Identifying thinly bedded reservoirs is important in exploration, appraisal, and development. The thin beds that we are referring to are of meter scale or less. Conventional seismic attributes are not able to resolve thin-bed effects. A new frequency-dependent amplitude variation with offset (FAVO) seismic attribute is developed for the prediction of thin beds. It is based on seismic wave scattering theory for vertically inhomogeneous media, in which the seismic response from a laterally homogeneous interval is represented by the Born series. The Born series characterizes the P-P and P-SV wave reflections, transmissions, and interbed multiples within the target interval with different order terms. The newly derived attribute corresponds to the second-order term of the Born series, in which P-S wave reflection and transmission energy is taken into consideration, and it is called the second-order FAVO gradient attribute. In a thinly bedded interval where sand/shale interfaces are abundant, the P-SV wave mode conversions are numerous. This leads to a strong second-order FAVO gradient attribute response compared to that of a blocky sand, silt, or shale interval under the assumption that there is no significant rock- and fluid-property differences between the intervals. Therefore, the new seismic attribute has the potential to be a thin-bed interval indicator. We have adopted a strategy to estimate the new attribute using conventional P-wave seismic data. The attribute is extracted from seismic data at the frequency range at which the second-order scattering effect is the most prominent. Synthetic and field data examples from offshore Trinidad are studied to demonstrate the second-order scattering effect and the potential usage of the second-order FAVO attribute for thin-bed reservoir characterization.

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频率相关的 AVO 分析：用于薄层识别的潜在地震属性

识别薄层储层在勘探、评价和开发中很重要。我们所指的薄床是米级或更小。传统的地震属性不能解决薄层效应。开发了一种新的随偏移距变化的频率相关振幅变化 (FAVO) 地震属性，用于预测薄层。它基于垂直非均质介质的地震波散射理论，其中来自横向均质层的地震响应由 Born 级数表示。Born 级数以不同阶项表征了目标区间内的 PP 和 P-SV 波反射、传输和叠层多次波。新导出的属性对应Born级数的二阶项，其中考虑了 PS 波的反射和透射能量，称为二阶 FAVO 梯度属性。在砂/页岩界面丰富的薄层层段中，P-SV 波模式转换很多。在假设层段之间没有显着的岩石和流体性质差异的情况下，这导致与块状砂岩、粉砂岩或页岩层段的二阶 FAVO 梯度属性响应相比。因此，新的地震属性有可能成为薄层间隔指标。我们采用了一种使用常规 P 波地震数据估计新属性的策略。该属性是从地震数据中二阶散射效应最突出的频率范围内提取的。