To study the behavior of gas extraction from the protected layer by surface drilling, the common characteristics of gas extraction concentration and gas extraction quantity are summarized through the collection of key parameters of surface drilling and a combination of data and figures, with the background of 11⁻² coal protection 13⁻¹ coal in the Huainan mining area. The research results show that the flow of pressure relief gas extraction of the protected layer by surface drilling has three stages: a rising period, stable period, and decay period. When the extraction processes of multiple surface wells on the same working face are coordinated, the extraction flow is superimposed, and the extraction volume of surface drilling shows an increasing trend and fluctuates with the location of the drilling. The extraction flow rate before ground drilling is relatively small, and the extraction flow rate increases after ground drilling. This behavior is further confirmed by field observation of mining changes in the protective layer and the expansion and deformation of the protected layer. The periodic variation in the surface drilling and extraction quantity is affected primarily by the mining movement of the working face of the protective layer. Specifically, it is affected by factors such as the mining progress of the working face of the protective layer, mining height, degree of compacted goaf, degree of pressure relief of the protected layer, original gas content, and other measures taken to extract the protected layer.

中文翻译：

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淮南露天钻井保护层减压采气特点

为研究地表钻探保护层采气行为，通过采集地面钻探关键参数，结合数据和数字，总结出采气浓度和采气量的共同特征，背景为11 ⁻²煤炭保护 13 ⁻¹淮南矿区的煤炭。研究结果表明，地表钻井对保护层卸压气抽采的流动具有上升期、稳定期和衰减期三个阶段。当同一工作面多口井的采油过程协调时，采油流叠加，地面钻井采油量呈增加趋势，并随着钻井位置的变化而波动。地面钻孔前抽气流量较小，地面钻孔后抽气流量增加。通过现场观察保护层的开采变化和保护层的膨胀变形，进一步证实了这种行为。地表钻采量的周期性变化主要受保护层工作面开采运动的影响。具体而言，受保护层工作面开采进度、开采高度、采空区压实程度、保护层卸压程度、原始含气量等因素的影响，以及采取的其他开采保护措施。层。