分解促进剂对水合物力学的特性影响分析

目的在不同类型的分解促进剂作用下多级降压开采天然气水合物,研究水合物分解的力学性质对储层稳定性的影响。 方法采用不同有效围压、不同分解促进剂及其不同含量、焖井时间等多因素,通过多级降压分解,水合物沉积物储层岩石力学稳定性性能影响效果评价和规律分析。 结果随着降压分解,水合物饱和度降低,抗剪强度和弹性模量逐渐降低,甲烷水合物沉积物呈脆性破坏。 结论分解剂含量越大,对水合物的力学影响越大；注入含量越大,焖井时间越长,水合物强度越低,分解剂对水合物强度减弱的效果越明显；醇类分解剂(乙二醇)比盐类分解剂(CaCl₂)开采水合物更容易减弱水合物试样的强度,降低储层稳定性。 

Influence analysis of decomposition promoter on the mechanical properties of hydrate

ObjectiveThe effect of mechanical properties of hydrate decomposition on reservoir stability was studied by multi-stage depressurization of gas hydrate under the action of different types of decomposition promoters. Methods The effect evaluation and law analysis of rock mechanics stability of hydrate sediment reservoir are carried out by using multiple factors such as different effective confining pressures, different decomposition agents and their concentrations, soaking time, and through multi-level depressurization decomposition. ResultsWith the pressure drops and decomposition, hydrate saturation, shear strength and elastic modulus decrease gradually, and methane hydrate sediments show brittle failure. ConclusionsThe higher the concentration of decomposition agent is, the greater the influence on hydrate mechanics is caused. The higher the injection concentration is, the longer the soak time is, the lower the hydrate strength is, and the more obvious the effect of the decomposition agent on reducing the hydrate strength is. Alcohol decomposition agent (ethylene glycol) is easier to weaken the strength of hydrate samples and to reduce reservoir stability than salt decomposition agent (CaCl₂) during hydrate production.