In this study, the integral theory together with: Boussinesq approximation are applied to formulate a bubble plume model which simulates the hydrodynamic behaviors of offshore gas well blowouts under seawater. The numerical simulation results are good in comparison with field data of Fannelop and Sjoen (1980). The plume radius, centerline upward velocity and buoyancy for different ambient fluid stratification and gas flow rate cases are calculated and investigated. Analysis of the calculated results reveal that:
Blowout with small gas flow rate will have large plume radius but smaller plume velocity, buoyancy, and terminal rise height;
Ambient sea water with strong density stratification will inhibit the bubble plume rise and get a lower terminal rise height;
When the stratification becomes very large, the terminal rise height varies slightly even increases gas flow rate in several orders of magnitude.
When offshore underwater gas-well blows out, they will be harmful to marine life due to the gas-containing hydrocarbon. The damage region is strongly dependent on the gas rising straight to the water surface and spreading out horizontally. So it stimulates the study on the hydrodynamics of the gas blowouts which will be helpful to understand and predict the extent of the damage. As a continuous stream of gas is injected into the interior of a liquid, the gas takes the form of bubbles which rises up owing to buoyancy and which impart an upward velocity to the surrounding liquid. The behavior of the continuous source of gas bubble can be treated as a bubble plume. Generally speaking, a bubble plume is different from a plume driven by a normal source of buoyancy in some respects. Such as: the volume flow rate of gas will increase with height; the bubbles will rise faster than the liquid.
