Method for electric heating assisted depressurizing production of natural gas hydrate reservoir through dual horizontal shafts

Abstract

The invention discloses a method for electric heating assisted depressurizing production of a natural gas hydrate reservoir through dual horizontal shafts. Electrodes are installed on the upper horizontal shaft and the lower horizontal shaft correspondingly, the natural gas hydrate reservoir serves as a resistor, electric energy is directly converted into heat energy for mining natural gas hydrate, and electric heating mining is carried out on the natural gas hydrate reservoir accordingly. Specifically, the method includes the steps that the electrodes are installed at the horizontal section of the upper horizontal shaft and the horizontal section of the lower horizontal shaft correspondingly, and the electrodes are connected with a ground control cabinet through cables; the upper horizontal shaft and the lower horizontal shaft form a current loop through water obtained through decomposition of the natural gas hydrate in the depressurizing production stage, the natural gas hydrate reservoir serves as the resistor, electric energy is converted into heat energy, and accordingly electric heating mining of the natural gas hydrate reservoir is achieved. The method is simple in structure, capable of saving energy, environmentally friendly and easy to control, and provides an effective measure for development of the natural gas hydrate reservoir.

Description

Technical field: [0001] The invention relates to a method in the field of natural gas hydrate development, in particular to a method for exploiting natural gas hydrate reservoirs with the aid of electric heating and decompression of double horizontal wells. Background technique: [0002] Natural gas hydrate is a combustible ice-like crystalline substance that exists in the seabed and onshore permafrost areas. It is formed by small molecular gases such as water and methane under low temperature and high pressure conditions. It has a wide distribution and high energy density. , is a potential high-efficiency clean energy in the future. [0003] At present, depressurization production method, inhibitor injection method and heat injection method are commonly used to exploit natural gas hydrate. Among them, the development speed of decompression method is slow, the development effect is poor, and the scope of application is narrow; the inhibitor injection method mainly injects c...

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Problems solved by technology

Among them, the development speed of decompression method is slow, the development effect is poor, and the scope of application is narrow; the inhibitor injection method mainly injects chemical agents such as methanol and synthetic polyamine into the formation, which is costly and easy to cause damage to the formation and the environment. Relatively limited; the heat injection method needs to use special equipment to inject steam or hot water into the formation, the development cost is high, and it is easy to cause reservoir damage

The exploitation of natural gas hydrate by electric heating of bi-horizontal wells can convert electrical energy into thermal energy for developing gas hydrate reservoirs. Its development speed is fast and its energy utilization rate is high, and it has attracted more and more attention. However, there is no such method as yet. The method of flat well electric heating to assist depressurization to exploit natural gas hydrate reservoirs seriously restricts the research progress of natural gas hydrate reservoir development

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