Three-dimensional fine characterization and numerical simulation methods for fractured vertical wells

To model the complex three-dimensional fracture morphology and spatial seepage characteristics formed after fracturing, a novel method for accurately representing three-dimensional fractures is introduced. First, computer-aided design (CAD) techniques are used to construct three-dimensional geometric model of the fractured vertical well and clarify the spatial geometric relationship among fractures, reservoirs, and wells, etc. Second, a 3D semi-structured grid node constraint algorithm and mesh generating method are proposed based on the complex geometric shape of the 3D fractures, their intersection with the wellbore, and their spatial seepage characteristics; and hence a mixed discrete solution method is implemented. Finally, the proposed method is used to simulate an actual fractured vertical well, of which the bottom-hole pressure and the characteristics of spatial pressure distribution are analyzed, and a set of inversion parameters for reservoir and fractures is obtained. The results indicate that the 3D fracture geometry significantly influences the spatial pressure distribution of well P, with noticeable non-uniformity in the vertical pressure distribution. The research helps in understanding the impacts of the 3D fracture morphology on the bottom-hole pressure and spatial flow characteristics during the fracturing process, thus improving the production of complex fractured wells.