title: Modeling the key factors that could influence the diffusion of CO2from a wellbore blowout in the Ordos Basin, China.
abstract: Carbon dioxide (CO2) blowout from a wellbore is regarded as a potential environment risk of a CO2capture and storage (CCS) project. In this paper, an assumed blowout of a wellbore was examined for China's Shenhua CCS demonstration project. The significant factors that influenced the diffusion of CO2were identified by using a response surface method with the Box-Behnken experiment design. The numerical simulations showed that the mass emission rate of CO2from the source and the ambient wind speed have significant influence on the area of interest (the area of high CO2concentration above 30,000 ppm). There is a strong positive correlation between the mass emission rate and the area of interest, but there is a strong negative correlation between the ambient wind speed and the area of interest. Several other variables have very little influence on the area of interest, e.g., the temperature of CO2, ambient temperature, relative humidity, and stability class values. Due to the weather conditions at the Shenhua CCS demonstration site at the time of the modeled CO2blowout, the largest diffusion distance of CO2in the downwind direction did not exceed 200 m along the centerline. When the ambient wind speed is in the range of 0.1-2.0 m/s and the mass emission rate is in the range of 60-120 kg/s, the range of the diffusion of CO2is at the most dangerous level (i.e., almost all Grade Four marks in the risk matrix). Therefore, if the injection of CO2takes place in a region that has relatively low perennial wind speed, special attention should be paid to the formulation of pre-planned, emergency measures in case there is a leakage accident. The proposed risk matrix that classifies and grades blowout risks can be used as a reference for the development of appropriate regulations. This work may offer some indicators in developing risk profiles and emergency responses for CO2blowouts.
authors.affiliation: State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, China. qli@whrsm.ac.cn.
authors.forename: Qi
authors.identifier: http://orcid.org/0000-0003-0679-4385
authors.initials: Q
authors.lastname: Li
authors.affiliation: State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Shi
authors.affiliation: Institute of Crustal Dynamics, China Earthquake Administration, Beijing, 100085, China.
authors.forename: Duoxing
authors.initials: D
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Xiaochen
authors.initials: X
authors.lastname: Wei
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002245:Carbon Dioxide / Q000032:analysis*; D002681:China; D004058:Diffusion; D004784:Environmental Monitoring / Q000379:methods; D014919:Wind
chemical_list: D000393:Air Pollutants; D002245:Carbon Dioxide
keywords: CO2 capture and storage (CCS); CO2 diffusion; Environmental risk assessment; Risk matrix; Uncertainty analysis; Wellbore leakage