5:15 PM - 7:15 PM
[STT42-P05] Simulation to examine the effectiveness of optical hybrid submarine cable systems
Keywords:CCS, DAS, Optical hybrid system
Here, the optical hybrid method is defined as a system that combines an optical interferometry three-component accelerometer and a distributed acoustic sensing (DAS: a distributed acoustic sensor that uses optical fiber cables as sensors). This type of system does not use electronic components in the sensor section, so it has high environmental resistance to temperature and other factors, and can be used to construct a highly reliable observation system. Furthermore, compared to OBS (Ocean Bottom Seismometer) and OBN (Ocean Bottom Node), it has the characteristic of providing data in real time.
In CCS (Carbon Capture Storage), in order to ensure that CO2 is stored stably, it is expected that regular and continuous monitoring, that is, grasping the development state of the CO2 plume and the presence or absence of leakage, and risk diagnosis of induced earthquakes by real-time microearthquake observation, will be required.
Monitoring using the optical hybrid method can obtain high-density data in real time, and it is thought that it can be designed to meet the requirements for CCS monitoring. It is also possible to reduce the number of costly 3D seismic surveys, which are the mainstream for underground structure monitoring, and it is expected to lead to reduced monitoring costs.
In this presentation, we will show the results of a simulation of the detection capability of microseismics and the accuracy of determining the microseismic source location to demonstrate the usefulness of the optical hybrid submarine cable. The magnitude of the microseismics that can be detected by this system was calculated using the formula of Watanabe (1971) and the correction formula of Ide (2002), taking into account the expected amplitude of the DAS. The simulation of the microseismic source location accuracy was performed by first setting multiple patterns of microseismic source locations and receiver point arrangements in GMS, an elastic wave simulation software released by the National Research Institute for Earth Science and Disaster Resilience, and creating simulated waveform data that reflects the properties of the DAS for the output waveform data. Next, the microseismic source was determined using this waveform data, and the accuracy was evaluated with and without the DAS.
This research was conducted with the support of a grant from the Nippon Foundation-DeepStar Joint Ocean Innovation R&D Program (Project name: Development of a permanently installed CCS reservoir monitoring system using an optical hybrid submarine cable). We would like to express our sincere gratitude.
In CCS (Carbon Capture Storage), in order to ensure that CO2 is stored stably, it is expected that regular and continuous monitoring, that is, grasping the development state of the CO2 plume and the presence or absence of leakage, and risk diagnosis of induced earthquakes by real-time microearthquake observation, will be required.
Monitoring using the optical hybrid method can obtain high-density data in real time, and it is thought that it can be designed to meet the requirements for CCS monitoring. It is also possible to reduce the number of costly 3D seismic surveys, which are the mainstream for underground structure monitoring, and it is expected to lead to reduced monitoring costs.
In this presentation, we will show the results of a simulation of the detection capability of microseismics and the accuracy of determining the microseismic source location to demonstrate the usefulness of the optical hybrid submarine cable. The magnitude of the microseismics that can be detected by this system was calculated using the formula of Watanabe (1971) and the correction formula of Ide (2002), taking into account the expected amplitude of the DAS. The simulation of the microseismic source location accuracy was performed by first setting multiple patterns of microseismic source locations and receiver point arrangements in GMS, an elastic wave simulation software released by the National Research Institute for Earth Science and Disaster Resilience, and creating simulated waveform data that reflects the properties of the DAS for the output waveform data. Next, the microseismic source was determined using this waveform data, and the accuracy was evaluated with and without the DAS.
This research was conducted with the support of a grant from the Nippon Foundation-DeepStar Joint Ocean Innovation R&D Program (Project name: Development of a permanently installed CCS reservoir monitoring system using an optical hybrid submarine cable). We would like to express our sincere gratitude.