Device and method for detecting sealing performance of cross-layer drilling extraction blocking section

Abstract

The embodiment of the invention discloses a device and a method for detecting the sealing performance of a cross-layer drilling extraction blocking section, and relates to the technical field of coal bed gas drilling extraction. The device comprises a three-way pipe fitting, wherein the three-way pipe fitting is provided with a main pipe and a branch pipe connected to one side of the main pipe, an internal channel of the branch pipe communicates with an internal channel of the main pipe, and a pressure monitoring element is arranged on the branch pipe; and an upper opening of the main pipe is connected with a first sealing joint, the first sealing joint is used for being connected with an extraction pipe, a lower opening of the main pipe is connected with a second sealing joint, a liquid return pipe is inserted into the main pipe in a penetrating mode, the lower end of the liquid return pipe penetrates through the second sealing joint to be exposed, the second sealing joint enables the liquid return pipe to be in sealed connection with the lower opening of the main pipe, the upper end of the liquid return pipe penetrates through the first sealing joint to be sleeved with the extraction pipe, and annular spaces with certain gaps are formed between the inner wall of the first sealing joint and the outer wall of the liquid return pipe and between the inner wall of the extraction pipe and the outer wall of the liquid return pipe respectively. According to the device and the method, the sealing performance of the drilling blocking section can be conveniently and rapidly detected, and the position of a leakage point can be accurately detected.

Description

technical field [0001] The invention relates to the technical field of borehole drainage of coalbed methane, in particular to a sealing performance detection device and method for a plugging section of a borehole through a bed. Background technique [0002] Among many gas drilling methods, one is to drill holes from the coal seam floor roadway 2 to the upper coal seam, such as figure 1 As shown, after the construction borehole 8 is completed, a drainage pipe 9 is set in the borehole, and a sealing material is filled around the drainage pipe 9 to form a drainage plugging sealing section 6, so as to extract Gas in Seam 7. [0003] In order to efficiently extract gas, it is necessary to ensure the sealing performance of the drainage borehole. In the process of realizing the invention, the inventor found that in the surrounding rock loosening circle, the rocks are separated from layers, dislocated, squeezed, etc., and due to the impact of the surrounding rock 1 being squeezed,...

AI Technical Summary

Problems solved by technology

In the process of realizing the invention, the inventor found that in the surrounding rock loosening circle, the rocks are separated from layers, dislocated, squeezed, etc., and due to the impact of the surrounding rock 1 being squeezed, the sealing section 6 is easy to drain. Cracks are generated, once the cracks are connected with the surrounding rock cracks (i.e. formed as figure 1 The fracture channel 5) shown in Fig. 2 will affect the plugging and air tightness of the drainage borehole, and then affect the drainage effect

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