Seismic Reflection Survey to Allocate 3000m Deep Target Formation in s Preferred Carbon Sequestration Site

Abstract

Taiwan Power Company (TPC) launched the CCS pilot project in 2008. In the investigation stage, the Chang-Gong site was selected as the preferred site for the suitable geology condition and large storage capacity. Under the Chang- Gong preferred site, target aquifer underlying the recent overburden sediments consists of four key geologic formations, namely KCL, CS, CL, and TKS formations from bottom to top. These formations have been outlined based on extensive literal review and analysis of available geological data, the maximum depth is estimated approximately 3,000 m. Hence, prior to allocate a 3,000 m deep characterization well, the land seismic reflection survey is regarded as compulsory to testify the adequacy of required drilling depth. Six survey lines were distributed in the industrial park of the preferred site, the seismic data showed higher S/N ratio than expected. It may be due to the fact that only few human activities and rather low background noises of the preferred test site. The continuous operation of wind-power generator, ocean current and tidal wave resulted in no significant effects on the seismic data. Moreover, the saturated soil would also help the downward penetration of source energy with mini-vibe. For better interpretation of the seismic profiles, an auxiliary seismic survey had been conducted nearby a pre-existing deep well (WG-1) located 15 km away and south of the industrial park. The auxiliary seismic profile showed four extinct reflectors which match in sequence with the formation boundaries as revealed with the well log of the WG-1. The six seismic profiles obtained also showed four extinct reflectors, which correlated consistency with the profile obtained 15 km away. This seismic investigation showed the top of the target formations was in depth ranged from 2,200 m to 2,460 m. Based on the depth interpretation of the target geological formations, a preliminary planning on the drilling depth, well bore development scheme, and stability design can be done prior to allocate a 3000 m characterization well on-site.