各向异性岩石破碎过程分析及其钻进用钻头设计研究

Analysis on Anisotropic Rock Fragmentation Process and Research on the Drill Bit Design

钻探工程施工中经常遇到各向异性岩石。钻进各向异性岩石时,不同方向上的岩石强度是不同的。在垂直地层方向上的岩石最容易钻进破碎,其他方向破碎阻力较大,因此岩石压挤核成椭圆形。轴载用于克服岩石的内摩擦阻力和克服来自岩石破碎时产生的反力。在岩石反力垂直分力的作用下,对钻头产生翻转力矩。在此翻转力矩的作用下,钻头偏斜,钻孔弯曲,直接影响钻进效率和钻孔质量。因此,要采取措施解决这个翻转力矩问题。俄罗斯博士СкоромныхВ.В.教授等对此进行多年研究,提出了宜用钻头设计的新思路。

Anisotropic rocks are often encountered in drilling engineering construction; while drilling, the anisotropic rocks strengths in different directions are not the same. The rocks that are vertical to the strata are broken easily, but those drill- ing in other directions have big fragmentation resistance, therefore the core part of rock is deformed into ellipsoidal shape by extrusion. Axial drilling load is mainly used for overcoming internal friction resistance in the rock and the reactions from the rock fragmentation. Under the action of vertical component of rock reaction, overturning moment is produced to the drill bit; under the action of the overturning moment, drill bit is deflected and borehole is deviated, which have direct influence on the penetration rate and hole quality. Doctor CKOpOMm, IX B. B. , who is a Russian professor, and some others have made a lot of studies in resolving the overturning moment, a new idea of drill bit design is proposed for drilling in the aniso- tropic rocks.