Simulation Study on the Morphological Changes of Acid-Etching Fracture Surface Under Stress

Carbonate reservoirs commonly use acid fracturing process technology for reservoir reconstruction. And non-uniform etching features play an important role in slowing down the fracture closure and maintaining the high conductivity. Currently, the simulation studies about the morphological change process of the fracture surface are generally geometrically simplified for the morphological features such as the micro-convex structure, resulting in the model not reflecting the true situation of the non-uniformly etching fracture surface. In this paper, limestone cores are selected for acid-etching experiments. The 3D model conforming to the true morphological features is constructed based on 3D scans of acid-etching cores. By ABAQUS software, simulate the morphological changes of the fracture surface under different rock mechanical properties and stress loading conditions, comparing and analyzing the variation of results between this model and the conventional simplified model. The result shows that compared with the convention model, this model can accurately reflect the stress and strain distribution on the non-uniformly etched fracture surface. And with the increase of stress load, the fracture surface roughness decreases continuously, and the supporting effect of the micro-convex structure decreases, leading to further or even complete closure of the fractures.