Numerical Modeling with a Grid-Characteristic Method of Elastic Wave Propagation in Geological Media with Gas Cavities

Abstract

Shallow gas in ground water geological layers is of great danger for drilling rigs in the case of accidental opening of gas deposits. The gas may rise towards the water surface, and its emission into the atmosphere may threaten the environment. It is very important to forecast the gas emissions in order to prevent catastrophic destruction of drilling rigs and loss of human lives. This paper presents the results of numerical simulations of seismic wave propagation towards the water surface in models with gas deposits in a layered soil for the 3D case. The modeling is carried out for a 4-year period for layers located at a depth of 1000 m from the sea bottom. The calculation results (wave patterns and seismograms) show that the gas may approach the water surface in the 4th year of the calculations. The results for a 3D problem are in agreement with those for a 2D problem obtained by the authors earlier. This is very important, since the calculations can be greatly simplified.