Seismic Prediction of Multiscale Fracture in Archaean Buried Hill Gas Field

Bozhong B gas field is an Archean burial-hill fractured gas reservoir. The burial-hill in this area experienced multi-stage tectonic movement and multi-scale fractures were coupled in the reservoir. The conventional large-scale fracture prediction based on post-stack seismic data and the meso-scale fracture prediction based on prestack anisotropy analysis are both single, which makes it difficult to accurately predict the spatial distribution pattern of underground multi-scale fractures. In this study, (1) multiple pre-stack and post-stack methods were used to predict fractures at different scales, and a comprehensive fracture density field was obtained by random forest fusion. (2) The power law distribution relationship between fracture length and fracture number was defined based on seismic logging data statistics, so as to predict the development frequency of fracture scale at all scales in B gas field; (3) By extracting post-stack fault attributes and pre-stack prediction vectors, combined with FMI logging correction, a guidance field for fracture development direction was established. (4) Combined with fracture density field, fracture length frequency and fracture direction guidance field, multi-scale fracture distribution prediction of B gas field is realized. A set of technical flow for multi-scale fracture prediction of buried hill is formed, which provides technical support for the development of buried hill fractured gas field, effectively guides well location deployment, and has exploratory significance for subsequent multi-scale fracture seismic prediction research.