软硬互层煤岩体传统钻进工艺钻孔偏斜规律研究

Research on the deviation law of drilling hole in traditional drilling technology of soft and hard interbedded coal and rock mass

为获得软硬互层条件下瓦斯抽采钻孔轨迹的偏斜规律,本文采用相似模拟的方法从实验室尺度上对钻孔的偏斜规律进行研究。根据具体的钻孔施工地质条件,在实验室搭建三维相似地质模型,为了研究软硬互层条件下的钻孔偏斜律,采用相似模拟实验的方法,在实验室搭建三维相似地质模型,分析了钻孔在不同岩性岩层、不同倾角岩层中的偏斜特征和钻孔轨迹,不同钻进速度、不同应力等条件下的钻孔偏斜规律。结果表明:①钻孔的偏斜与岩性密切相关,当岩性较软时,发生偏斜程度不大,当岩性较硬时,发生偏斜的程度就会相对较大。②钻孔的偏斜与钻速密切相关,当钻速较小时,此时钻进过程中,容易发生偏斜,发生偏斜程度相对较大,当钻速逐渐变大时,发生偏斜的程度就会相对较小。③钻孔的偏斜与钻进角度密切相关,当钻进角度较小时,此时钻进过程中,容易发生偏斜,发生偏斜程度相对较大,当钻进角度逐渐变大时,发生偏斜的程度就会相对较小。

In order to obtain the deviation law of gas extraction borehole track under the condition of interbedded soft and hard layers,the similarity simulation method is used to study the deviation law of borehole from the laboratory scale.According to specific drilling construction of geological conditions,similar in laboratory set up 3D geological model,in order to study hard and soft layer under the condition of each borehole deflection law,adopt the method of analog simulation experiment,similar in laboratory set up 3D geological model,analyzed the borehole in different lithology strata and deflection angle strata characteristics and borehole trajectory,the deviation law of drilling hole under different drilling speed and stress.The results show that:①The deviation of borehole is closely related to lithology.When the lithology is soft,the deviation degree will be small,and when the lithology is hard,the deviation degree will be relatively large.②The deviation of the drilling hole is closely related to the drilling rate.When the drilling rate is small,the deviation degree is relatively large in the process of drilling.When the drilling rate gradually increases,the deviation degree will be relatively small.③The deviation of the drilling hole is closely related to the drilling angle.When the drilling angle is small,the deviation is easy to occur during the drilling process.The deviation degree is relatively large.