Seabed natural gas hydrate pressure maintaining and temperature preserving rope core bit and operation method thereof

Abstract

The invention discloses a seabed natural gas hydrate pressure maintaining and temperature preserving rope core bit. An outer pipe assembly, an inner pipe assembly, a pressure maintaining assembly, a heat preservation assembly, a drill running monitoring assembly, a temperature sensor and a pressure sensor are included. The outer pipe assembly comprises an outer pipe, a reamer and a drill bit, theouter pipe is connected with the reamer, and the reamer is connected with the annular drill bit. The inner pipe assembly is arranged in the outer pipe assembly and comprises an elastic clamp mechanism, an inner pipe, a rock core pipe, a snap spring and a snap spring base, the elastic clamp mechanism is arranged in the outer pipe and fixedly connected with the drill running monitoring assembly, thedrill running monitoring assembly is connected with the upper end of an inner pipe connector, the lower end of the inner pipe connector is connected with the upper end of the inner pipe, the rock core pipe is sleeved with the inner pipe, the lower end of the inner pipe is connected with the snap spring base, and the snap spring base is provided with the snap spring and connected with the pressuremaintaining assembly. The heat preservation assembly is arranged on the outer wall of the inner pipe assembly. The temperature sensor and the pressure sensor are arranged at the bottom of the inner pipe connector. By means of the seabed natural gas hydrate pressure maintaining and temperature preserving rope core bit, pressure maintaining and temperature preserving rope coring can be implementedto the seabed natural gas hydrate.

Description

technical field [0001] The invention relates to a submarine natural gas hydrate fidelity wireline coring drilling tool and an operating method thereof. Background technique [0002] The subsea drilling rig is the key technical equipment for the exploration of seabed mineral resources. The subsea drilling rig is used to drill and core the subsea natural gas hydrate mining area, and accurately obtain information such as the distribution, burial depth, grade, and reserves of the subsea natural gas hydrate in the mining area, so as to provide Provide technical support for mining area design, mining method selection, mining geological environment monitoring, etc. [0003] From the temperature-pressure characteristic curve of seabed natural gas hydrate, it can be seen that only under certain temperature and pressure conditions, seabed natural gas hydrate can exist stably. When the temperature and pressure conditions for the stable existence of seabed gas hydrates are broken, seab...

AI Technical Summary

Problems solved by technology

This makes it possible to use the existing subsea gas hydrate pressure-holding wireline core drilling tool to drill and core the subsea gas hydrate, and the subsea gas hydrate pressure-holding wireline The rise of seawater temperature will inevitably lead to some subsea gas hydrate core samples drilled in the subsea gas hydrate pressure-holding rope core drilling tool to absorb heat and decompose and gasify, thus affecting the distribution of subsea gas hydrate in the mining area Accurate analysis of , grade and reserves

[0004] At the same time, during the drilling and coring process of subsea natural gas hydrate, when the core enters the inner tube assembly, it will rub against the inner tube assembly, and the core will exert an upward force on the inner tube assembly. When its force is greater than the support force of the ejection chamber to the ejection assembly, the ejection assembly will retract, resulting in failure of the ejection chamber’s limit to the inner tube assembly, and the inner pipe assembly will move upward along the outer pipe assembly causing drilling accident

If the drilling accident is not dealt with in time, the drilled core will enter the outer tube assembly during subsequent drilling, causing blockage of the outer tube assembly, which will not only cause the drill bit to burn out due to lack of cooling fluid, but also Since the outer pipe assembly is equipped with a rock core, the new inner pipe assembly cannot be put in place when it is lowered next time, resulting in a series of drilling accidents of multiple inner pipe assemblies, which in turn leads to the scrapping of the drill hole

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