气体钻井过程中地层出水的微波随钻监测方法

A Microwave-based Monitoring while Drilling Method for Formation Water Production in Gas Drilling

针对目前气体钻井过程中地层出水预测方法不够完善,往往导致预测结果滞后,尤其是在刚钻遇水层或地层微量出水时难以准确判断井下出水状况,提出了一种基于微波技术的随钻监测气体钻井地层出水的新方法,依据微波谐振腔的微扰原理,通过测量微波谐振腔的谐振频率偏移,以实现对空气钻井过程中返出气体湿度的连续在线监测,并根据气体钻井现场工况,对微波谐振腔传感器进行优化设计。室内模拟试验表明,该项监测技术测量结果同实际值基本相符,误差约为7%,且具有灵敏、连续及操作方便等优点,能够及时有效地反映返出气体的湿度变化,表明提出的监测技术是可靠的,且具有一定的现场参考价值。

A new monitoring while drilling( MWD) method based on microwave technique was proposed to solve the problem that the current MWD method was not accurate enough to predict the trend of formation water production during the gas drilling promptly,the predicted result was often delayed,when the water layer was first encountered in drilling or when the amount of water production was small. Based on the microwave cavity perturbation theory,it can continuously monitor the humidity of backflow gases on-line during the gas drilling by measuring resonant frequency shift of the cavity,as well as optimize the design of microwave cavity sensor according to the operation conditions in the gas drilling field. The laboratory simulation experiments show that the results of new MWD method are basically consistent with that of actual value with an error about 7%,and it can reflect the changes of airflow humidity timely and effectively with advantages of sensitivity,continuity and easy operation. It is presented that the new MWD method is reliable and provides certain reference for the oilfields.