Hydrate solid-state fluidized mining variable-diameter double-layer pipe connecting device

Abstract

The invention discloses a hydrate solid-state fluidized mining variable-diameter double-layer pipe connecting device, which is used for connection and flow channel conversion of a small-diameter double-layer continuous pipe and a large-diameter double-layer structure tool pipe string in a hydrate fluidized mining in the pit. The small-diameter double-layer continuous pipe outer tube is a light tube, and a six-valve type slip is extruded by a pressing sleeve to engage the outer tube; the pressing sleeve is screwed to a variable-diameter joint body; a large-diameter double-layer structure pipe string outer tube is threadingly connected to the variable-diameter joint body; the variable-diameter joint body has two flow channels inside; the outer flow channel communicates with outer chambers ofthe small-diameter double-layer continuous pipe and the large-diameter double-layer structure pipe string, and the inner flow channel communicates with inner chambers of the small-diameter double-layer continuous pipe and the large-diameter double-layer structure pipe string; and the variable-diameter outer flow channel is evenly divided into four annular flow channels, and the cross section thereof is a convex curved surface. The device realizes connection of the double-layer structure pipe strings of different diameters, increases the flow area at a diameter-variable part, reduces the pressure drop and vibration at the joint, and improves the tensile resistance of the light pipe connection.

Description

technical field [0001] The invention relates to the technical field of natural gas hydrate exploitation, in particular to a variable-diameter double-layer pipe connection device for hydrate solid-state fluidization exploitation. technical background [0002] Natural gas hydrate is a clean, high-quality, and efficient new energy source discovered in the world. It is a research hotspot in the oil and gas industry and an indispensable material in future energy strategies. The global reserves of natural gas hydrate are huge, but the current development is not yet mature, especially in the ocean, the traditional mining methods include depressurization method, heat injection method, chemical inhibitor method and CO 2 Displacement mining methods, etc. These methods have only carried out short-term trial production technology demonstration verifications for gas hydrates in polar sandstone and sea sandstone reservoirs, and their safety cannot be fully guaranteed. Therefore, for the ...

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Problems solved by technology

[0004] Aiming at the problems existing in the prior art, the object of the present invention is to provide a connecting device for variable-diameter double-layer continuous pipes in the solid fluidized exploitation of natural gas hydrate, which solves the problem of large-diameter double-layer structure pipe strings and small-diameter double-layer continuous pipes. The variable-diameter connection problem between the coiled tubes solves the connection problem between the connecting device and the small-diameter double-layer coiled tubes, and reduces the pressure drop and vibration caused by the high-pressure liquid flowing in different directions

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