Device and method for in-situ rapid testing of coal seam permeability by portable through-bed drilling

Abstract

The invention discloses a portable device for quickly testing the permeability of coal seams in situ by drilling through layers. The gas outlet of the mobile strap-type gas cylinder is connected with a high-pressure hose, and the other end of the high-pressure hose is connected with the gas injection pipe from the push block. The gas injection pipe passes through the upper and middle packers in turn and is inserted into the lower packer, and the three packers are arranged at intervals, and a gas injection pipe is opened on the pipe wall between the middle and lower packers. The sieve hole, the measuring tube is divided into the outer section of the hole and the inner section of the hole. The inner section of the hole passes through the upper packer and extends between the upper packer and the middle packer. The outer section of the hole is equipped with a second stop valve, a second Two gas pressure gauges and a second gas flow meter, the lower end of the push rod is connected to the upper end of the push block. At the same time, the invention also provides a method for quickly testing the permeability of the coal seam in situ through a portable through-bed drilling hole. It can realize the convenience and speed from the testing stage to the data processing, and the process is simple, cost saving and high in efficiency.

Description

technical field [0001] The invention relates to the test of coal seam permeability in coal mining, in particular to a device for quickly testing coal seam permeability in situ through a portable through-bed drilling hole, and at the same time provides a mathematical model that facilitates the establishment of the data measured by the device to measure the permeability method of calculation. Background technique [0002] As a porous medium, coal body has certain permeability, that is, fluid with certain particles can permeate into coal body, and even flow through coal body and transfer to the next medium. The determination of coal seam permeability has extremely important practical significance for the evaluation of coal seam pumpability, the reasonable spatial arrangement of gas drainage boreholes, the determination of reasonable sealing positions of boreholes, and the evolution of coal seam permeability during gas drainage. Engineering value; at the same time, the redistri...

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Problems solved by technology

Due to the large variation of coal seam occurrence conditions, even in the same coal seam, the permeability of coal at different locations and depths may have a large degree of difference, which greatly affects the evaluation of coal seam gas drainage effect

[0003] In the field of coal permeability research, many experts have proposed laboratory seepage experiment methods, but this method has certain defects: the extraction of coal samples destroys the objective environment in which the coal is located, and laboratory seepage experiments Ignoring the dynamic evolution process of coal fractures under the influence of mining

Since multiple sets of flow velocity data obtained under different pressure conditions are required to obtain accurate permeability, the calculation time is too long, and the accurate value of permeability cannot be obtained in a short time

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