In this paper, we propose the framework of risk assessment system for CCS, carbon capture and storage, especially for enhanced recovery of gas, oil and gas hydrates. Based on the protocol proposed by US and European institutions, the framework of enhanced CCS has been modified to improve the functions of geological-based performance assessment. We have developed our original risk assessment system for CCS, regarding the geological features of specific storage sites. Some results on numerical simulation of CO2 migration and the estimation of the leakage of CO2 in pathways are presented and discussed for the further development. In addition, the stimulation of gas hydrates using CO2 would be possible CCS methods at offshore area. The original method of CO2-CH4 substitution in the production of gas hydrates is also introduced in the present study.
The balance of risk and benefit is very important in understanding the feasibility of CO2 geological storage at offshore. A lot of benefits in geological carbon storage, compared with ocean and atmospheric discharge, can be easily understood in the scientific and social aspects of global environment and the economical aspect of CDM. However, the assessment of risks caused by CCS would be hardly undertaken, because of some difficulties in determining the end point and parameters for estimating escape of CO2, effecting ecological and human risks. In order to achieve transparent risk governance for stakeholders who are involved in CCS project, it is necessary to develop the general and/or common framework, enabling it to be fully matured risk communication. In this paper, we propose the framework of risk assessment system for CCS, carbon capture and storage, especially for enhanced recovery of gas, oil and methane hydrates. The framework of enhanced CCS has been modified to improve functions of geological-based performance assessment.