随钻四极子声波测井仪的设计及试验

Design and Experiment for a Quadrupole Acoustic LWD Tool

针对随钻单极子声波测井仪器无法随钻测量软地层横波速度的问题,设计了一种随钻四极子声波测井仪。该测井仪由Drilog;随钻测井系统、接收电路、扶正器、接收声系、隔声体、发射声系及发射电路组成。详细介绍了随钻四极子声波测井仪关键部件发射换能器、隔声体和接收声系的设计实现方法,并通过试验和模拟方法验证了这些关键部件的功能。该测井仪在新疆轮台KS3-B1Sa井进行了试验,测得了高质量单极子全波及四极子横波信号,且硬地层单极子全波中的横波时差与四极子横波时差吻合。现场试验表明,随钻四极子声波测井仪的功能达到了设计要求,可以随钻测量地层的横波速度,为准确评价地层提供测井数据。

Because the monopole acoustic logging while drilling (LWD) tool cannot measure the velocity of shear waves in soft formations while drilling,a quadrupole acoustic LWD tool (QUAST) was designed.This logging tool is composed of LWD System Drilog;,a receiving circuit,centralizer,receiving acoustic system,isolator,transmitting acoustic system,and the transmitting circuit.This paper introduces in detail the design method of the key technologies of the logging tool,such as the transmitting transducer,isolator and receiving acoustic system and verified their functions through experiment and simulation.The logging tool was tested in Well KS3-B1Sa in Luntai,Xinjiang,and high-quality signals of monopole full waves and quadrupole shear waves were detected.In hard formations,the time slowness in the shear waves of monopole full waves was consistent with that in quadrupole shear waves.The field test showed that the function of quadrupole acoustic LWD tool could meet the design requirements,and so as to measure the velocity of shear waves in the formation while drilling,and provide logging data for accurate formation evaluation.