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在海底天然气渗漏系统沉淀水合物的动力学基础上,建立了水合物沉淀与分解的化学动力学模型。应用该模型分析了美国墨西哥湾布什山天然气渗漏系统水合物的成藏过程,探讨了水合物沉淀、稳定性影响因素。在渗漏通量为每年400kg·m-2的单个通道中,约需425a才能导致水合物稳定带沉积层约30%孔隙完全被水合物充填,渗漏通道被堵塞,沉淀的水合物在剖面上从稳定带底部向海底趋于富C3+C4。在渗漏通道天然气流量由弱到强再到弱的演化过程中,渗漏速度增大过程中形成的水合物在渗漏速度减小过程中将分解,总量约10%的水合物将被分解。如果分解产生的天然气可快速迁移出渗漏系统,海底温度的升高可引起约40%的水合物在20d内分解,并导致海底渗漏速度的急剧增大。
Based on the kinetics of hydrate precipitation in the natural gas leakage system, a chemical kinetic model of hydrate precipitation and decomposition was established. The model was used to analyze the hydrocarbon accumulation process of the gas leakage system in the Bushush Mountains in the Gulf of Mexico, and the influencing factors on the hydrate precipitation and stability were discussed. In a single pass with a permeation flux of 400 kg · m -2 per year, it takes about 425 a to cause a hydrate to stabilize. About 30% of the sediment in the sediment is completely filled with hydrate and the leak channel is blocked. The precipitated hydrate, From the bottom of the stable zone to the seafloor tends to be rich in C3 + C4. Hydrates formed during the increase of seepage velocity will decompose in the process of decreasing the leakage rate during the course of gas flow from weak to strong to weak in the seepage channel. The hydrates in the total amount of about 10% will be decomposed break down. If the gas produced by the decomposition can rapidly migrate out of the leaking system, the increase of the seafloor temperature can cause about 40% of the hydrate to decompose in 20 days and lead to a drastic increase of the seabed leakage rate.