煤矿深部膨胀性泥岩钻孔变形机理及控制技术数值研究∗

摘要

In the process of hydraulic slagging in expansive mudstone borehole in deep coal mine,surrounding rock deformation and softening and borehole shrinkage were obvious and seri-ous. A new drilling technique using polyamine drilling fluid was proposed,and the stress field and displacement changes around the borehole in the expansive mudstone before and after drilling fluid soaking were analyzed by numerical simulation software ANSYS. The results were applied to gas drainage and drilling,and the stabilizing effect was great. The test results showed that when the surrounding rocks were soaked by the polyamine drilling fluid,the equivalent stress of borehole surrounding rock was increased,while the stability of surrounding rock was improved and the borehole shrinkage was decreased,which effectively prevented the j amming and sticking of drilling tool in expansive mudstone and increased the borehole gas drainage time.%煤矿深部膨胀性泥岩钻孔水力排渣过程中，围岩膨胀变形和岩性软化，使钻孔缩径严重。提出一种聚胺钻孔液成孔新技术，利用数值模拟软件ANSYS模拟分析了钻孔液浸泡前后煤矿膨胀性泥岩钻孔周围应力场和位移变化，在现场抽放钻孔进行了应用，稳定孔壁效果显著。试验结果表明聚胺钻孔液浸泡后，钻孔围岩等效应力增加，围岩稳定性增强，钻孔缩径量明显降低，有效防止了膨胀性泥岩钻孔缩径卡钻、夹钻，增加了钻孔抽放时间。