Structural heterogeneities in fault-controlled cavity carbonate reservoirs: Insights into fracture and fault patterns

Abstract

This study investigates the role of fault zones and fracture networks in controlling cavity distribution and fluid flow within carbonate rocks of the Tarim Basin using static and dynamic data. By integrating multi-attribute unsupervised seismic facies analysis, fracture network modeling based on ant tracking, and slip and dilation tendency analyses, we construct 3D models to characterize fault zone patterns, cavity distribution, fracture geometry, connectivity, and deformation behavior. The results demonstrate that fault zone patterns are the primary controls on cavity distribution, with cavity arrangements closely reflecting the orientations and densities of fracture networks in the DFN model. Extensive cavity geobodies are concentrated at fault zone intersections, where fractures exhibit increased density and connectivity. The large geobody, defined by considerable connected volumes, high permeability, and high production performance, is situated in these intersections with dense, highly connected fracture networks. These networks enhance fluid flow and shape fluid pathways, highlighting their role in cavity reservoir dynamics. These findings provide insights for improving reservoir modeling and optimizing injection-related geoengineering activities, such as acid stimulation and hydraulic fracturing.