A forecast of the gas saturation factor in the NB1 layer of Upper Cretaceous deposits within the Nadym-Pur-Taz region of West Siberia

   The investigation of Upper Cretaceous siliceous deposits in West Siberia represents an unconventional problem. The solution to this problem necessitates the utilisation of specialised well logging methods in order to obtain the valuable results. In these circumstances, forecast methods that based on a priori data become important because they allow us to identify high-priority objects for further exploration.   The aim of this research is to make a forecast of the gas saturation factor in the NB1 layer of Upper Cretaceous deposits within the Nadym-Pur-Taz region under conditions of well-data shortage.   The new forecast and mapping method for the volumetric humidity coefficient that based on a priori data is proposed. Consequently, a correlation was identified between the volumetric humidity coefficient and the present depth of deposits. The correlation depends on intensity of silica phase transformation process. The observed dependence is attributed to the tectonic history of the region, specifically the period following the deposition of the NB1 layer siliceous deposits. The gas saturation factor forecast map allows us to identify areas with potential of high gas bearing capacity.