基于多传感器数据融合的准垂直井眼轨迹动态测量方法研究

The measurement accuracy of borehole trajectory space attitude is the premise and foundation to the control of electronic vertical drilling system. At present, the measurement accuracy of the traditional methods deteriorates sharply when the drilling hole is nearly vertical, which seriously affects the intelligent judgment of the automatic vertical drilling system. Thus, it leads to the deviation of the real drilling trajectory from the preset trajectory. Therefore, this project will study the deterioration mechanism of inclination measurement accuracy under the condition of near vertical. This project will propose a new inclination measurement scheme based on the “Inertia + Magnetic” method which composed of accelerometer, flux-gate, gyro and other sensors. Firstly, the influence mechanism of the sensor installation error on the inclination survey accuracy will be researched and the on-line compensation and correction method of the installation error will be proposed. Secondly, under the condition of downhole working, the influence mechanism of the sensor random noise on the inclination survey accuracy will be studied. The characteristics of sensor random noise will be revealed and the sensor random noise model will be established. Finally, a new inclination measurement algorithm applicable to approximate vertical state will be studied in this project. In order to avoid the mathematical singularity, a new navigation coordinate system will be established. The novel navigation arrangement equation will be designed based on this new reference coordinate system. The research results of this project will enrich the inclination measurement theory and method, promote the automation and intelligent process of vertical drilling systems, and have important scientific significance and engineering application value.

井眼轨迹空间姿态的测量精度是保证电子式自动垂直钻井系统防斜打直的前提与基础。目前，传统的测斜方法在钻孔近似垂直的情况下测量精度急剧恶化，严重影响了自动垂直钻井系统对实钻井眼轨迹的智能判断，导致实钻轨迹偏离预设轨迹。本项目以提高准垂直状态下测斜精度为出发点，提出由加速度计、磁通门与陀螺等多种传感器数据融合为基础的测斜方案。首先研究传感器安装不正交误差对测斜精度的影响机理，提出不正交误差的修正方法，补偿由安装误差造成的测斜不准确度；其次，研究在动态测量条件下传感器随机噪声对测斜精度的影响机理，建立传感器随机噪声模型，抑制由随机误差造成的测斜不确定度。最后，为解决准垂直测斜算法出现奇异的问题，建立“新参考系”，设计测斜编排方程，将多传感器数据最优融合，提出适用于准垂直状态的高精度测斜算法。本项目研究成果将丰富测斜理论与方法，推动垂钻工具的自动化与智能化进程，具有重要的科学意义与工程应用

井眼轨迹空间姿态的测量精度是保证电子式自动垂直钻井系统防斜打直的前提与基础。目前，传统的测斜方法在钻孔近似垂直的情况下测量精度急剧恶化，严重影响了自动垂直钻井系统对实钻井眼轨迹的智能判断，导致实钻轨迹偏离预设轨迹。本项目以提高准垂直状态下测斜精度为出发点，提出由加速度计、磁通门与陀螺等多种传感器数据融合为基础的测斜方案。项目完成情况如下：.1.完成了基于MEMS多传感器的信号采集电路方案设计，并完成了基于MEMS多传感器的随钻测斜系统的硬件电路印制电路板的制作，完成了基于C++语言的人机交互界面设计。.2.针对MEMS-IMU的确定性误差，建立了MEMS传感器的误差模型，设计了六位置标定方法，并利用温控转台进行标定实验。实现了传感器的零偏误差、标度因数误差、安装误差的标定与补偿，提高传感器的测量精度。.3.针对MEMS-IMU的确定性误差，提出了基于改进Dijkstra算法的系统级标定路径规划方法，以可观测度分析为依据，并根据钻井领域特征，建立了30维卡尔曼滤波模型，提出了MEMS-IMU在线标定方案。该方法可以为不同标定条件、不同精度的MEMS-IMU构建最优系统级标定路径，大大缩短标定时间，并达到预定的目标精度。.4. 针对MEMS传感器的随机误差，针对经典Allan方差法不能分析MEMS陀螺仪噪声的动态特性，本课题提出了动态Allan方差的动态噪声分析法，分析了MEMS陀螺仪在振动条件下的噪声特性，并实现了噪声项幅值随时间变化的二维显示。研究了快速动态Allan方差法，不仅可以分析不连续数据的噪声特性，还提高了动态Allan方差分析数据的速度。利用DAVAR方法对MEMS传感器的振动数据进行动态分析，并建立噪声模型，应用于卡尔曼滤波噪声建模，提高了振动中钻孔轨迹的测量精度。.5.针对近垂直情况下测斜计算出现数学奇异的问题，本课题建立了“钻井坐标系”，重新设计了测斜算法，并进行了实验验证。结果表明：在一小时的实验时间内，井斜角和工具面角的测量误差约为0.1°，方位角误差约为0.2°，相比于传统地理系下的计算结果，其姿态精度有了大幅度的提升。