一种同轴双向回转模式的钻具结构设计及振动模拟

Structural design and vibration simulation of a coaxial contra-rotary drilling tool

摘要:

钻进时的振动会引起钻具疲劳失效和损坏，为提高井下钻具的稳定性，本文设计了依靠行星齿轮系驱动内外钻头同轴双向回转的钻具结构。通过对其核心的齿轮、密封、轴承等部件进行的强度校核，证明该结构的设计强度能够满足正常的使用工况。同时基于数值模拟对该结构的振动效果进行了验证，将钻进时钻头与岩石的相互作用简化为简谐荷载，对双向回转钻具整体结构进行谐响应分析。结果显示，相比于普通单向回转钻进结构，同等条件下双向回转的钻具结构能够有效抑制扭转振动。

Abstract:

Vibration during drilling can cause fatigue failure and damage to the drilling tool. In order to improve the stability of downhole drilling tool， the author designed a drilling tool structure that relies on the planetary gear system to drive contra rotation of two coaxial bits. The strength verification of its core parts such as gears， seals， bearings， proved that the design strength of the structure can meet the normal working conditions. The vibration effect of the structure has been verified by numerical simulation， where the interaction between the drill bit and rock was simplified as harmonic load to perform harmonic response analysis to solve the vibration of the structure. Compared with the conventional drill structure， the result shows the coaxial contra-rotary drilling tool structure can effectively suppress twisting vibration under the same condition.