垂直钻井工具测斜仪精确校正理论与实验

Theoretical and experimental study on precise calibration of the inclinometer in vertical drilling tools

针对自动垂直钻井工具因测斜仪(其核心部件为二轴或三轴重力加速度计)的安装误差而导致小井斜测量精度不高的问题,通过建立测斜仪的实际安装坐标系与其理想坐标系之间的映射关系,推导出利用测斜仪的实际输出信号计算真实井斜角的函数关系,从而在理论上实现了对测斜仪的精确校正。对基于二轴重力加速度计的测斜仪提出了只需要获取测斜仪的两个测量轴与其理想坐标系对应轴的夹角参数,即可对测斜仪进行精确校正的工程方法,并借助自行研发的某型号自动垂直钻具原理样机,对相应夹角参数提取及测斜仪的精确校正进行了实验分析。实验结果表明,利用该方法对测斜仪进行校正可保证测斜仪的测量精度不受测斜仪安装误差的影响。

The automatic vertical drilling tool may have a poor precision problem in small deviation survey due to an installation error of the inclinometer, of which the core component is a gravity accelerometer with two or three axes. Through the establishment of an image correlation between the actual mounting coordinate system of the inclinometer and its ideal coordinate system, we deduced a function to calculate the real angle of inclination by using actual output signals of the inclinometer and theoretically achieved the preci- sion calibration of the inclinometer. As for the inclinometer based on a gravity accelerometer with two axes, we proposed an engi- neering method for accurate calibration only by obtaining included angle parameters between the two measuring axes of the inclinome- ter and the corresponding axes of the ideal coordinate system. In addition, corresponding included angle parameters and the precision calibration of the inclinometer were experimentally examined by using the schematic prototype of a certain automatic vertical drilling tool self-developed recently, which showed that the application of this approach to calibrating the inclinometer can ensure the measur- ing accuracy free from the influence given by installation errors of the inclinometer.