基于四分量偶极横波远探测的井周构造走向快速反演方法研究

Research on a fast inversion method for structural strike around a borehole based on four-component dipole shear wave reflection imaging

偶极声源的辐射特性及仪器的四分量正交采集系统使得偶极横波远探测可在一维井筒中对井外构造进行方位探测.基于反射横波幅度随声源偏振方向呈余弦平方变化这一特征,本文提出一种利用函数拟合快速反演井周构造走向的方法.根据这一规律,该方法仅用4个方位剖面数据即可准确反演井周构造走向,同时得到井周构造的离井距离和倾角.数值模拟和物理实验模拟均验证了幅度随方位的变化以及反演方法的可行性.根据这一方法做的现场实例也进一步证明了该方法的适用性.本文工作为利用四分量偶极数据进行井周构造的反射横波成像提供了实用而有效的处理方法.

The directional radiation characteristics of the dipole source and four component acquisition of the tool allow dipole shear wave reflection imaging to determine the orientation of geological structures from the 1 D borehole.Based on the amplitude variation of the reflected shear waves with the source,we propose an efficient method for determining the strike of geological structures around the borehole.This method uses the reflection images of only four azimuths to determine the strike of structure,the distance from the borehole and dip of structure can be obtained by this method with only four azimuth profile data,The azimuthal variation characteristics of the reflection waves and the validity of the processing method are verified by both the theoretical modeling and laboratory experiment results.Examples of field data processing further confirm the application validity of the method.This paper provides a practical and effective processing method for determining the geological structures around the borehole using four-component dipole shear wave reflection imaging.