the correctness and feasibility of this method.