Hole bottom freezing cord coring drill and coring method thereof

Abstract

The invention relates to a hole bottom freezing cord coring drill and a coring method thereof. In the invention, liquid nitrogen is taken as a refrigerant; the liquid nitrogen absorbs heat in the gasification process so as to freeze a core at a hole bottom and inhibit a natural gas hydrate from being decomposed. The drill comprises an outer tube assembly and an inner tube assembly; and in the process of acquiring the core, a sand hitch is utilized to drag the inner tube assembly out from the outer tube assembly, an end cover and a clamp spring are dismounted, a semi-closed tube and a core sample are pumped out together from a core tube, the two ends of the semi-closed tube are sealed by rubber plugs, and the core sample and the semi-closed tube are stored in a liquid nitrogen hold-up vessel or a high-pressure container together. The invention has the advantages that rapid freezing can be realized, and the freezing effect is good; since cord coring and hole bottom freezing are combined, rapid coring without lifting the drill is achieved; in the drilling process, the inner tube assembly does not rotate, thus damages on a hydras core caused by mechanical force generated by rotation of the drill is avoided to a greater degree, the percentage of coring, the core integrity degree and the representativeness are more effectively improved; and semi-closed tube type rapid ground surfacesampling is adopted, thus the core can be rapidly obtained from the ground surface.

Description

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AI Technical Summary

Benefits of technology

This technology allows for quicker cooling without damaging or affecting the structure inside hydrocarbon reserves (HCO). By combining ice crystals from liquids into solid particles instead of gas) it provides better results compared to traditional methods like vacuum extraction. Additionally, this method avoides rotating parts that could cause harm if used frequently while drillings through sedimentary rocks filled holes.

Problems solved by technology

Technological Problems In this patented technical problem addressed in the patents are how to efficiently create stable gamma ray hydrocarbon (NGH) sample from naturally occurring sources like shale deposits without decompositing them overtime due to factors including environmental conditions. Current methods involve either wet sand blasting or rotating cutting tools, but each suffers certain drawbacks.

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