Deep-water shallow natural gas hydrate solid-state fluidization mining drill bit

Abstract

The invention discloses a deep-water shallow natural gas hydrate solid-state fluidization mining drill bit mainly composed of four parts. The first part comprises a neck hole drill bit for neck hole drilling, and provided with a drilling fluid injection hole and a double spiral guide groove for cleaning a shaft bottom and assisting debris removal. The second part comprises a reaming drill bit forfurther enlarging a wellbore, and having a debris removal passage and a debris removal groove for facilitating debris removal. The third part comprises a refining device for refining a large-diameterhydrate silt cement body and a connecting tool. The fourth part comprises a tapered flow passage arranged inside a drill bit body to increase the jetting speed of the drilling fluid. The deep-water shallow natural gas hydrate solid-state fluidization mining drill bit specifically considers the structure and the physical property of a deep-water shallow gas natural gas hydrate layer, combines the demand of a fluidization mining process for the drill bit, not only realizes the refinement and the fluidization of hydrate silt cement large particle debris, but also solves the problems of debris deposition, poor fluidity and stuck drilling during long-distance horizontal drilling, thereby ensuring the efficient rock breaking and drilling efficiency in the horizontal section of the hydrate layer.

Description

technical field [0001] The invention relates to the technical field of natural gas hydrate exploitation, in particular to a drill bit for solid-state fluidized exploitation of natural gas hydrate in deep water and shallow layers. Background technique [0002] Natural gas hydrate is a kind of "cage compound" synthesized by natural gas and water molecules under high pressure (>10MPa) and low temperature (0-10°C). 80% to 90% of natural gas hydrate is methane, so it is also called methane hydrate. Because most of them are white or light gray crystals, their appearance is similar to ice and snow, and they can be ignited like alcohol blocks, so they are also called " Combustible ice". Gas hydrates exist widely in the world. The discovered gas hydrates mainly exist in the permafrost areas in the Arctic and in the seabed, continental slopes, land bases and trenches worldwide. The storage layer types mainly include sandstone, Sandstone fracture type, fine-grained fracture type a...

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Problems solved by technology

[0005] In view of the above technical problems, the present invention provides a drill bit for solid-state fluidization mining of natural gas hydrate in deep water and shallow layers, so as to realize the refinement and fluidization of large-diameter particles of hydrate sediment, and solve the problem that large cuttings cannot be fluidized and horizontal wells Debris deposition problem, improve the fluidity of hydrate mud slurry, improve rock breaking and drilling efficiency in the horizontal section of shallow gas hydrate layer on deep water seabed

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