In the given paper a three factor decomposition of the field of refracted waves is considered with help of ray-tracing. Due to the fact that the solution obtained on the basis of the mathematical model is unstable, a condition is proposed that regularizes the solution. The possibility of applying the considered mathematical model is demonstrated in case of refraction and buried objects.

In this paper, we investigate optimization algorithm of joint nonlinear AVOA inversion of PP+PS reflections in anisotropic media. Algorithm is based on the exact solution for PP and PS waves reflection coefficients in anisotropic HTI medium. The PP and PS wave’s reflections from the top of the anisotropic layer are examined. We use synthetic seismograms generated by ray method for the algorithm testing. We show that joint compressional and converted wave’s inversion allows increasing the robustness of the method and the accuracy of medium-parameter estimates. Coefficients of anisotropy are determined with better accuracy if signal-to-noise ratio is bigger than 5 for PP wave and bigger than 2 for PS wave.

The search for methane hydrate accumulations has been conducted in the Northern regions of Siberia for more than 50 years. During this time, it failed reliably (with the rise of hydrate-containing core) taken from the borehole to discover any deposits of methane hydrates even in the rocks of the Western Siberian basin, which has been well studied by drilling. On the example of the discovery of two methane hydrates deposits in Canada and China, it is shown that to solve the problem it is necessary to conduct specially organized and technically secured drilling operations on the pre-selected promising areas. For the first time, the parameters of the methane hydrates stability zone in the sedimentary cover of the Vilyuysk syneclise were estimated.

The approach to the formation of sand samples containing methane hydrate of a non-cementing type is studied. The approach is to inject methane-rich water in the sample after formation of methane hydrate by the "excess gas" method. Laboratory research is carried out on a specialized setup that allows to form hydrate -bearing samples and to study their acoustic properties during the experiments. The results are compared with the data of previous experiments on sand samples containing tetrahydrofuran (THF) and methane hydrate formed by the "excess gas" method. It is shown that the studied approach allow to form samples containing methane hydrate of a non-cementing type.