A kind of preparation method of hydrate core in permafrost zone

Abstract

The invention relates to a frozen earth zone hydrate core preparation method. Firstly, proper raw materials are selected according to mineral components and contents of actual frozen earth zone hydrate formation core samples, the particle size and the ratio of base sand are determined, and core particles are cemented by oil well cement to prepare a framework core. An appropriate quantity of hydrate generation accelerators are selected and added into pure water to prepare solution, and the cores are saturated in a vacuum pumping mode by the aid of the prepared solution. The mass of the solution needed by the cores is calculated according to saturation of hydrate in the cores to be prepared, and the mass of the solution in the cores is controlled by controlling the temperature and drying time of the cores in a vacuum drying oven. The cores with different liquid contents are placed into a high-pressure autoclave, the pressure of methane gas led into the high-pressure autoclave is increased by reducing the internal temperature of the high-pressure autoclave, and a frozen earth zone hydrate generation environment is simulated to prepare the hydrate cores. By the preparation method, saturation of the hydrate in the cores can be effectively controlled, various hydrate cores with different saturation can be generated by one experiment, and experimental period is greatly shortened.

Description

technical field [0001] The invention relates to a natural gas hydrate reservoir simulation experiment technology in the field of unconventional energy, in particular to a method for preparing a simulated permafrost zone hydrate formation core. Background technique [0002] Natural gas hydrate is a crystalline solid substance similar to ice formed by water and natural gas (mainly methane) under high pressure and low temperature conditions, also known as "combustible ice". Natural gas hydrate has extremely high energy density, and has been regarded by various countries as an effective substitute for conventional energy such as oil and natural gas in the future, and has great commercial exploitation value. At present, China has announced the success of the first trial production of natural gas hydrate in the Shenhu area of ​​the South China Sea. Compared with hydrates in deep sea areas, although the reserves of hydrates in the tundra are relatively small, their relative mining ...

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Problems solved by technology

[0004] In view of the deficiencies of the prior art, this application proposes a method for the preparation of hydrate cores in permafrost and the control of hydrate saturation, which overcomes the complexity of the operating steps in the prior art, and the long experimental period in the process of hydrate formation. To solve the problem, a method that can accelerate the formation of hydrates is proposed, and in one experiment, multiple cores with different hydrate saturations can be generated, which greatly shortens the experimental preparation cycle

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