随钻单极子声波测井模式优化及远探测*

针对非均匀性地层地质力学评价和地质导向钻井的需要，研究了随钻单极子声波的方位特性和反射声场特征，并研制了随钻声波测量装置。建立了不同方向速度模型井和反射声场模型，数值模拟了两个模型的单极子声波传播特征，使用单极子声源发射和偏极子接收器接收的测量模式，分别获得了波速周向变化图和反射波的方位特征。模拟结果表明，纵波对地层方位特性更容易提取和观测，反射波具有一定方位性。在水池里开展了随钻单极子声波远探测实验，利用反射波能够准确测量到1.00 m、3.00 m、5.00 m和7.00 m的反射界面距离，实验证明，在合适尺度范围内进行声波远探测是可行的。研究结果表明，随钻单极子声波测井技术在测量模式上进行适当的改进，对测井数据进行适当的处理，则这项技术既可以用于近井壁地层的非均匀性分析，又可以用于远井壁地层的界面探测，从而在随钻测井评价和钻井高效施工等方面发挥更大的作用。

Study on azimuthal and remote detection performanceof monopole acoustic LWD

For anisotropic formation geomechanics evaluation and geosteering drilling, azimuthal and refection wave field performance of monopole acoustic LWD is studied, and an acoustic LWD device is developed. Establishing borehole model with different velocity at direction and refection wave model, numerically simulating monopole acoustic propagation characteristics for the two models, monopole acoustic source and eccentric receivers are used to get borehole imaging with acoustic velocity and azimuthal refection wave characteristics. The simulation result shows that compressional wave is much sensitive to azimuth, however, shear wave is less sensitive to azimuth, furthermore, reflection wave is some sensitive to azimuth. Some experiments are carried out in a water tank to check remote detection performance of monopole acoustic LWD, which measuring the distance of reflection interface by reflection wave, the distance are set as 1m, 3m, 5m and 7m in different experiment, the experiment results show that it is feasibility to acoustic remote detection in proper range scale. The research result shows that monopole acoustic LWD can be used to evaluating anisotropic formation near borehole and remote detection of interface formation far from borehole, which is improved in measuring mode and data processing, thereby, it can play a greater role in LWD evaluation and high efficient drilling.