Abstract: The commonly used thermodynamic inhibitors in industry have issues such as large usage amounts,high costs,and severe pollution.To address such issues,based on the principle of synergistic inhibition by the combination of thermodynamic and kinetic inhibitors,the effectiveness and variation patterns of the methanol and polyvinylpyrrolidone (PVP) compound system in inhibiting hydrate formation were studied.The study shows that Methanol molecules inhibit hydrate formation through their hydrophilic hydroxyl groups and lipophilic methyl groups.The amount of hydrate formed decreases and may even disappear with increasing methanol usage,with the optimal inhibitory effect of methanol on hydrate formation achieved at a mass fraction of 10.00%.PVP inhibits hydrate nucleation and growth through internal dissolution and surface adsorption.The effectiveness of PVP in inhibiting hydrate formation is determined jointly by its relative molecular mass and mole fraction,and there exists an optimal mass fraction for the best inhibitory effect.Within a certain range,in inhibitor solutions with the same mole fraction,the inhibitory performance of PVP against hydrate formation increases with increasing relative molecular mass.The compound system of PVP and methanol is more effective in inhibiting hydrate formation than using methanol alone at the same mass fraction,demonstrating good synergistic inhibitory performance.The combined use of different types of inhibitors can both reduce costs and enhance the effectiveness of inhibiting hydrate formation,ensuring the safe production of gas wells.

Key words: methane hydrate, methanol, polyvinylpyrrolidone, synergistic inhibition principle, field application