Blowout is one of the most serious accidents of gas wells during drilling. To investigate leakage and dispersion of gas blowout and to provide scientific guidance for on-site emergency response, it is necessary to identify what model should be used to describe the leakage source. Leakage source model of gas blowout was theoretically analyzed by fluid dynamics and aerodynamics, and was also numerically demonstrated by computational fluid dynamics. Distributions of temperature, static pressure and Mach number were obtained from simulation based on theoretical analysis. These numerical results agree well with both theoretical results and related experimental results done by other researchers. The present study shows that leakage source of gas blowout during drilling stage can be characterized by model of choked flow and gas blowout can be recognized as under-expanded jet flow.
| 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 |