Numerical simulation of fracturing and imbibition in shale oil horizontal wells

• DOI: 10.1016/j.petsci.2023.03.024
• Publication Date: 2023-03-28T16:05:30Z
• Authors: Rong-Li Xu; Tian-Kui Guo; Xiao-Jia Xue; Wen-Bin Chen; Zhan-Qing Qu; Ming Chen; Zun-Peng Hu
• Keywords: Imbibition; Capillary pressure; Reservoir Simulation; Saturation (graph theory)

The shale oil reservoir is characterized by tight lithology and ultra-low permeability, its efficient exploitation requires the technology of multi-stage multi-cluster hydraulic fracturing in horizontal wells shut-in imbibition. After fracturing, a complex fracture network formed, large volume frac fluid stored within network. During shut-in, imbibition exchange between water occurs under action capillary force osmotic pressure, formation pressure builds up reservoir. On basis characteristics reservoir, we establish model during injection coupling oil–water two-phase flow saline ion diffusion fractures (HFs) network, natural (NFs) matrix system pressure. DFN method multiple continuum are introduced to characterize HF NF that respectively, which avoids problem amount computation seepage fracture. Then, discrete (DFN) solved with finite element method, it verified field, saturation field concentration models accurate reliable. We propose for quantitative evaluation degree calculating volume. Simulation stages performed based on these models. It found driven mechanisms difference, only cause an increase rate reduction equilibrium time do not lead variation peak reduced from 150 45 d compared difference. If reached, low initial saturation, strong rock compressibility, high salinity permeability enhance leakoff generally larger than exchanged Leakoff slightly earlier equilibrium. mainly affected density. number interconnected affects process. stimulated (SRV)