A measuring device and measuring method for the effective impact radius of a gas drainage borehole

Abstract

The invention discloses a measuring device and method for the effective influence radius of a gas extraction drilled hole. The measuring device comprises a coal core gripper, a gas injection part, a gas simulation extraction part and a pressure testing part. According to the measuring device and method, operation that a coring drilled hole is constructed in an original coal seam, then coal core samples are collected and determined in a laboratory is only needed, operation that a series of gas extraction drilled holes and pressure observation drilled holes are constructed in the coal seam is not needed, the engineering quantity is greatly lowered, and the testing success rate is higher than that of a traditional measuring method; the coal quality of the coal core samples, holes and facturesare relatively even, the error brought by gas geological occurrence change to measuring can be avoided, the coal core samples are sealed in the coal core gripper, thus the problem of long exposing time is avoided, and the measuring accuracy rate is high; and tracking and monitoring of the intermediate process that does not reach the extraction time can be achieved, thus the measuring accuracy canbe ensured, and the measuring result can provide theoretical basis and data supporting for reasonable arrangement of the gas extraction drilled hole of the coal seam.

Description

technical field [0001] The invention relates to a measuring device and a measuring method, in particular to a device and a measuring method suitable for measuring the effective influence radius of a gas drainage borehole, and belongs to the technical field of coal mine gas disaster prevention and high-efficiency development. Background technique [0002] Gas drainage by arranging gas drainage boreholes in the coal seam is currently the main means for coal mining enterprises in my country to control gas disasters and gas drainage and utilization. One of the most important tasks in the design of coal seam gas drainage boreholes is to determine the spacing of the drainage boreholes, that is, the distance between two adjacent boreholes. If the distance between the gas drainage boreholes is too small, it will result in a large amount of drilling engineering, high cost, and low economic benefits; Drainage blank zone is left behind, and gas over-limit accidents are prone to occur ...

AI Technical Summary

Problems solved by technology

The disadvantages of the pressure drop method are: ① Since the effective influence radius of coal seam gas drainage boreholes is usually small (within 3m), the distance between the pressure observation boreholes arranged on both sides of the drainage holes and the gas drainage boreholes If the coal seam is relatively close, it is prone to string holes, which will lead to the failure of pressure measurement; ②Because the coal seam is a highly heterogeneous rock material, the pores and fissures in the coal seam are rich and uneven, and there are many small structural fissures in the coal seam, etc. , which will lead to inconsistencies in the pressure measured in each borehole, poor reliability, and inconvenient comparative analysis; ③The success rate of on-site gas pressure testing is not high, and it is actually very difficult to ensure that each borehole has pressure. Disaster

The disadvantages of the residual gas content measurement method are: ①Because the coal seam is heterogeneous and the gas content distribution is very uneven, it is difficult to determine whether the sampling boreholes with low gas content are affected by the extraction or the local gas content is inherently low. ②The exposure time of the coal sample is too long during the sampling process, and the error is relatively large; ③Compared with the pressure drop method, the residual gas content measurement method cannot observe the content change every day, and can only be sampled once after the scheduled extraction time. The intermediate process that has not reached the extraction time cannot be tracked and observed

[0005] In view of the shortcomings of the pressure drop method and the residual gas content measurement method, some researchers have recently proposed a numerical simulation method to eliminate the above-mentioned influencing factors, but it also requires field testing of a large number of parameters as model input, and it is not an economically feasible method. Program

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