Ninety-nine per cent of methane hydrates were biogenic (formed by microbial activity in the upper several hundred metres of shelf sediment) in origin; about 1 per cent was thermogenic (formed by the breakdown of oily substances at great depths).
99％的沼气水合物都源于生物(由陆架沈降物上层几百米处的微生物活动形成),约1％由热产生(深海油质物资分解而成)。