用双分量记录反演裂隙方位的旋转变换方法

Rotation transform for inversion of the azimuth of fractures with bicomponents record

地矿部石油物探研究所, 南京210014

Research Institute of Geophysical Prospecting for Petroleum, Nanjing 210014

沉积岩中的定向直立裂隙系是一种方位各向异性体, 它往往是油气富集区, 是地球物理工作者寻找的重要目标之一。横波在这种定向直立裂隙系中传播会引起分裂, 产生快横波和慢横波, 因而可通过纯横波资料或三分量转换PS波资料来检测这种所谓的横波双折射。通常的检测办法是进行快慢波分离技术。本文介绍旋转变换技术, 并给出一种求取裂隙走向方位角的算法。通过合成记录和实际资料检验, 说明本算法是正确有效的。

The system of the aligned vertical fractures in sedimentary roeks is usually a zone of rescrvoir and one of important objectives to be found by gcophysicists. Becausc these vertical fractures can cause shcar waves to split and generate fast-shear-wave and slow-shear-wavc when the shear waves travcl through them. This so-called shear wave bircfringence can be detected with constant mode shear wave data or tricomponent-converted PS data. The traditional dctection method is the separation of the fast-shear-wave from the slow-shear-wave using a rotation technology. This paper will introduce the rotation transform technology and prescnt an algorithm for calculating the trend azimuth angle of the fractures. The examples of synthetic and real data given show that the algorithm is correct and effective.