Impact-rotary-type hole-bottom freezing wire-line coring drilling tool and method for natural gas hydrate

Abstract

The invention relates to an impact-rotary-type hole-bottom freezing wire-line coring drilling tool and method for natural gas hydrate, and belongs to the technical field of geological core drilling. The coring drilling tool is composed of an inner pipe assembly and an outer pipe assembly, the inner pipe assembly comprises a salvage mechanism, an elastic clip positioning mechanism, a suspension mechanism, a single-action mechanism, a buffer mechanism, an impact mechanism and a hole-bottom freezing mechanism. According to the coring method, a natural gas hydrate core is frozen by adopting a refrigerating unit to circle a refrigerant, rapid freezing can be achieved, the freezing effect is good, compared with a traditional refrigeration mechanism, recycling of the refrigerant is uniform in refrigeration, and the cost and auxiliary operation time caused by the supplementary of the refrigerant can be reduced effectively; and the inner pipe assembly does not rotate in the drilling progress, so that damage of the mechanical force caused by the rotation of the drilling tool to the natural gas hydrate core is avoided, moreover, due to the advanced drilling of an inner pipe, the erosion of the natural gas hydrate core by flushing fluid is avoided effectively, and the core recovery rate, integrity and representativeness of the natural gas hydrate core are improved more effectively.

Description

technical field [0001] The invention belongs to the technical field of geological core drilling, and relates to a percussive rotary type natural gas hydrate hole bottom freezing rope core drilling tool and a method, and is especially suitable for freezing sampling of natural gas hydrate drilling in ocean and terrestrial permafrost zones. Background technique [0002] With the rapid development of the economy, the consumption of energy is also increasing day by day. Conventional energy sources such as oil, coal and natural gas are consumed in large quantities. Judging from their remaining reserves, conventional energy sources cannot continue to support modern industry for a long time. The current total amount of methane carbon in the global seafloor gas hydrates is equivalent to twice the total amount of currently known fossil fuel resources such as coal, oil and natural gas. Therefore, natural gas hydrate has become an important backup energy that must be considered in the b...

AI Technical Summary

Problems solved by technology

However, the heat preservation and pressure holding sampler at the bottom of the hole has high requirements on the strength and sealing performance of the ball valve. Once the sealing performance decreases, high-fidelity rock cores cannot be obtained, and the cores may be polluted and eroded by flushing fluid during drilling. The problem

The bottom of the hole freezer needs to consume a large amount of refrigerant, and the process of refrigerant injection will also be accompanied by a large amount of gasification, and the temperature at the upper and lower ends of the freezing chamber is also prone to uneven temperature, resulting in poor freezing effect and low freezing efficiency; It is time-consuming and labor-intensive to inject refrigerant every time, which will not only increase labor costs but also affect the progress of the project

Images