Chinese Academy of Sciences

Guangjun Guo

Yongyou Yang

Changqian Cao

Shuangchi Liu

A magnetofluid enhanced electromagnetic heating device and method for preventing and treating secondary hydrates around a well are provided. When exploiting natural gas hydrates by depressurization, secondary hydrates or ice can form due to the decreasing temperature around the well, so that gas migration in sediment is blocked, and the gas production is reduced. According to this disclosure, a coil is arranged outside a casing pipe to generate an alternating electromagnetic field radiated to sediment. As a result, magnetite nanoparticles naturally contained in the sediment generate magnetothermal effect to heat the sediment. Additionally, the magnetofluid containing the ferromagnetic nanoparticles can be injected together with fracturing fluid during hydraulic fracturing of the reservoir, so that the magnetothermal effect of the sediment is further enhanced. Thus, secondary hydrates or ice can be prevented from forming around the well so that the exploitation efficiency of natural gas hydrates is improved.

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Beijing, China

Guangjun Guo