瓦斯抽采钻孔漏气通道快速检测方法

Rapid detection method for air leakage pathways in gas drainage boreholes

  • 摘要: 现有瓦斯抽采钻孔漏气通道检测普遍采用顺序检测法,即依次测量钻孔各测点的瓦斯浓度并通过对比分析判断漏气通道位置,但对于钻孔较长或测点较多的情况,顺序检测法现场检测效率较低。针对上述问题,结合二分法思想,提出了一种瓦斯抽采钻孔漏气通道快速检测方法。在钻孔内沿轴向布置多个测点,利用探杆与瓦斯抽采管实现测点处气体与孔内混合气体的分离;先测定孔底测点瓦斯浓度,若其显著高于孔内平均瓦斯浓度,则判定钻孔存在漏气通道;随后将孔内测点进行二分,检测中间测点瓦斯浓度,若其与孔内平均瓦斯浓度相近,则判定漏气通道位于该测点至孔底区段,若显著高于孔内平均瓦斯浓度,则判定漏气通道位于该测点至孔口区段;进一步对存在漏气通道的区段进行递归二分,通过对比区段内中间测点瓦斯浓度与孔内平均瓦斯浓度,逐步缩小定位范围,最终实现漏气通道的精准、快速定位。现场试验结果表明,所提方法能准确识别漏气通道位置,且与顺序检测法相比检测时间缩短了26.5%,有效提高了检测效率。

     

    Abstract: The sequential detection method is commonly used for detecting air leakage pathways in gas drainage boreholes. This method involves sequentially measuring the gas concentration at various measuring points and identifying the leakage location through comparative analysis. However, for long boreholes or those with numerous measuring points, the on-site detection efficiency of the sequential detection method is low. To address this issue, this paper proposed a rapid detection method for air leakage pathways in gas drainage boreholes based on the bisection method. Multiple measuring points were arranged axially within the borehole. A probe rod and a gas drainage pipe were used to separate the gas at a specific measuring point from the mixed gas inside the borehole. First, the gas concentration at the borehole bottom measuring point was measured. If it was significantly higher than the average in-hole gas concentration, the presence of an air leakage pathway in the borehole was confirmed. Subsequently, the in-hole measuring points were bisected, and the gas concentration at the intermediate measuring point was measured. If this concentration was close to the average in-hole gas concentration, the air leakage pathway was determined to be located in the section from that point to the borehole bottom; if it was significantly higher, the pathway was determined to be in the section from that point to the borehole collar. The section identified as containing the air leakage pathway underwent further recursive bisection. By comparing the gas concentration at the intermediate measuring point within a section with the average in-hole gas concentration, the localization range was progressively narrowed, which ultimately achieved the precise and rapid localization of the air leakage pathway. The field experiment results showed that the proposed method accurately identified the location of the air leakage pathway. Compared with the sequential detection method, the detection time was shortened by 26.5%. This improvement demonstrates that the proposed method effectively improves detection efficiency.

     

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