钻孔液浸泡下煤矿膨胀性泥岩钻孔缩径实验研究

Experimental Study on Coalmine Boreholes Shrinkage Crossing Expansive Mudstone Under Drilling Fluid Soaking

针对煤矿井下膨胀性泥岩钻孔遇水缩径问题,探讨了聚胺钻孔液在煤矿膨胀性泥岩钻孔水力排渣系统中的应用。在线膨胀实验和单轴压缩实验的基础上,研究了不同钻孔液浸泡对泥岩膨胀和强度特性的影响;通过理论计算并结合相似模拟实验,分析研究了不同钻孔液对煤矿膨胀性泥岩钻孔缩径变形的影响。研究表明:聚胺钻孔液能较好地降低泥岩含水率,减小水化膨胀,抑制泥岩膨胀变形;在钻孔液中添加铝盐络合物等封堵剂可以大幅度改善泥岩力学性质,降低水力排渣过程对泥岩强度的弱化作用;聚胺钻孔液体系能够有效地抑制泥岩钻孔缩径,缩径率降低21%。

In response to the issues of boreholes shrinkage crossing expansive mudstone in coalmine,we discusse the application of polyamines drilling fluid in drilling hydraulic discharge system. Based on linear expansion experiment and uniaxial compression experiments,mudstone expansion and strength characteristics were studied in different drilling fluid. The deformation of expansive mudstone boreholes in different drilling fluid is also analyzed and studied by theoretical calculation and similarity simulation experiment. Results show that polyamine drilling fluid can reduce the moisture content of mudstone,reduce the hydration expansion,and inhibit mudstone expansive deformation. Aluminum salt complex is added in the drilling fluid,which can significantly improve mudstone mechanical properties and reduce the weakening effect of mudstone strength in the hydraulic discharge process. Polyamine drilling fluid system can effectively inhibit mudstone boreholes shrinkage,and shrinkage rate is reduced by 21%.