In the light of the shortcomings of the existing whipstock in ultrashort radius radial system, the design idea for a new underreaming whipstock is put forward.

• 针对现有超短半径径向水平钻井技术转向器存在扩孔直径大、成本高的问题,提出新型欠扩孔转向系统的设计方案。