复合钻头钻进过程的有限元模拟

Finite Element Simulation of Drilling Processes Using Hybrid Bits

邓嵘 安美 唐东

DENG Rong AN Mei TANG Dong

西南石油大学机电工程学院, 四川 成都 610500

School of Mechatronic Engineering, Southwest Petroleum University, Chengdu, Sichuan 610500, China

设计了一种新型的“2+2”型牙轮PDC复合钻头（包括CL型和BL型两种结构），并采用显式动力学有限元分析方法对两种结构的钻头钻进凝灰岩和花岗岩的物理过程进行了数值模拟。结果表明，CL型钻头适合于钻进较硬的地层，而BL型钻头适合于钻进较软的地层；两种钻头钻进硬岩时的牙轮切削齿轴向力均比钻进软岩时的牙轮切削齿轴向力大，在相同岩石中钻进时，CL型钻头比BL型钻头的牙轮切削齿轴向力大；PDC切削齿轴向载荷沿钻头径向的分布形态与刀翼的冠部形状相似，位于锥顶的切削齿轴向载荷最大；钻压在牙轮和刀翼上的分配与钻头的结构类型相关。

This paper discloses a novel design of a roller cone and a polycrystalline diamond compact (PDC) hybrid drill bit constructed with two roller cones plus two blades. The design includes two types of constructions:cone-leading(CL) and blade-leading(BL) types. The physical processes for drilling tuff and granite using two differently constructed hybrid bits are numerically simulated using an explicit dynamic finite element analysis method. The experimental results demonstrate that the CL-type drill bit proves suitable for drilling hard formations, whereas the BL type can be used for soft earth formations. The axial forces exerted on the roller cone cutting teeth of the two bit types when drilling hard rocks remain larger than those in the case of drilling soft rocks. Furthermore, the CL-type bit exhibits larger imposed axial forces than the BL type when drilling the same rocks. The distribution pattern of the axial loads imposed on the PDC cutters along the radial direction of the bit is very similar to the shape of the blade crown segment, where the maximum axial load occurs at the conic crest. Moreover, the allocation of the weight-on-bit (WOB) on the roller cones and blades is related to the types of bit constructions. The above conclusion deepens the understanding of drilling processes using hybrid bits, which provides useful guidance for the design and on-site selection of drill bits.

10.11885/j.issn.1674-5086.2015.12.19.35