固定式震源ACROSSを活用したDAS-VSP方式による貯留層モニタリングシステムの実証試験成果と今後の展望

<p>This paper focuses on a high accuracy permanent reservoir monitoring system that integrates a permanent seismic source named accurately controlled routinely operated signal system（ACROSS）and a fiber optic sensing technology called distributed acoustic sensing（DAS）. To evaluate the effectiveness and benefits of this system, we have conducted a DAS-VSP data acquisition demonstration test at the Aquistore CO₂ storage site in Saskatchewan, Canada. We have acquired four monitoring data sets in this field since 2016 when ACROSS was moved to a location about 750 m away from the observation well. During data acquisition, ACROSS was remotely controlled from Japan to reduce the HSE risk and cost. We constructed an efficient data processing flow including ACROSS signal processing, data matching, VSP data processing and 4D noise suppression. A 4D response evaluation method was established using two different types of repeatability indexes. The data acquisition, processing and evaluation were successful and a high- repeatability seismic section was obtained. In addition, we performed advanced data acquisition using a wireline DAS method and data processing using reverse time migration（RTM）. Lastly, we compared the latest data processing results with 3D seismic monitoring results acquired in the same time and discussed future prospects of reservoir monitoring in a CCUS and EOR field. We think that our monitoring system will be implemented as a useful reservoir monitoring system, so we plan to continue associated research, including the preparation for the new data acquisition in 2022.</p>