Frozen soil layer parasitic pipe-provided vacuum sleeve cementation heat insulation cooling system and cooling method

Abstract

The invention provides a frozen soil layer parasitic pipe-provided vacuum sleeve cementation heat insulation cooling system and a cooling method. The heat insulation cooling system involves a centralpipe, a vacuum heat insulation sleeve, a low-temperature fluid injection pipe, a low-temperature fluid return pipe, a refrigeration system, a low-temperature fluid pool, a valve flowmeter and a vacuumpump; and the cooling method comprises the following steps of carrying out geological investigation to determine the position and thickness of a frozen soil layer of a stratum, and after the frozen soil stratum is drilled, cementing the frozen soil stratum by using the sleeve, and arranging the central pipe. The annular space between the central pipe and the vacuum heat insulation sleeve circulates low-temperature fluid and absorbs the high-temperature drilling fluid heat in the central pipe; and refrigeration equipment is arranged on the ground, the low-temperature fluid circulated back to the ground is subjected to cooling treatment, the cooled fluid enters the annular space again, and the steps are repeated until the whole drilling operation is finished. The system and the method effectively solve the technical problem that in the drilling construction process of the frozen soil stratum, the high temperature drilling fluid upwards returned from the deep stratum exchanges heat withthe shallow frozen soil so as to cause collapse, caused by melting of the frozen soil, of the well wall at the frozen soil layer.

Description

technical field [0001] The invention belongs to the field of borehole wall stabilization in frozen soil drilling, and in particular relates to a thermal insulation cooling system and cooling method for vacuum casing cementing with parasitic tubes in frozen soil layer. Background technique [0002] Permafrost refers to various rocks and soils with a temperature below 0°C and ice. It is a key problem in drilling operations in polar permafrost. During deep drilling, due to the high temperature at the bottom of the well, the high-temperature drilling fluid returned The temperature can even reach above 200°C. On the one hand, the temperature of the permafrost layer containing natural gas hydrates rises due to the excessively high temperature of the circulating drilling fluid, which decomposes a large amount of methane gas. If the decomposition process is out of control, a large amount of methane gas leaks may lead to blowout accidents and will enter the atmosphere. Seriously dam...

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Problems solved by technology

[0003] In order to solve the technical problem that the high-temperature drilling fluid returned from the deep strata and the shallow permafrost undergo heat exchange in the current drilling construction process of the permafrost strata, which will lead to the collapse of the permafrost well wall caused by the thawing of the permafrost, the invention aims at the permafrost stratum Provide a vacuum casing cementing heat insulation and cooling system and cooling method with parasitic tubes in permafrost during deep drilling to protect the borehole wall in shallow permafrost

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