Abstract:

In marine seismic exploration, the severe seabed undulation and velocity difference have great influence on the kinematic and dynamic characteristics of reflected waves in the underlying strata. In this paper, submarine steep slope model, submarine depression model, submarine uplift model and submarine volcano model are established for the rugged seabed, and the effects of rugged seabed on the reflection wave characteristics of the underlying horizontal strata are studied by the optimized eight-order finite difference method and the optimized four-order Runge-Kutt (RK) method under the staggered grid simulation. Numerical examples show that submarine steep slope, submarine depression and submarine uplift not only distort the reflected waves and converted waves of the underlying horizontal strata, but also affect the energy distribution of the reflected waves, thus easily causing the structural illusion. Submarine volcano causes more complex distortion of reflected and converted waves from the underlying horizontal strata, which brings difficulties to the data processing and interpretation in marine seismic exploration.

Key words: rugged seabed, staggered grid, optimized finite difference method, optimized RK method, characteristics of reflection waves