The numerical modeling of the elastic waves propagation in the geological media with gas cavities using the grid-characteristic method

The shallow gas in the ground geological layers of the water space is of great danger for the drilling rigs in the case of an accident opening of the gas deposits. Gas starts rising towards the surface of water, and sooner or later, the gas emission into the atmosphere threatens the environment. It is very important to be able to forecast the gas emissions in order to prevent the catastrophic consequences with the destruction of drilling rigs and people fatalities.
This paper presents the results for the numerical modeling of seismic waves propagation in models with gas deposits through the layered soil towards the surface of water for the 3D case. The modeling was carried out for the 4-year period for the layers, which are located at the depth of 1000 m from the bottom of the sea. The results of the computations (the wave pictures and seismograms) show the approach of gas to the surface of water for the 4th year of the computations. The consistency of the results for the 3D problem with the results for the 2D problem, early obtained by the authors, is very important for the further research into the area in question.