方位AVO技术检测储层各向异性的方法和实践

油气储层的各向异性是制约勘探开发的关键因素，在弱各向异性的前提下，可以利用地震资料振幅随方位角的变化对地下介质的各向异性做出相对准确的预测。为了搞清研究区储层的各向异性特征及其对储层开发的影响，利用研究区宽方位角高精度三维纵波地震资料对研究区储层的各向异性特征进行了预测；为了减小噪声对预测结果的影响，首先对地震道按不同的方位角范围进行叠加和偏移，然后利用不同方位角的处理结果对储层的各向异性特征进行预测；为了提高预测结果的精度和可靠性，对保持振幅处理的几项关键技术进行了讨论。实验结果显示，目的层反射具有明显的振幅随方位角变化的基本特征，各向异性预测结果与综合地质分析和钻井资料解释结果具有很好的吻合性，为下一步的开发井位部署提供了依据。

The Method and Practice of Detecting Reservoir Anisotropy with 3-D P-wave Azimuth AVO

Anisotropy is a key factor in the exploration and development of the oil/gas reservoir. Based on the theory of weak anisotropy, anisotropy of subsurface media can be approximately predicted on the seismic amplitude variation with azimuth. The paper predicted anisotropic properties of the reservoir in the study area with high fidelity wide azimuth 3-D P wave data. The seismic data are stacked and migrated in different azimuth ranges to decrease the effects of the noise on the prediction results, and anisotropic properties of the reservoir are predicted on the basis of the processing results analysis of different azimuth. The key techniques concerning amplitude-preserved processing were discussed to improve the accuracy and reliability of the predicted results. The test result showed that the reflection amplitude of the target horizon varies obviously with the azimuth, and the predicted anisotropic intensity is much consistent with the results of integrated geologic analysis and the drilling data, and the prediction result can be guidance for further deployment of the exploitation wells. (Financed by the 973 Program project, No. 2002CB211707)