Ignition Range of Natural Gas Well Blowout and Its Heat Radiation Effect on Circumjacent Facilities

In the process of natural gas exploration and development, the well blowout will lead to serious consequences. Among the damage forms, the heat radiation from the natural gas fire flame can threat the onsite and surrounding workers as well as the facilities dramatically. With a practical natural gas well exploration project as an example, using a Computational Fluid Dynamics (CFD) software, the flux field is simulated with well pressures of 10, 20 and 30MPa. In this study, 3 different air velocities and 2 well diameters (63.5 and 88.5mm) are considered in the well blowout and eighteen groups of simulation results are obtained. The simulation results, as well as the heat radiation effects on the circumjacent facilities, are analyzed. It is indicated that both the well pressure and diameter have little influence on the blowout gas velocity with other parameters fixed. With the same well pressure and diameter, the greater the air velocity is, the lower and smaller the effective ignition area will be. Under the simulation conditions, the gas ejection velocity is about 400m/s and the surface temperature of the natural gas flame exceeds 1500K. For the facilities, the damage diameter of the project fire is about 40m; meanwhile the injury diameter of the project fire for human beings is about 104m.