Investigating Geological Storage Sites of Carbon Dioxide by the Middle-scale Reflection Seismic Method

Chih-Yu Liu

Abstract

The global warming gradually becomes a serious worldwide problem in recent years. It makes a great influence on the Earth’s environment. Due to huge quantities and heat-capacity properties, CO2 is known as the most important factor causing the global warming. How to reduce CO2 has become an urgent subject of the environmental science. The CCS (CO2 Capture and Storage）technology has been developed as a potential method to reduce CO2. It includes the capture, convey and storage of CO2. Three methods to seal up CO2 are proposed: geological sequestration, ocean sequestration and mineral carbonation. Among them, the geological sequestration is mostly feasible.

This paper reports the use of middle-scale reflection seismic method to investigate possible storage sites of CO2. We examine details of the underground structure to evaluate its potential to be a storage site. The seismic source is a ‘Minivibe’ that generates sufficiently powerful and high-frequency signals to map the structure. It is a convenient source to reduce impacts to the environment and to increase the security. The data procession procedures include different kinds of filter, near-surface correction, NMO stack, velocity analysis, and residual static correction. The penetration depth is greater than 3000m and the resolution power is within several tens of meters.

The study area is Taoyuan. The seismic lines are arranged near the coast where new industrial estates are developed and large CO2 is expected to be created that need be treated. The storage places in the same area can reduce the transportation cost. The seismic lines provide great details of the underground structural formations from the Miocene to the Pleistocene ages. All the layers are relatively flat with visible tilt angles, dipping landward. The Chinshui shale is at a depth of 1000m with the thickness about 130m that could be a good candidate as the seal rock. Below this layer, the Nanchuang formation and the Kueichulin formation are between depths of 1000~1700m, that could be good reservoir rocks. Many details including tiny faults and disturbances of structures are available to evaluate the possibility of the area to be a good CO2 storage site.