资源环境科技发展态势分析平台

The injection of reactive fluid into fractured reservoirs is relevant to many subsurface processes. During injection, fracture dissolution forms various patterns. Despite its importance, the evolution of geometries in radial fractures remains unexplored experimentally. Here, by flow-visualization experiments, we characterize dissolution patterns and show that the patterns shift from compact to wormhole to uniform as flow rate increases. For the first time, we observe dissolution hotspots with maximum local dissolution rate in radial fractures, occurring at a distance from the inlet. We elucidate the key role of gravity for the occurrence of hotspots. The location of hotspots corresponds to the state that the effects of transport in the horizontal and vertical directions are comparable. We establish a theoretical model for predicting locations of hotspots in good agreement agreement with experiments. This work demonstrates transitions of dissolution patterns in fractures and reveals the underlying mechanism for dissolution hotspots previously unidentified.