Submarine gas hydrates: methods and results of resource assessment

The article is devoted to the problem of resource assessment of unconventional hydrocarbon - hydrocarbon gas hydrates. The methodological aspects of quantitative resource assessment of submarine gas hydrates of various ranks - global, regional, and local - are considered. An overview of the methods and approaches used for quantitative assessment in the countries with leading gas hydrate resources and their results are presented. Global estimates of methane content in gas hydrates carried out using different methods vary in the range of 2 ∙ 1014 to 7.6 ∙ 1018 m3. The average density of gas hydrate resources per unit area in individual underwater accumulations is estimated at 1.2 ∙ 109 m3/km2. The specific content of hydrate gas in key gas-bearing regions varies significantly, averaging 4.4 ∙ 109 m3/km2. The resource density in these regions is most likely overestimated by two orders. Based on the patterns of reserves density distribution in the series from megaprovince to hydrocarbon deposits, a quantitative assessment of gas hydrates predicted resources in the Russian Arctic seas was carried out. The amount of methane in gas hydrates of the Arctic seas as on 01.01.2020 is estimated at 5.3 to 79.3 trillion m3 with an average of 26.4 trillion m3. It has been established that even the average predicted amount of methane in hydrates increases the initial total free gas resources of the Russian Arctic seas by 28%, and the minimum and maximum - by 6 and 83%, respectively this fact confirms the considerable resource potential of submarine gas hydrates