Carbon utilization and storage through rehabilitation of groundwater wells

According to the Intergovernmental Panel on Climate Change (IPCC) of the United Nations (UN), rise in atmospheric concentration of carbon dioxide (CO2) due to anthropogenic factors is considered as the primary driver for global climate change. With almost every major corporation around the world working towards their "net-zero goals", it is becoming increasingly important to have more technologies that can help reduce carbon footprint. Achieving sequestration of CO2 in the subsurface through Carbon Capture Utilization and Storage (CCUS) technologies like CO2-Enhanced Oil Recovery, CO2-Enhanced Geothermal Systems, CO2-Enhanced Coal Bed Methane, etc. is well accepted. We introduce yet another attractive CCUS opportunity through well rehabilitation. Aqua Freed (R) and Aqua Gard (R) are well-known well rehabilitation and preventive well maintenance technologies that utilize (inject underground) liquid CO2 for the purpose. The goal of this study was to quantify the storage capacity of Aqua Freed (R) and Aqua Gard (R), and establish their CCUS credentials. Depending on the well being serviced, these technologies can inject up to 40 US tons of CO2 per well. Based on field data collection and statistical modeling, we estimated that 82-96% (median 90%) of the injected CO2 remains in the subsurface post injection. Overall, our results and analysis of the US market suggest that using CO2 for well rehabilitation and maintenance has a storage potential of several megatonnes of CO2 annually in the US alone.