NMR based experiment of fluid invasion to natural gas hydrate reservoir and hydrate dissociation inhibition mechanism

•An NMR-based method of hydrate dissociation during fluid invasion is presented.•Invasion fluid saturation is reduced from 80 % to 30 % by dissociation inhibition.•Mechanism of hydrate dissociation inhibitor is analyzed experimentally.•Dissociation inhibitor reduces the heat and mass transfer ability of drilling fluid.