Coal rock pressure-maintaining coring inner barrel

Abstract

The invention discloses a coal rock pressure-maintaining coring inner barrel. An inner rubber sleeve is inserted into an outer tube of a rock core holding barrel, a confining pressure cavity is formedbetween the inner rubber sleeve and the inner wall of the outer tube of the holding barrel, sealing plugs and sealing rings are arranged at the two ends of the inner rubber sleeve, the sealing plug and the sealing ring at the upper end are used in cooperation to seal an upper end opening of the confining pressure cavity, the sealing plug and the sealing ring at the lower end are used in cooperation to seal a lower end opening of the confining pressure cavity, one end of an upper end connecting piece is connected with the upper end of the rock core holding barrel in a sealed mode, the other end of the upper end connecting piece is connected with a pressure supply bin, the pressure supply bin is communicated with the confining pressure cavity through a pressure supply pipeline, and a pressure supply valve is arranged on the pressure supply pipeline and used for controlling supply of fluid of reference pressure; and one end of a lower end connecting piece is hermetically connected with the lower end of the hollow rock core holding barrel, the other end of the lower end connecting piece is connected with a ball valve, an outlet pipeline is arranged at the upper end of the rock core holding barrel, and the outlet pipeline at the upper end is provided with an upper end outlet valve. By means of the coal rock pressure-maintaining coring inner barrel, accurate measurement of the gas content can be guaranteed, and the coal rock stratum condition permeability can be tested without taking out a rock core.

Description

technical field [0001] The invention relates to the technical field of coalbed methane exploration and development, in particular to a coal rock pressure-maintaining coring inner cylinder. Background technique [0002] The content and physical properties of coalbed methane under original formation conditions are important parameters for the formulation of coalbed methane exploration and development plans, and coalbed methane workers usually measure them by drilling and coring. At present, the closed coring devices or pressure-holding coring devices used for oil and gas and natural gas hydrates are not suitable for closed coring of coal seams. The wireline coring commonly used in coalbed methane wells is exposed during the core lifting process, and it takes a long time to lift the core, resulting in a large amount of gas in the core escaping, which affects the measurement accuracy of coalbed methane content, especially for crushed coal. [0003] Therefore, it is necessary to...

AI Technical Summary

Problems solved by technology

The wireline coring commonly used in coalbed methane wells is exposed during the core lifting process, and it takes a long time to lift the core, causing a large amount of gas in the core to escape, which affects the measurement accuracy of coalbed methane content, especially for fragmented coal

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