Safe marine drilling rotary pressure-maintaining coring method

Abstract

The invention relates to a safe marine drilling rotary pressure-maintaining coring method, which comprises an outer pipe assembly and an inner pipe assembly mounted in the outer pipe assembly. A drillbit is arranged at the bottom end of the outer pipe assembly, the inner pipe assembly comprises an inner pipe assembly a and an inner pipe assembly b, the inner pipe assembly b is installed in the inner pipe assembly a and can move in the axial direction of the inner pipe assembly a, the inner pipe assembly a comprises a fishing spearhead, an elastic clamping mechanism, a piston pipe, a middle pipe short section, a sealing short section, an energy accumulator connecting pipe, a middle pipe and a pressure-maintaining ball valve turnover sealing mechanism which are sequentially connected from top to bottom, the inner pipe assembly b comprises a lifting device, a connecting mechanism, an elastic clamp hanging mechanism, a single-action mechanism, a conversion connector, an adjusting connector, an energy accumulator connecting pipe, a sealing mechanism, a temperature and pressure instrument connecting pipe, a rock core pipe connecting short section and a rock core pipe which are sequentially connected from top to bottom. The safe rotary pressure-maintaining sampling method can adapt to fourth-system sedimentary stratums and bedrock, and is more reliable in application.

Description

technical field [0001] The invention relates to the technical field of drilling, in particular to a safe marine drilling rotary pressure-maintaining coring method for natural gas hydration. Background technique [0002] Natural gas hydrate is an efficient and clean energy with rich resources, and it is the strategic commanding height of future global energy development. Natural gas hydrate occurs under the seabed of the deep-sea continental slope or buried in sediments in polar regions. Since natural gas hydrate needs to be kept in a stable In order to maintain stability and not decompose under pressure, it is necessary to use a pressure-holding method for collection. The shearing pin is used to trigger the core pipe to be pulled out from the pressure-holding ball valve and then the ball valve is closed. Because the shearing pin works unstable, it is sheared due to bumping and impact during the process of putting in the corer. Once the pin is sheared by the impact, it is ea...

AI Technical Summary

Problems solved by technology

Once the pin is cut off by the impact, it is easy to cause the inner tube assembly of the coring device to be disengaged early, and then the ball valve will be closed in advance, resulting in coring failure. Therefore, the coring device using the shear pin has poor reliability and poor safety.

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