充气欠平衡钻井 MWD信号衰减原因分析与解决方法

充气欠平衡钻井中，井下随钻测量设备 MWD发射的钻井液脉冲在传播的过程中衰减程度很高，地面设备无法完成对井眼轨迹的监测与控制。通过建立充气欠平衡钻井 MWD信号传输模型，分析制约压力波信号传输的因素，提出调整地面接收器安装位置和改造注气方式两种解决方案并进行现场试验。结果表明:地面传感器的安装位置对信号接收没有影响；改造注气方式将气液充分混合后对信号传输有一定的改善作用，可以提升 MWD的有效测量距离。

Reason analysis and solve method to the attenuation of MWD signal in aerated underbalanced drilling

In aerated underbalanced drilling,the attenuation of the mud pluses emitting by the underground measure-while-drilling(MWD) equipment is at a high degree,and monitoring and controlling on well trajectory cannot be measured by ground receptor.By establishing the mathematical modelling of the MWD signal transmission and analyzing the reasons of restricting the signal transmission,two solutions were proposed and was followed by fieldtest which involve adjusting the installation site of the MWD ground sensor and transforming gas injection manner.The results show that the installation site of the MWD has no influence on the signal receiving,transforming gas in jection manner through fully mixing gas and liquid could slightly improve the signal transmission and enhance the effective measurement distance of MWD.