Leakage Risk Evaluation Model for Single Wells of CO2: A case study

Abstract

ABSTRACT From the experience of CO2 storage in the past, the leakage part of CO2 may be the wellbore, fractures, faults, and cap rocks in the formation. Once CO2 leaks from the wellbore, it will pose a serious threat to the life safety of workers near the well pad in a short time. Therefore, from the perspective of single well leakage in the process of CO2 storage, this paper studies the risk of single well CO2 injection leakage in Changqing Oilfield, Ordos Basin, simulates CO2 leakage from the wellbore, and simulates it with the diffusion model after toxic gas leakage, so as to obtain the CO2 concentration at different distances from the leakage point. The range of affected area after CO2 leakage is determined by the critical value of CO2 leakage diffusion concentration. According to the calculation in this paper, the area near the leakage source is divided into (taking summer as an example: the wind speed is about 3.3 m/s): fatal area (2.2 m), serious injury area (4.3 m), inhalation reaction region (19.5 m) and safety area (> 50 m). The leakage risk of CO2 injection buried wellbore in low-permeability reservoir in Ordos Basin is evaluated.