Читать книгу Distributed Acoustic Sensing in Geophysics - Группа авторов - Страница 65

The field test data have proved that the DMOF‐based fiber optic DAS system can successfully acquire borehole seismic data with good quality. Through the deployment of the DMOF cable in a well as the sensing device, which is connected to the interrogator of the DAS system at surface, the seismic signals can be recorded along the full length of the well for each shot. A longer duration is not required for rigging up and down the conventional borehole geophone array; hence, the survey efficiency is significantly improved. Moreover, the DMOF‐DAS system offers the opportunity to achieve a much higher spatial resolution (typically of 2 m) and lower cost than current technologies. In addition, the coupling method is very important for the VSP survey. For the water‐injection coupling scheme, the tube wave will be the main noise. The cementation method will provide the strongest coupling, resulting in better VSP data with a higher SNR.