Evaluating Technical Feasibility of Gigaton Scale CO2 Storage using Produced Water Disposal Data in US Gulf Coast

Based on the scenarios proposed in the 2018 IPCC Special Report, about 5 Gt of CO2 per year should be mitigated using carbon capture and storage to limit increase in global temperature to 1.5°C. Current global geologic CO2 storage is about 40 Mt/yr and data from these existing projects do not adequately demonstrate CO2 storage feasibility at the scale of gigatons per year. In this study, we investigate gigaton-scale geologic CO2 storage feasibility using data from thousands of produced water disposal wells in the U.S. To evaluate gigaton-scale geologic CO2 storage feasibility, we investigate three main questions: (i) Is it technically feasible to inject gigatons of CO2 every year in the subsurface? (ii) How many wells are needed to inject a gigaton of CO2? (iii) What is the expected increase in pressure in subsurface when such a large amount of CO2 is injected? For this study, data from produced water disposal wells in the onshore region of the Texas Gulf Coast and Louisiana are analyzed. The data analysis shows that both at the national scale and the Gulf Coast regional scale, it is technically feasible to store gigatons of CO2 per year. Produced water injection wells with injection rates equivalent to 1 MtCO2/yr already exist, and with such rates, relatively few wells are needed to reach the 1 GtCO2 per year goal. Finally, we can expect low pressure buildup even for high-rate injection wells in suitable storage/disposal formations. In summary, this study provides a detailed analysis of produced water data and implications for gigaton-scale CO2 storage.