钻井液阻尼对钻柱动力失稳的影响

人们研究钻柱动力失稳时,往往忽略钻井液阻尼的影响,实际上钻井液阻尼对钻柱的振动是一个极其重要的影响因素。据此,研究了钻井液阻尼对钻柱动力失稳的影响。推导出钻井液阻尼时钻柱动力失稳区域的计算公式,讨论了钻柱动力稳定性与钻压及钻柱长度的关系。实例分析表明,钻井液阻尼有利于提高钻柱的动力稳定性,钻井液的流速越大,钻柱动力稳定性就越好,其失稳区域越小;钻压越大,钻柱越长,钻柱的动力稳定性就越差,其失稳区域就越大。

Influence of drilling fluid damp on dynamic destabilization of drill stem

Drilling fluid damp is an important factor influencing the vibration of drill stem. The influence of drilling fluid damp on dynamic destabilization of the drill stem is investigated. The equation for calculating the area of dynamic destabiliza tion of the drill stem with drilling fluid damp is derived, and the relationship between the drill stem stability and bit load and drill stem length is discussed. Analysis shows that, drilling fluid damp is helpful to improving the dynaxnic stability of the drill stem, the higher the flow rate of foe drilling fluid, the better the drill stem's dynamic stability, and the smaller the area of the destabilization; the larger the bit load and the longer the drill stem, the worse the drill stem's dy namic stability, and the larger the area of destability.