南黄海多道地震处理中深层Q值补偿实验

The gas reservoirs in the middle-deep layer of the South Yellow Sea have been reformed and destroyed during the multi period tectonic movement. The underground geological structure is complex. The quality of seismic profile in the middle-deep layer is poor. It is difficult to obtain the effective information of strata using the conventional seismic energy compensation technique, which restricts the research of tectonic structure and gas exploration in the middle-deep layer of the South Yellow Sea. Based on this, the project put forward a new method that the seismic attenuation mechanism based on rock physics combined with the formation Q value compensation in the time-frequency domain, which pertinently solve the question. Firstly, obtain the effect of rock on seismic wave attenuation by laboratory core testing, namely attenuation relationship with porosity、 saturation、 lithology, etc.. Then use the method of rock physics to obtain the relation of the seismic rock physics parameters, and in view of the middle-deep layer in the South Yellow Sea, establish the measuring plate of the earthquake parameters – lithology, in order to analyze and obtain the seismic attenuation mechanism in the middle-deep layer of the South Yellow Sea. Based on this, use the method of prestack formation Q value extraction in S domain to obtain the formation Q value and derive the seismic wave propagation equation in the actual medium. Finally, do the Q value compensation in the time-frequency domain, which improve the resolution of seismic data, obtain the effective information of the middle-deep layer, and serve the study of tectonic structure and oil and gas exploration in the middle-deep layer of South Yellow Sea.

南黄海中深层油气藏经历了多期构造运动的改造和破坏，地下地质结构较为复杂，地震剖面的中深层地震资料品质较差，常规的地震波能量补偿技术很难获得有效的地层信息，从而制约了南黄海中深层构造结构研究及中深层油气勘探。基于此，本项目提出了基于岩石物理的中深层地震波衰减机理与时频域地层Q值补偿相结合的方法，即针对性解决问题的方法。首先通过实验室岩心测试得到岩石对地震波衰减的影响，即衰减与孔隙度、饱和度、岩性等的关系，然后利用岩石物理方法得到岩石的地震参数之间的关系，并针对南黄海中深层，建立相应的地震参数-岩性关系量板，以此分析得到南黄海中深层地震波的衰减机理。在此基础上，利用基于S变换的叠前地层Q值提取方法提取地层Q值并推导地震波在实际介质中的传播方程，最后进行时频域地层Q值补偿，提高地震资料分辨率，获得中深层有效的地层信息，为南黄海中深层构造结构研究及中深层油气勘探服务。

南黄海中深层地质结构较为复杂，地震资料品质较差，常规的地震波能量补偿技术很难获得有效的地层信息，基于以上情况，本项目采取了基于岩石物理的中深层地震波衰减机理与时频域地层Q值补偿相结合的方法。首先利用岩石物理的方法研究了南黄海中深层地震波衰减机理，以此来指导地层Q值的提取和地层Q值的补偿。地层Q值提取采用的是基于S变换的地层Q值提取方法，该方法的优势在于一方面叠前地震资料含有更加丰富的地层信息，一些细微的地层特征在叠后地震资料中是看不到的；另一方面S变换具有更高的时频分辨率，可以充分考虑因地层吸收而引起的振幅、频率等信息的变化，而且避免了通常品质因子计算中的平均效应；最后归零处理消除了偏移距的影响，得到更加精确的地层Q值。在此基础上，推导了地震波在实际介质中的传播方程，并进行了时频域地层Q值补偿，补偿了地震波的振幅和相位，提高了地震资料分辨率，改善了地震资料的品质，获得了中深层有效的地层信息，从而用来指导南黄海中深层构造结构研究及中深层油气勘探。

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