Method for exploiting natural gas hydrates by using high-pressure thermal jetting

Abstract

The invention relates to a method for exploiting natural gas hydrates by using high-pressure thermal jetting, comprising the following steps of: placing a high-pressure jetting device in an exploiting well; sending thermal fluids into a water injection pipe and a telescopic water gun through a high-pressure pump for spraying; causing high-speed jetting flows to directly act on the natural gas hydrates in the working radii of the high-speed jetting flows to cut and decompose the natural gas hydrates, changing non-decomposed natural gas hydrates into small blocks, bringing the small blocks into an exploiting pipe along with return flows, and then causing the small blocks together with the gas hydrates to rise to a gas-liquid separation device; separating gas and liquid through the gas-liquid separation device, and sending the gas into a gas recovering device. The invention solves the problem of small exploitation range in the exploitation process of the natural gas hydrates, ensures the thermal fluids to act on the surfaces of the non-cracked natural gas hydrates all the time, has a good thermal conduction effect and overcomes or reduces the self protection of the natural gas hydrates; and the telescopic water gun on a nozzle can not only be horizontally rotated, but also can be moved up and down along a vertical shaft by utilizing the power of a drilling machine, thereby ensuring the cutting of large-scale natural gas hydrate ledges.

Description

Technical field: [0001] The invention relates to a method for exploiting natural gas hydrate, in particular to a method for exploiting natural gas hydrate by using high-pressure hot jet flow. Background technique: [0002] Existing natural gas hydrate mining methods include thermal excitation method, depressurization method, and chemical reagent injection method. The mining mechanism of the above methods is to break the conditions for the stable existence of hydrates, promote their decomposition, and achieve the purpose of mining. According to the article "Natural Gas Hydrate Exploitation - Taking Malik Drilling as an Example" written by Luan Xiwu and others, the thermal stimulation method was successfully used in the Malik gas field in Canada, but the thermal stimulation method mainly uses heat conduction to decompose gas hydrate The mining area is small, and thermal convection does not contribute much to the decomposition of natural gas hydrate due to the limitation of the...

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Problems solved by technology

According to the article "Natural Gas Hydrate Exploitation-Taking Malik Drilling as an Example" written by Luan Xiwu and others, the Malik gas field in Canada has been successfully exploited by the thermal stimulation method, but the thermal stimulation method mainly uses heat conduction to decompose natural gas hydrate. The mining area is small, and thermal convection does not make much contribution to the decomposition of natural gas hydrate due to the limitation of contact area, and its heat loss is too large; This paper introduces the situation of mining hydrates by depressurization method in Russia. This method has achieved good mining results, but the depressurization method can only be used effectively when there are natural gas fields in the lower part of the gas hydrate deposit. The application of the method is limited by the occurrence conditions of natural gas hydrate

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