Study on the Influence of Network Characteristics of Artificial Main Fractures and Natural Fractures on the Effectiveness of Acid Fracturing

Carbonate reservoirs typically develop natural fractures, which significantly impact the effectiveness of acid fracturing processes. This study integrates the two-scale continuum model (TSC) and the embedded discrete fracture model (EDFM) to develop an acid fracturing simulation program for heterogeneous carbonate reservoirs using the open-source software FMOT. Key findings include the following. Under identical acid content conditions, the higher permeability of artificial main fractures results in longer wormholes. Natural fractures intersecting with the main fracture enhance local acid filtration and promote the formation of wormhole branches; the higher the fracture density, the more branches are formed within the wormholes. The higher the permeability of the main fracture, the less significant the influence of natural fractures on wormhole morphology. These results demonstrate that optimizing the permeability of artificial main fractures and effectively utilizing natural fracture networks can significantly enhance the effectiveness of acid fracturing.