Process for exploiting ocean gas hydrate by utilizing terrestrial heat

Abstract

The invention relates to a process for exploiting ocean gas hydrate by utilizing terrestrial heat, comprising the following steps: 1) digging a branch well on a target hot rock stratum; 2) utilizing a casing to penetrate through gas hydrate treasure, digging a directional well on the target hot rock stratum, perforating the casing penetrating through the gas hydrate treasure, and sealing the mouth of the well; 3) pressing seawater into the target hot rock stratum by utilizing a pump, pressing the seawater into the directional well after heat exchange heating, leading the seawater into the area of the gas hydrate treasure from the perforation of the casing, and obtaining decomposed gas hydrate and cooled seawater; and 4) transporting the gas hydrate and the cooled seawater to a sea surface by utilizing a gas-liquid recycling tube, separating the gas hydrate from the cooled seawater at an outlet, and collecting natural gas. The invention has the beneficial effect that the invention greatly reduces the heat injection cost in the exploration process, causes the exploration process to continuously develop and has less pollution and damage on environment, and each technical index in the exploration process can refer to the existing petroleum exploration process so as to lower difficulty for realizing the exploration process.

Description

technical field [0001] The invention relates to a technique for exploiting marine natural gas hydrate by utilizing geothermal energy. Background technique [0002] For nearly a century, traditional energy sources such as oil and coal have been exhausted, but people's demand for energy has continued unabated. Due to its huge reserves, high energy density, wide distribution, and large scale, natural gas hydrate is considered to be the most ideal alternative energy source in the 21st century. But gas hydrate can only become a real energy source if the problem of its exploitation is solved. After long-term research, the industry has proposed three typical traditional mining methods: thermal activation method, decompression method and chemical inhibitor injection method. However, these mining methods have some defects that cannot meet commercial mining. The thermal excitation method has low efficiency, and the heating area is small, and the energy consumption is large; for the ...

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Problems solved by technology

After long-term research, the industry has proposed three typical traditional mining methods: thermal activation method, decompression method and chemical inhibitor injection method. However, these mining methods have some defects that cannot meet commercial mining.

The thermal excitation method has low efficiency, and the heating area is small, and the energy consumption is large; for the decompression method, it is economically feasible only when the gas hydrate reservoir is located near the temperature-pressure equilibrium boundary. After a period of time, the decomposing method slows down or even stops decomposing; the chemical inhibitor injection method has a slow effect on the natural gas hydrate layer, and the cost of chemical reagents required is very high, and it will also bring some adverse environmental problems. Studies have shown that my country's South China Sea seabed Natural gas hydrate and geothermal resources are very rich, how to develop such resources reasonably and effectively has become the focus of researchers

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