Techbits: Workshop Examines CO2 Capture, Geological Storage

Abstract

Techbits The SPE Applied Technology Workshop (ATW) titled "Capture and Geological Storage of CO2" was held in Perth, Australia, from 7–10 October. Attending the ATW were 107 participants, representing 50 different organizations from 15 countries. The workshop's chief objective was to provide an overview of current CO2 capture and storage (CCS) technology and projects, as well as a look ahead into how technical, economic, and policy developments might facilitate large-scale, widespread application of CCS to mitigate greenhouse-gas (GHG) levels. Cochairpersons Scott Imbus and John Kaldi opened the ATW's initial session with an overview of the goals and expectations for the week, which was followed by the first keynote address, "Carbon Dioxide Capture and Geologic Storage: Research, Development, and Application in Australia," given by Peter J. Cook, chief executive, Cooperative Research Centre for Greenhouse Gas Technologies, which is known as CO2CRC. Cook focused on the role of CO2CRC's Otway basin pilot project in setting a precedent for safe, effective geological storage of CO2 in Australia. The second keynote speaker, John Bradshaw, chief scientist, Geoscience Australia, spoke on "Technical and Regulatory Impacts of Implementing a Geological Storage Regime." Bradshaw reviewed results of the national storage-capacity assessment and the need for a regulatory regime knowledgeable on the trapping and migration properties of CO2 at the large scale. The need for technical rigor to earn public assurance was stressed. The perspectives of energy providers, including oil and gas companies, coal producers, and utilities, formed Session 2. While recognizing that capture technology is commercially available, speakers focused on the large costs that will be borne by the public and industry. Development and demonstration of more-cost-effective capture technology are needed, but funding for demonstration projects is lacking, they agreed. Subsurface aspects of CCS are familiar to the oil and gas industry but not to the public, they pointed out. The risks of CO2 storage can be managed during capture-and-storage operations. However, long-term liability afterward should be dealt with at the public-policy level rather than through the avenue of litigation against the project participants, the speakers noted. Session 3 overviewed technologies and approaches to site assessment. A recurrent theme was balancing information available with that needed to provide suitable models and simulations, as well as the implications of uncertainty. The importance of natural analogs, flexible workflows, and improved, coupled simulations was stressed. Storage assurance was the topic of Session 4. Monitoring programs should be fit-for-purpose, performance-based, and designed to detect and mitigate leakage in the deep subsurface, speakers said. Understanding fault stability through geomechanical studies will help determine whether faults will be vulnerable to CO2 leakage. Well-integrity studies, including assessment protocols, new well-construction design, and materials and intervention options, will be essential to the long-term security of storage sites, speakers said, adding that risk assessment incorporates all technical assurance issues but at present is not "quantitative." By framing CO2 injection, migration, and trapping scenarios, however, the assessment process serves to align stakeholder perception and risk tolerance, speakers noted.