用三维时域有限差分法研究随钻声波测井仪器隔声体的设计

Designing Isolator of Logging-While-Drilling Acoustic Tools Using Three-dimensional Finite-difference Time-domain Method

在柱坐标系中,利用三维时域有限差分方法研究了随钻声波测井仪器的隔声体设计。结果表明,不同结构的隔声体对钻铤纵模式波的时延量和隔声量存在很大差异。一种由周期性交错排列的凹槽构成的隔声体,相比于由圆环形凹槽构成的隔声体,具有更好的隔声效果。

Based on the first order velocity-stress scheme on staggered grids, a three dimensional （3-D） finite-difference time-domain （FDTD） is applied to numerical study the designing of isolator of Logging-While-Drilling （LWD） acoustic tool in cylindrical coordinates. Simulation results show that different periodic grooved isolators vary widely in delaying and attenuating the tool waves which propagate along the tool. A type of isolator with staggered grooves is proposed for better performance.