Abstract:
Fracture parameters, such as fracture density, orientation, and filling, play critical roles in engineering fields. In hydrocarbon exploration, the prediction technology for fracture parameters based on five-dimensional seismic data has the advantages of wide prediction range and high resolution and has attracted considerable attention in recent years. Therefore, based on the introduction of equivalent anisotropic petrophysical theory of fractured reservoir in the first section (Ⅰ), we will review five-dimensional seismic prediction methods for fracture reservoirs with different complexities focusing on two aspects: ellipse fitting analysis and fracture parameter prediction based on equivalent anisotropic petrophysical theory. Regarding the first aspect, the AVO gradient ellipse fitting and Young's modulus ellipse fitting methods were summarized. The AVO gradient ellipse fitting is simpler than the Young's modulus ellipse fitting, but the prediction result of the latter is more stable than that of the former. In addition, based on the differences in petrophysical theories, the development status of prediction technology for fracture density, orientation, and fluid distribution using five-dimensional seismic data at home and abroad is summarized from three perspectives. On this basis, an example of fracture parameter prediction in gas-bearing shale reservoirs in southwest China is provided. With increasing difficulties in reservoir characterization, we should pay attention to the decoupling of model parameters in complex strata, more feasible and stable methods of model parameterization, and the construction of forward and inversion algorithms in the future to improve the prediction accuracy of fracture parameters. At the same time, the inversion theory of strongly anisotropic media should be explored further in the future.