关键词: 采动区, 地面井, 井身结构, 安全防护, 瓦斯抽采

Abstract: In order to solve the problem of gas overrun in coal face of high gas or outburst mine, it is a better way to use surface well to extract gas in coal face of mining area. The principle and technical difficulties of gas surface well extraction under the influence of mining are analyzed. Three kinds of well bore structures of gas surface wells in the mining area are put forward, which are: full well cementing, hanging well completion; partial well cementing, hanging well completion; two-stage well cementing, hanging well completion. The advantages and applicable conditions of three kinds of surface well bore structures are analyzed. Three kinds of protective devices for surface wells in mining areas are developed, including shear protection device, expansion protection device and thick wall rigid comprehensive protection device. It has been applied in Sihe Coal Mine of Jinmei group and achieved good gas drainage effect. Within 200m of the coal face pushing through the surface well, the net gas drainage volume is about 12000m3 / D and the gas concentration is about 85%. After the coal face is pushed 200m over the surface well, the gas drainage volume of the surface well is about 3600 m3 / D, and the gas drainage concentration is about 32.5%. In the working face 60m away from the well position, the average gas concentration of the surface well began to reduce to below 0.41%, to 0.27% on average, and to 26.5% on average, which solved the difficult problem of gas control for the working face, guaranteed the safety of coal mining, achieved good social and economic results, and had good promotion value.