Integrated LSM-DFN Modeling of Naturally Fractured Reservoirs: Roughness Effect on Elastic Characteristics

摘要

Crack micro-geometries and tribological properties have a significant influence on the elastic characteristics of naturally fractured reservoirs. Numerical simulation as a promising approach for this issue still faces some challenges. For this purpose, we develop an integrated numerical scheme accounting for roughness effects by coupling a modified lattice spring model (LSM) with discrete fracture networks (DFNs). Complex fracture networks presented by DFNs are automatically extracted based on the gradient Hough transform algorithm (GrdHT). Smooth joint logic (SJL) is employed to avoid the artificial roughness effect from numerical discretization. Improved constitutive laws are also implemented in the modified LSM to calculate the realistic normal force-displacement from rough contact deformation. We validate this presented framework through theoretical solutions. It shows the potential for reconstructing actual structural attributes and quantitatively investigating the fracture attributes and microscale surface roughness effects on elastic characteristics.