Reliably estimating reservoir parameters is the final target in reservoir characterisation. Conventionally, estimating reservoir characters from seismic inversion is implemented by indirect approaches. The indirect estimation of reservoir parameters from inverted elastic parameters, however, will produce large bias due to the propagation of errors in the procedure of inversion. Therefore, directly obtaining reservoir parameters from prestack seismic data through a rock-physical model and prestack amplitude variation with offset (AVO) inversion is proposed. A generalised AVO equation in terms of oil-porosity (OP), sand indicator (SI) and density is derived by combining a physical rock model and the Aki–Richards equation in a whole system. This makes it possible to perform direct inversion for reservoir parameters. Next, under Bayesian theorem, we develop a robust prestack inversion approach based on the new AVO equation. Tests on synthetic seismic gathers show that it can dramatically reduce the prediction error of reservoir parameters. Furthermore, field data application illustrates that reliable reservoir parameters can be directly obtained from prestack inversion.

中文翻译：

---

来自叠前地震数据的储层参数直接反演

可靠地估算储层参数是储层表征的最终目标。传统上，通过地震反演来估计储层特征是通过间接方法实现的。但是，由于反演过程中误差的传播，根据反演的弹性参数间接估算储层参数会产生较大的偏差。因此，提出了通过岩石物理模型直接从叠前地震数据中获取储层参数，并提出了带偏移的叠前振幅变化（AVO）反演方法。通过组合物理岩石模型和Aki–Richards方程在整个系统中，得出了一个基于油孔隙率（OP），砂眼指示剂（SI）和密度的广义AVO方程。这使得可以对储层参数进行直接反演。接下来，根据贝叶斯定理，我们基于新的AVO方程开发了一种鲁棒的叠前反演方法。对合成地震道的测试表明，它可以显着降低储层参数的预测误差。此外，现场数据应用表明，可以从叠前反演直接获得可靠的储层参数。