Sector SM.1 – Carbon Capture (Usage) and Storage (Aquifer, Cushion Gas, EOR, EGR)
It is now established that one of the options to mitigate for Climate Change and enter into the New Era of Sustainable Energy Mix is the Capture of Carbon of CO2 at the source, and the successive underground Storage in depleted Oil and Gas Reservoirs, in saline Aquifers, or in Coal layers that were previously mined. Several experiments have already been conducted in the past with variable success. The CCUS, instead, Carbon Capture, Usage and Storage, has been applied since decades in the United States in EOR (Enhanced Oil Recovery) projects, where the CO2 is used to boost up the production in older Oil and Gas reservoirs, as an alternative to water or steam injection.
First of all, we need to understand where the CO2 comes from and how it can be captured, using various filters. At present, CO2 is generated through the burning of conventional sources such as Coal, Oil and Gas, for electricity generation, heating, and transport in the Public sector, and mostly in Refineries and in the Steel and Cement Industry in the Private sector. The CO2 can be captured with special filters and needs to be purified before transporting it for underground storage. Obviously in the evaluation of transport what needs to be considered is the distance between the source and the site were storage can be conducted, and the type of transport needed (pipelines, rail, shipping, trucking, etc.). This obviously calls for enormous steps in the development of technology, logistics, engineering and legislation. But the involved costs can be leveraged by using the CO2 as Cushion Gas for Gas storage fields, or for Enhanced Oil or Gas recovery from brown fields (EOR/EGR).
Another solution which is being studied, revolutionary as it may sound, is Direct Air Capture (DAC) of CO2 using special membranes (a process now still involving considerable energy consumption), which would avoid the transport problems, but would not mitigate directly for the CO2 producing facilities.
Studying the geo-sites for storage potential evaluation, and their additional potential for applying Cushion Gas or EOR/EGR, is the among the main CCS task OCRE believes Geoscientists needs to be massively involved in, to evaluate all the options applying decades of G&G experience in the field of analysing and modelling subsurface reservoirs of all types, and our worldwide experts Network of Excellency is already working on various options and projects.
The complete Carbon Capture and Storage Flow Chart. From: van Dijk (2012).