Potential technical hazards associated with four North American carbon capture and sequestration projects

Abstract

Carbon capture and storage (CCS) risks depend upon the site geology, potential CO 2 -caprock reactions, anthropogenic pathways (legacy wellbores), and well construction and operation. Herein, we assess the major risks, termed 'georisks', acknowledging that quantitative description must be site-specific, although pathway impact generalisations are possible. We discuss geological and pathway issues to guide general site selection practices to reduce georisks. Events that trigger hazards and the consequences are presented for leakage, low storage capacity/injectivity, the release of hazardous gases and materials, surface uplift, and Induced seismicity. A supplementary literature-sourced hazard tabulation was developed with focus on four largescale North American CCS projects (Quest Project, Weyburn Project, Project Pioneer and FutureGen). Each hazard is classified based on the project phase and trigger activity. The risks of CO 2 , brine, or other fluid leakage through wells (injection, monitoring, decommissioned legacy wells) remain uncertain, but legacy well gas leakage is common, rather than exceptional, despite modern cementing and completion practices.

An integrated risk assessment and management framework for carbon capture and storage: a Canadian perspective

“…With respect to technical risk issues in CCS performance and containment, Sarkarfarshi et al (2019) provide an illustrative taxonomy of potential hazards based on international standards and publicly available application and review documents for three North American carbon capture and sequestration projects and one enhanced oil recovery (EOR) project. Six major potential events are described in detail: CO 2 (carbon dioxide), H 2 S (sulphur dioxide) or brine leakage from the reservoir during injection or storage; CO 2 or H 2 S leakage during transportation; release of hazardous gases or materials (other than reservoir and pipeline, e.g., NO 2 (nitrogen dioxide) and PM 2.5 (fine particulate matter) during capture plant operations); surface uplift; induced seismicity; and, unforeseen limitations in site storage capacity or well injectivity.…”

“…Selected hazards associated with integrated CCS projects that could be addressed using a variety of risk management options are given in Table 2 [see Sarkarfarshi et al (2019), for a more complete discussion of CCS hazards]. Developed as the REACT framework for risk management and population health (Krewski et al, 2007;Krewski et al, 2014), risk management options include potential actions in five domains:…”

“…Risk management frameworks for CCS: a global perspective (Larkin et al, 2019d) Canadian context in the present article (Sarkarfarshi et al, 2019) 5…”

Environmental scan and issue awareness: risk management challenges for CCS

“…Another important dimension to this issue is the complexity of the risk assessment for CCS, which is a function of the multi-dimensional aspect of the technology (i.e., the integration of capture, transport, injection and storage). This complexity demands a response in terms of prioritisation of the relative severity of various impact scenarios, especially those which are high-impact, low-probability cases (Larkin et al, 2019c;Sarkarfarshi et al, 2019).…”

Alberta's approach to the transfer of liability for carbon capture and storage projects

“…While the risk of such a release may be low (IPCC, 2005;Larkin et al, 2018b;Haszeldine and Ghaleigh, 2018) much may depend on the characteristics of the individual storage site. Relevant considerations include the existence of natural faults, the characteristics of the geological seals, the tectonic stability of the region and the existence of legacy wells that penetrate the storage complex (Sarkarfarshi et al, 2018;Haszeldine and Ghaleigh, 2018). It is not necessary to assess for present purposes whether the operator's liability for harm suffered by a third party would be strict or faultbased, it is enough to recognise this as a head of potential liability.…”