Characteristics of Rupture Development and Prediction Methods in the Central Sichuan Basin, China

Abstract

Middle and deep faults are developed in the Sichuan Basin-Chuanzhong area, and the spatial structure of the faults is divided into three parts: fault core, fracture zone, and induced fracture zone. The fracture zone is the fracture space formed when the rock is crushed by more than the strength limit stress, the fault core is the area which is filled with muddy and small rock fragments in the late stage of the stress damage at the center of the fracture zone, and the induced fracture zone is the area developed when the surrounding rock is affected by the stress on the two sides of the fracture zone. The induced fracture zone is the area where a large number of fractures are developed in the surrounding rocks on both sides of the fracture zone under the influence of stress. The study shows that the carbonate fracture zone is a favorable part for the development of reservoirs with seam and hole bodies, and the identification and prediction of fracture development zones are of great significance for the selection of oil and gas well locations. From the core of the fault, the fracture zone to the induced fracture zone, from the core to the outside, the difference in the degree of fracture development causes changes in logging and seismic response characteristics, such as the gradual decrease of natural gamma/neutron, the gradual increase of density/velocity/resistivity value/permeability, and the seismic data amplitude weakening, frequency increasing, and waveform changing. This paper makes use of log data interpretation, seismic attribute preference, multi-attribute fusion, and fracture-solution inversion to form a set of technical series for identifying fracture zones by geophysical methods, which will lay the foundation for the next step of fine prediction demand for exploration and development in the central Sichuan area.