Research on Joint Identification of Basement Faults by Gravity, Magnetic and Seismic Technologies in Sichuan Basin

Summary The study of Pre-Sinian basement faults is of great significance for oil and gas exploration in Sichuan basin because basement faults not only control the deep to ultra-deep palaeo structural evolution, tectonic features, and distribution of sedimentary facies, but also are main factors of deveopment of middle-deep Permian volcanic rocks reservoirs and favorable facies. However, the Pre-Sinian strata in the Sichuan Basin experienced complex tectonic movement and sedimentary evolution. Due to the limitation of many factors such as the less contrasts of rock physical properties, complex seismic wave fields, and low signal-to-noise ratios of seismic data, it was severely restricted that the accuracy of seismic imaging and interpretation of basement faults. In this study, ultra-deep low frequencywideband preserved technology and interbeded multiple wave suppression technology were used to improve the imaging of deep to ultra-deep low-frequency signals and the accuracy of in the migration imaging especially. Deep faults in the Lower Paleozoic-Sinocene Proterozoic strata can be effectively identified by using joint seismic and non-seismic interpretation technology, and the role of basement faults in controlling volcanic lithofacies is also discussed and explored, which provide the basis for the exploration and deployment of volcanic natural gas in Sichuan Basin.