TY JOUR TI Search for extremity zones with discrete mathematical analysis algorithms to identify risks when drilling based on geophysical data KW Discrete mathematical analysis KW density KW geological section KW permafrost KW gas content JO Russian Journal of Earth Sciences AU Bogoutdinov, S.R. AU Odintsova, A.A. AU Pirogova, A.S. PY 2022 IS 22 PB Geophysical Center of the Russian Academy of Sciences