The potential of oil and gas resources in southwestern margin of the Sichuan Basin is abundant， however the geological structure is complex and lack of adjacent well data， making difficult drilling construction. Well Chuanmaye 1 is a shale gas geological survey parameter well deployed in the west wing of the Wuzhishan structural belt in southwest Sichuan. The designed depth of the well is 3400m， and the actual completed drilling depth is 3635m. A temporary closure was adopted when drilling to 3437.58m due to the complexity， and side tracking was carried out from 2818m to the completed drilling depth. In response to drilling difficulties， multiple key drilling technologies are summarized， including the handling of small fish accidents in large-diameter boreholes， efficient and rapid drilling with long open holes and large diameters， open hole side tracking in complex formations， and silicon potassium based polymer anti-sloughing drilling fluid systems. These technologies solved the practical problems， ensured the geological objectives， and achieved significant application effects， which can provide reference for similar drilling projects in the same region and support the new round of strategic action for prospecting breakthrough.