Carbon Capture and Storage (CCS) is recognised as an important way of reducing the amount of CO 2 added to the atmosphere, and oil and gas reservoirs and saline aquifers are the preferred storage location of most European nations. However, the safety of such storage is dependent on fully exploring the risks of any leakage. The four-year, NERC funded CHIMNEY project is developing better techniques to locate these sub-sea floor structures and determine the permeability of the pathways so that they can be better constrained and quantified.
The chimneys in question are geophysical formations in the sub-seafloor geology, caused by vertical seismic anomalies which resemble chimneys and through which liquids and gases can pass, leaking out from there into the ocean through the sea floor. In August-September 2017, researchers will undertake a major fieldwork programme on a chimney structure in the North Sea, where they will carry out a unique geophysical experiment to determine the internal structure of the chimney. The team will utilise drilled samples of the chimney for analysis to help calibrate the seismic measurements of the chimney structures and determine their permeability. The research trip, aboard the Royal Research Ship (RRS) James Cook, will involve a novel broadband seismic anisotropy experiment over the chimney in order to understand its structure and origin and derive fracture geometry and topology. The project aims to understand the characteristics of the fracture system within the chimney and whether these fractures are open or closed in order to estimate the permeability of the chimney and its surroundings.
The Rock Physics Laboratory at the National Oceanography Centre in Southampton (NOC) will underpin and enhance the interpretation of the data from the seismic anisotropy experiment of the North Sea chimney. Researchers at the laboratory will analyse some of the drilled rock samples and will make and analyse synthetic rock samples with aligned fractures to generate data that may help constrain chimney and surrounding rock permeability. The team also aims to establish accurate fracture density and orientation of the samples. Research teams from the Universities of Southampton and Edinburgh , together with collaborators at the Lawrence Berkeley National Laboratory in California, will use all the data generated by the CHIMNEY project to model the potential CO 2 fluxes and fluid flow through the chimney structures.
Clean Carbon member Professor Jon Bull is the project PI and the team is also working closely with GEOMAR , in Germany and CGG and Applied Acoustics , in the UK. The project is complementary to the EU-funded Horizon 2020 project STEMM-CCS .