不需起拔套管的孔内扩径钻具设计

A borehole reamer without lifting casing

针对下套管护壁后,下部地层出现新的缩颈、垮塌问题,设计了一种不需起拔套管的孔内扩径钻具。描述了该扩径钻具的结构和工作机理,其扩孔尺寸可通过调节滑心滑块的尺寸来改变;导出了冲洗液量与金刚石切削块上的钻压之间的理论公式,为选择合理的扩孔钻进规程提供了一种参考依据。野外应用表明,该扩径钻具能够满足现场扩孔要求,减轻工人劳动强度,提高钻进时效。

Casing drilling technology is essential to borehole which can reduce shrinkage, collapse and save the cost. It is very essential in the soft and heterogeneous layers. A new borehole reamer without lifting casing is introduced in this pa-per. The drilling tool is composed of drilling pipe joint, sliding block, diamond cutting block and guiding rod. The au-thors discuss structure and working mechanism of the new reamer. Diameter of the reamer can be changed by sliding core and sliding block. This characteristic is different from conventional reamer. The matching calculating between drilling fluid volume and the weight of diamond cutting block has been done through hydraulics method. This formula can pro-vide mathematics basis for the reamer design. The results of the field application show that this borehole reamer can meet the reaming requirements, release the labor intensity and improve drilling efficiency.