To achieve dynamic risk management and control during the CO2 injection process in CCUS oilfields and prevent CO2 leakage acidents, a dynamic assessment method for the probability of high-risk scenarios was proposed. Firstly, a novel improved FPN model was developed by integrating a three-parameter Weibull distribution model for equipment failure probability based on Grey Model (GM) and Support Vector Machine (SVM) with FPN model. Subsequently, the risk analysis was conducted on the above ground CO2 injection system of CCUS process. The CO2 leakage accident chain was established to quantitatively predict the accident occurrence probability. The dynamic characteristic of equipment failure probability changing with time (t) and the impact of protection layers on risk were taken into account by the improved FPN. The results indicate that when t=500 h, the risk exhibits an exponential increase. The safety valve is identified as the protection layer with the highest importance. When t=303 days, the system's residual risk reaches the PetroChina risk acceptance criterion of 1×10-5, indicating that the system risk becomes unacceptable beyond this point. It is recommended to add a high-high level interlock protection layer, which extends the time until system risk becomes unacceptable to 5 832 days, thereby significantly reducing maintenance frequency and costs.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |