井下高温对内含钻井液钻柱振动固有特性的影响分析

ANALYSIS OF THE DOWNHOLE TEMPERATURE AFFECTION ON THE INHERENT VIBRATION CHARACTERISTICS OF THE DRILLSTRING CONTAINING DRILL FLUID FLOW

本文分析了考虑内有钻井液流体流动时井下温度变化对钻柱振动固有特性的影响问题.首先,文中推导出了内含流动钻井液的钻柱振动固有频率表达式;然后,从温差效应对钻柱本体材料性能影响与内含钻井液流体性能影响两个方面,进一步分析了井下高温对钻柱振动固有特性所带来的变化及估算问题;最后,文中还给出了温度影响下的井下钻柱振动段固有频率的简便估算方法及实际例算.

In the paper, the downhole temperature affection on the inherent vibration characteristics of the drillstring containing flowing drill fluid is analysed. The mathematical formula for inherent vibration frequency of the drillstring containing flowing drill fluid is derived. The calculation and change of the inherent vibration characteristics with rise in downhole temperature, are studied from two aspects : heat effect on drillstring itself and on drill fluid flow. A handy estimating method and a practical computing example of the eigen frequency of the vibration drillstring section influenced by the downhole temperature are presented.