Well wall water leakage control technology of the vertical well drilling method in coal mines based on the grouting of the ground directional drilling
WANG Xuesong;CHENG Hua;RONG Chuanxin;YAO Zhishu;YU Dayou
煤矿钻井井壁为单层结构,在深厚表土层段其渗漏水将严重威胁矿井安全生产,建井阶段井壁接茬部位若存在施工缺陷,则会导致地下水腐蚀锈穿接茬部位金属及焊缝,造成井壁渗漏水,若不及时治理,易引发突水溃砂而酿成淹井事故。为探寻一种行之有效的治理技术,以许疃煤矿副井井筒井壁渗漏水治理为工程背景,开展了煤矿钻井井壁渗漏水治理技术研究。首先,结合矿井水文地质特征等信息分析了钻井法单层井壁渗漏水致因,发现许疃煤矿副井井壁接茬处发生渗漏水的主要原因是地下水中的${text{HCO}}_3^ - $、${text{C}}{{text{l}}^ - }$共同作用腐蚀锈穿井壁接茬部位后,含水层之间越流补给的高压地下水通过孔隙连通性良好的壁后碎石充填层流入井筒内;然后,对比分析了许疃煤矿副井井筒井壁渗漏水治理采用壁后注浆和地面钻孔注浆的可行性与安全性,发现在流砂层中对采用钻井法施工的钢筋混凝土单层井壁进行壁后注浆,安全风险较大,影响井筒正常提升,且存在再次发生渗漏水的风险,而采用地面定向钻孔注浆技术的注浆量大,壁后充填层碎石间孔隙可被水泥浆充分填充,改善井筒防渗和承载能力,且施工人员全程在地面操作,安全性好,不影响井筒正常提升;最后,提出了针对深厚表土层煤矿钻井井壁渗漏水治理的地面定向钻孔注浆技术并进行工程示范,2个钻孔共注入130.9 m3水泥浆,完全充填了94.00~131.40 m层段壁后充填层碎石间孔隙,顺利封堵了井下94 m处出水点,经现场长期观测,该段井壁未再渗漏水。研究结果表明,针对深厚表土层段煤矿钻井井壁渗漏水治理,采用地面定向钻孔注浆技术的治理效果良好,安全性高。研究成果可为深厚表土层煤矿钻井井壁渗漏水治理提供一定的参考。
The coal mine drilling shaft wall is a single-layer structure, and water leakage in the deep alluvium will seriously threaten mine safety. If there are construction defects in the stubble part of the well wall at the construction stage, it will lead to groundwater corrosion and rust through the metal and the weld seam of the stubble part, resulting in water leakage from well wall, which, if not treated promptly, is prone to lead to a sudden water-sand inrush and flooding accidents. In order to explore an effective treatment technology, a research on the control technology of water leakage from the wall of coal mine drilling wells was carried out with the background of water leakage control of wall of sub-well of the Xutong Coal Mine. Firstly, the causes of water leakage from the single-layer well wall of the drilling method were analyzed with the information of hydrogeological characteristics of mine. It was found that the main reason of water leakage at the sub-well wall of Xutong Mine was that the high-pressure groundwater recharged from the aquifers flowed into the well through the gravel packing layer with great pore connectivity, after the corrosive effects of groundwater jointly penetrated the stubs of well walls. Then, the feasibility and safety of using post-wall grouting and ground drilling grouting for water leakage control in the wall of sub-well wall in Xutong Coal Mine were compared and analyzed. Post-wall grouting of reinforced concrete single-layer well walls constructed using the drilling method in fluvial sand layer was found to pose a high safety risk, affecting the normal lifting of wellbore and risking the reoccurrence of water leakage. Ground directional drilling grouting technology had a large grouting volume, and the pores in the gravel filling layer behind the wall can be fully filled by cement slurry, improving the leakage prevention and bearing capacity of the wellbore, and the construction personnel operated on the ground, which was safe and did not affect the normal lifting of the wellbore. Finally, the ground directional drilling grouting technology for water leakage control of coal mine wall in deep alluvium was proposed and demonstrated. A total of 130.9 m3 of cement slurry was injected into the two boreholes, which completely filled the pores space between the gravel of the filling layer behind the wall of the layer from 94.00-131.40 m, and successfully blocked the water outlet point at 94 m downhole. No further water leakage from this section of the well wall had been observed on site over a long period of time. The research results shown that, the ground directional drilling grouting technology had good control effect and high safety for the water leakage of coal mine drilling well wall in deep alluvium. The research results can provide a certain reference for the water leakage control of coal mine drilling well wall in deep alluvium.
drilling wall;well wall stubble;water leakage;ground directional drilling;grouting
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会