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Numerical simulation of oil and water two-phase flow in fractures with rough surface considering dynamic stress effect |
WANG Dongying, YAO Jun, SONG Wenhui, SUN Hai
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(School of Petroleum Engineering in China University of Petroleum (East China), Qingdao 266580, China)
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Abstract: |
The relative permeability and capillary pressure curves of oil and water flow are commonly used as important indicators to describe the flow characteristics in fractures. Considering the effect of dynamic stress, an invasion percolation model was applied to simulate oil and water two-phase flow in fractures with rough surface. In this work, a single fracture model was firstly constructed using a method of Monte-Carlo stochastic simulation. Then, a steady-state displacement process was simulated to numerically solve the relative permeability and capillary pressure curves. The accuracy of the new model was verified by comparing with the Mualem model. The impact of dynamic stress upon oil and water flow was characterized using an analytical relationship between the effective stress and fracture aperture. The results indicate that, as the displacement process continues, the capillary pressure curve is moved upward with the increase of effective stress, where the oil relative permeability decreases but the water relative permeability almost remains unchanged. In addition, during the displacement process, the water saturation corresponding to the initiation of oil phase flow decreases, and the water saturation corresponding to the cessation of water phase flow decreases. |
Key words: single rough fracture relative permeability capillary pressure dynamic stress invasion percolation model |
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