Application of 3D Embedded Discrete Fracture Model for Simulating CO₂-EOR and Geological Storage in Fractured Reservoirs

For greenhouse gas control and environment protection, CO₂ emission reduction has become a hot spot in global research. CO₂ injection in developed oil reservoirs to enhance oil recovery is widely regarded as one of the most economical and promising measures for reducing anthropogenic CO₂ emissions into the atmosphere. In this paper, a three-dimensional embedded discrete fracture model is proposed and applied to simulate CO₂ flooding and geological storage processes in hydraulically fractured reservoirs. The gas injection is simplified as a two-phase two-component mathematical model with the varying pressure-related fluid physical properties, and its accuracy is verified by commercial software tNavigator^®. The advantage of this model is that it can deal with the complex geological conditions of three-dimensional arbitrary-inclined fracture networks and accurately assess the effects of CO₂-EOR and geological sequestration in real reservoirs. Two application cases of CO₂ huff-and-puff with a single well and inter-fracture asynchronous injection and production are demonstrated and explained in detail. The optimized technological parameters and CO₂ saturation distribution can provide key technical parameters for field operations.