【摘要】 针对甘肃平坡煤矿地质钻探中破碎地层的孔壁失稳问题，通过综合分析煤系地层中泥页岩矿物组成、微观结构和孔隙特征，发现该地层以伊利石和蒙脱石为主的黏土矿物含量高，矿物颗粒胶结程度较低，同时大孔和中孔孔隙占总孔隙体积的80%以上，在流体介质侵蚀下易引起孔壁失稳。通过室内试验优选出了性能优良的纳米材料和微泡剂，并结合低固相钻井液研发了适合煤系破碎地层钻探的纳米硅基微泡沫钻井液，该钻井液流动性及滤失性好，能够有效抑制煤系地层变形和孔壁坍塌，具有较强的入渗封堵性能和抑制能力。该新型钻井液在煤系地层钻探的现场应用结果表明，钻探的纯钻率提高了40%,岩芯采取率达到95%,台月效率提升了72%,证明该新型钻井液在煤系破碎地层中具有良好的护壁防塌功能。更多还原

【Abstract】 To address the problem of pore wall instability in the fractured formation during geological drilling at Pingpo Coal Mine in Gansu Province, the mineral compositions, microstructures and pore characteristics of mud shale formation in coal measure strata were comprehensively analyzed. It is found that the clay minerals are mainly composed of illite and montmorillonite with high contents, and the degree of mineral particle cementation is low. At the same time, the large pores and medium pores account for more than 80% of the total pores volume, which is easy to cause pore wall collapse under the erosion of fluid medium. Nano materials and micro-foam agents with excellent performances were selected through laboratory experiments, and a kind of nano silicon-based micro-foam drilling fluid suitable for fractured formation drilling was developed based on the low solid content drilling fluid. The results show that the drilling fluid has a good fluidity and filtration, which can effectively suppress the deformation of coal measure strata and the collapse of pore walls, and has strong infiltration sealing performance and inhibition capabilities. Through the field application of the new drilling fluid in coal measure strata drilling, the pure drilling rate of the drilling hole was increased by 40%, the core recovery rate reached 95% and the monthly efficiency was increased by 72%, which proved that the new drilling fluid has a good wall protection and anti-collapse function in the fractured formation of coal measure strata.更多还原