Icebound type pressure-maintaining and temperature-preserving sampler

Abstract

The invention relates to an icebound type pressure-maintaining and temperature-preserving sampler. The icebound type pressure-maintaining and temperature-preserving sampler comprises a drilling in / sampling switching mechanism, a refrigerating fluid circulating system, a slurry ice valve and core valve in-situ generation mechanism, a core accommodating pipe single acting mechanism and channels I, II, III, IV, V and VI; the slurry ice valve and the core valve which are generated by freezing are used to replace mechanical valves of a ball valve or a plate valve and the like to close an upper port and an lower port of a sampling drilling tool, solid impurities in a hole have no influence on the closing process, thereby the sampler has high reliability and solves the problems of difficult starting, difficult closing caused by easy blockage of sundries in the hole and the like of the tradition mechanical valves and improves pressure-maintaining reliability and success ratio; and moreover, radial dimension can be smaller so as to be beneficial to acquiring cores with larger diameters and improving hydrate coring recovery factor. Tests prove that the ice valve can realize the sealing of 25MPa, which is suitable for drilling on hydrate with an inner hole liquid column reaching 2500m; and a hydro hammer drives a reciprocating pump, which utilizes the slurry as dynamic medium, thereby avoiding the complexity brought by an electric structure and having simplicity and reliability.

Description

Technical field: [0001] The invention relates to a drilling and sampling tool, in particular to a pressure-preserving and heat-retaining sampling drilling tool for natural gas hydrate drilling and sampling. Background technique [0002] Natural gas hydrate has the characteristics of wide distribution, huge reserves, and high energy density. It is a potential clean new energy for human beings in the future, and has an important impact on the global environment and the safety of marine drilling production. Experts preliminarily estimate that the total energy contained in natural gas hydrates in my country is more than twice the sum of the energy of known oil, natural gas and coal in the country. The exploration and development of natural gas hydrates is of great significance. [0003] The special form of natural gas hydrate determines that its stable existence requires high-pressure and low-temperature conditions, and the drilling tools for drilling and sampling are required t...

AI Technical Summary

Problems solved by technology

The existing pressure-holding drilling tools at home and abroad use mechanical structures such as ball valves or plate valves to close the lower port of the sampling drilling tool, so as to realize the pressure-holding function. The outstanding problem is that the ball valve or plate valve is often difficult to close normally, so that the pressure-holding cannot be performed normally. function, the number of times the function of maintaining pressure accounts for less than 60% of the total sampling times, and the reliability is poor; moreover, the ball valve or plate valve occupies a large radial dimension in design, so the diameter of the gas hydrate core is small and it is easy to be The core recovery rate is low, often less than 50%, which cannot meet the requirements of gas hydrate exploration and scientific research.

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