基于时间分源法的CO2相变致裂抽采有效半径测定

Determination of Drainage Effective Radius of CO2 Phase Transition Fracturing Based on Time-source Method

针对CO2相变致裂抽采有效半径测定尚无统一标准的现状,对相对瓦斯压力法局限性进行归纳,进一步明确抽采半径的概念。基于SF6示踪法,采用抽采数据处理与分析方式,建立时间分源法,并进行现场试验。研究表明:抽采影响半径和抽采有效半径之间存在时间效应,抽采时间是区分二者的关键因素;时间分源法将抽采时间分为影响时间和承接时间2部分,通过SF6示踪法及现场抽采数据分析得到一定抽采时间下抽采有效半径,更能够真实反映钻孔抽采情况;在大平煤矿3号煤层运输大巷实测得到,抽采时间为120 d时,CO2相变致裂抽采有效半径为12 m;抽采时间为148 d时,抽采有效半径达到16 m。

There is no uniform standard for determining the drainage effective radius of CO2 phase transition fracturing in view of the fact,we analyze the traditional measurement for drainage effective radius,clarify definition of drainage radius.The time-source method is established based on SF6 tracer method and test data,and it was tested in coal mine.The research shows there is time effect between drainage influence radius and drainage effective radius,and the drainage time is the key factor to distinguish them;the time-source method divides the drainage time into drainage effective time and drainage compensation time.The drainage effective radius under a certain time is obtained through SF6 tracer method and analysis of the field data.It can reflect the drainage situation of boreholes more accurately;the test-in-place experimented at main haulage roadway in No.3 coal seam of Daping Coal Mine.The result shows that the drainage effective radius after CO2 phase transition fracturing is 12 m when the drainage time is 120 d and drainage effective radius is 16 m when the drainage time is 148 d.