随钻正脉冲测井仪压力信号生成特性研究

Research on the generation characteristic of pressure signal of the positive pulse measurement with drilling system

随钻正脉冲测井仪压力波信号的强度决定了井下数据传输速率和传输距离。为了提高信号传输速率、确保信息传输准确、提高传输距离,需要对信号发生单元进行优化,以此来提高正脉冲信号强度。以旋转阀正脉冲测量仪为研究对象,利用计算流体力学(CFD)方法,对旋转阀压力信号进行仿真分析,研究了不同工况下钻井液流量和定、转子轴向间隙对脉冲信号强度的影响规律,并通过实验验证了压力波信号的特性。研究结果表明:压力信号幅值随着轴向间隙的增大而减小;增加钻井液流量可以提高信号强度,当钻井液流量由10L/s增大为35L/s时,流量的大小对压力信号幅值影响很大。

The pressure signal strength of the positive pulse measurement with drilling system determines the transmission rate of the downhole data and its transmission distance.In order to improve the transmission rate of the pressure signal,ensure the accurate transmission of information and improve its transmission distance in the logging with drilling technology,the signal generator should be optimized in design so as to improve the strength of positive pulse signal.With the rotary valve positive pulse generator as the study object,the computational fluid dynamics （CFD） method is used to conduct the simulation analysis of rotary valve pressure signal.The drilling fluid flow rate and the effect of axial gap between stator and rotor upon the laws of pulse signal strength is studied under the different industrial operation conditions,and the characteristics of pressure wave signals are tested via experiments.The results from the research indicate that the pressure signal amplitude value decreases with an increase in the axial gap between stator and rotor,and that an increase in drilling fluid flow can improve the signal strength and when drilling fluid flow increases from 10 L/s to 35 L/s,the magnitode of drilling fluid will have a great impact upon the pressure signal amplitude value.