Abstract:  The near bit engineering parameters are important factors which can affect drilling safety. With the advances of drilling technologies, such as ultra-deep well technology and extended reach drilling technology, the engineering parameters measured on ground, like weight on bit ( WOB) and torque on bit ( TOB) , can’t mirror the actual downhole working conditions anymore. Downhole engineering parameter measurement system is the main way to obtain related downhole parameters. In this paper, the development status of downhole engineering parameter measurement system at home and abroad is summarized at first, then in order to obtain the true motion state of downhole drillstring, engineering parameter measurement system is developed based on strain measurement principle and sensor theory,and the measurement system is validated by laboratory experiment and field application. The measurement system can be installed either near the well bottom or at any position along the
BHA to record WOB, TOB, vibration, pressure and temperature. By the recorded downhole engineering data, the theoretical mechanical model correction, downhole working condition explanation and drilling accidents prediction can be achieved. The field application proves that the measured parameters are accurate to reflect the actual working conditions and the system performs stable and reliable for at least 150 hours, which can provide strong support for drilling operations. In the future, the utilization of massive downhole measurement data shall be strengthened to accurately determine the operating condition sunder ground, reducing the drilling risks.

Key words:  , engineering parameter, measurement system, downhole working condition, WOB, torque, vibration

摘要：  近钻头处的工程参数是影响钻井安全的重要因素。随着超深井、大位移水平井等技术的发展，地面测量的钻压、扭矩等工程参数已经不能反映井下的实际工况，而井下工程参数测量系统是获得井下相关参数的主要途径。文章首先对井下工程参数测量系统的国内外发展现状进行了梳理与总结；然后为了获得井下钻具的真实运动状态，基于应变测量原理和传感器理论，研制了井下工程参数测量系统，并通过室内实验和现场应用实例验证了该测量系统。该系统既可以安装在井底近钻头处，也可以沿底部钻具任意位置分布，能够测量钻压、扭矩、振动、压力和温度。借助测得的数据，可以修正理论力学模型，解释井下工况，预防钻井事故。应用效果证明，该测量系统测量参数准确，能够真实反映井下实际工况；系统性能稳定可靠，在井下的工作时间可达１５０ｈ，满足现场作业要求，可为钻井作业提供有力的支持。

关键词:  , 工程参数, 测量系统, 井下工况, 钻压, 扭矩, 振动