Theoretical assessment of CO2 injection into low-temperature water zones for non-leaking storage in hydrate form

Abstract

Concerns exist about CO2 leaks from conventional supercritical CO2 storage reservoirs. This study investigates injecting CO2 into low-temperature offshore reservoirs to lock it in a solid state, thus preventing potential leaks. An analytical model was developed to predict CO2 injectivity into frac-packed injection wells in these low-temperature reservoirs. While the initial transient flow model was complex with Bessel functions and exponential integral, it was further simplified for practical field application. Sensitivity analysis of the model reveals that injectivity is less sensitive to reservoir permeability but more sensitive to fracture conductivity. The analytical model suggests injectivity is directly proportional to fracture width and fracture permeability. The case study utilizing field data from the South China Sea indicates feasible injection rates ranging from 6 to 17 tons/day depending on fracture conductivity. This work provides an analytical tool to predict injectivity for CO2 storage in frac-packed low-temperature offshore reservoirs, contributing to carbon reduction and neutralization goals. Document Type: Short communication Cited as: Guo, B., Zhang, P. Theoretical assessment of CO2 injection into low-temperature water zones for non-leaking storage in hydrate form. Advances in Geo-Energy Research, 2023, 10(1): 1-6. https://doi.org/10.46690/ager.2023.10.01