近钻头工程参数测量短接结构设计与误差分析

Structural design and error analysis of a device for measuring drilling engineering parameters near the bit

为了准确测量近钻头处的钻压扭矩等工程参数,利用材料力学的相关知识,定量分析了近钻头工程参数测量短接实际工况下的应力与应变特征,据此确定了测量短接传感部分的基本结构参数。使其既能保证钻井安全,又能提高测量信号的机械放大倍数,降低了微弱信号检测的难度。利用误差理论分析了影响测量短接误差的主要原因,并对应变片粘贴误差与测量短接内外压力影响进行了定量分析与计算,为应变片粘贴精度要求、测量短接内外压力影响的在线补偿等实际测量问题的解决提供依据。

In order to improve the measurement accuracy of drilling engineering parameters near the bit,the strain and stress of the measurement device in practile conditions were studied based on the Mechanics of Materials.There are two aims for the analysis,one is to obtain the structural parameters of the measurement device,the other is to improve the mechanical amplification for weight on bit and torque on bit,and to reduce the degree of difficulties of weak signal detections on the condition of drilling safety.The facts which have influences on measurement errors,especially for the stain gauge positioning errors and the inside and outside pressure effects were analyzed.The analyzed results can be used to determine the request accuracy for strain gauge positioning and online error correction caused by the pressure effect of inside and outside of the measurement device.All of these are essentially necessary for putting this technique into practice.