基于叠前深度偏移的AVO反演在神狐海域试采区的应用

为了更好地研究神狐海域试采区天然气水合物的展布形态和赋存状况，基于高精度层析速度反演后的叠前深度偏移地震资料进行AVO反演技术研究。为在天然气水合物富集区有效地进行AVO研究，AVO处理前运用叠前深度偏移技术，通过高精度层析反演不断迭代速度模型；然后通过偏移来改善资料的质量，结合实测钻井资料进行AVO正演分析、反演可行性分析、属性交会分析；最后将具有高横向分辨能力的地震资料和高垂向分辨能力的测井资料与地质相结合进行叠前同时反演。该方法可反演出纵、横波阻抗等属性，直接进行岩性和流体识别，结果表明，在AVO反演中引入叠前深度偏移技术，为反演提供了较高质量的叠前共反射点道集和精细的层速度模型，改善了AVO技术在试采区的应用效果，提高了反演的可靠性。反演出的各种属性为AVO分析提供了丰富的信息，能够比较准确地反映地下水合物矿体的展布情况，可用于后续水合物储层的分析及综合研究，对未来的水合物勘探开采具有重要的现实意义。

Application of AVO inversion based on pre-stack depth migration in the test-mining area of Shenhu area, South China Sea

In order to better study the pattern and distribution of natural gas hydrates in the test-mining area of Shenhu area, this paper conducts an AVO (Amplitude Variation with Offset) inversion research based on PSDM (pre stack depth migration) seismic data after high-precision tomography velocity inversion. In order to effectively carry out AVO research in the area of natural gas hydrate enrichment, PSDM was used before AVO treatment, and high-precision tomography inversion continuously iterated the speed model before using migration to improve the data quality. The measured drilling data was used for AVO positive analysis, AVO inversion feasibility analysis, AVO attribute intersection analysis. Finally, the seismic data with high horizontal resolution, the logging data with high vertical resolution and geological information were combined to carry out simultaneous inversion and stack. This method can help P-wave and S-wave impedance inversion and lithologic and fluid identification. The results show that introducing PSDM in AVO inversion provides a higher quality pre-stack co-reflection point gather and a finer tomography speed model, improves the application effect of AVO technology in the test mining area, and improves the reliability of inversion. The various attributes of the inversion provide rich information for AVO analysis, which can accurately reflect the distribution and development of underground hydrate ores. The research result can be used for the subsequent analysis and comprehensive research of hydrate reservoir and is of practical significance for the future of hydrate exploration and exploitation.