175℃条件下近钻头随钻测井几何导向技术研究

In recent years, with the ongoing increase of the oil well, especially the horizontal oil well around the world, the continued increase in demand for advanced at-bit logging-while-drilling (LWD) equipment is great. However, this kind of product is almost monopolized by foreign companies..In order to solve the challenge of meeting the needs of the equipments in China, the project mainly carries on the study of geometric orientation unit of geosteering device that can be used in at-bit LWD at a extreme temperature of 175℃. The key contents of the study are as follows:.1) Serious screening the magnetic sensors, acceleration sensors, and the general electronic components to meeting the high temperature conditions; Testing their electrical characteristics by experiment, and studying out the temperature coefficient compensation law;.2) Improving error calibration of the magnetic and acceleration sensors and correcting algorithms; Studing on the calibrating operation;.3) Proposing a filtering algorithm to achieve useful signals from the magnetic and acceleration sensors under the conditions of strong vibration and high-speed self-rotating;.4) Improving the performances of complex mathematical calculations in embedded processors and reducing the computational time to make calculating speed suitable for application requirements..Based on this study, we hope to get the performance indicators of the design as: working temperature of -30~175℃, inclination angle accuracy of 0.5°，azimuth accuracy of 2.0°, and tool face angle precision of 1.0°..The successful study of the project will be useful to promote the technology in our country close to the international advanced level .In addition, the complete research has important practical significance and valuable reference for designing other equipments used by at-bit LWD.

近年来全球钻井数量，尤其是水平井数量持续增加，对高精尖的近钻头随钻测井仪器需求不断上升，而这类产品的核心技术基本被国外垄断。本项目着眼于国内客观需求，提出研究能工作于175℃的近钻头随钻测井几何导向装置，重点研究内容有：1）高温条件下磁场和加速度传感器以及通用电子元器件的筛选，标定温度与信号输出特性的规律，测试其电学特性；2）改进磁场和加速度传感器的误差标定和校正算法，给出标定操作方法； 3）提出高振动和自旋运动条件下磁场和加速度传感器输出信号的滤波处理方法，有效提取有用数据； 4）改进复杂数学运算的实现方法，减少嵌入式处理器的计算时间。本项目设计的解决方案拟达到工作温度范围-30~175℃，倾角观测精度0.5°，方位角观测精度2.0°，工具面角观测精度1.0°的性能指标，与国际先进水平相当。本项目若顺利完成，将会对近钻头随钻测井其他装备研发提供有益参考。

本项目研究使用磁强计和加速度计来进行姿态解算，解决几何导向过程中的误差补偿和校正问题、姿态融合和滤波问题，选用合理的传感器和电子元件，并设计机械结构，实现。.项目研制了一套样机，实现了将三轴磁通门传感器和三轴石英加速度传感器组合起来测量姿态，主要研究进展和成果包括：1）建立了可工作在175℃的几何导向硬件平台，包括高温高精度姿态测量传感器、高温高精度数据采集、处理和存储电路、设计并加工了符合国际主流设计的结构骨架。2）建立了175℃的下传感器温度效应补偿和安装误差校正方法，包括2次方传感器温度补偿算法和一套转台多位置的传感器安装误差标定方法。