Abstract
Water flooding is a commonly used technology for enhancing oil recovery. Its main mechanism is to maintain higher pressure to sweep oil towards production wells. However, the strong water flooding will cause higher compression pressure around the injection wellbore. This high pressure in the reservoir causes stress redistribution and higher stress near the wellbore which induces material damage and permeability change. We developed a fluid-solid coupling finite element model to simulate and quantitatively analyze the pressure evolution in the reservoir as well as damage and permeability change in the formation during long-term water flooding process. The obtained results offer theoretical understanding of the benefits (pore pressure increase in the simulation domain), rock damage, permeability change of long-term water flooding, and the insights of how to detect and prevent wellbore failure and collapse due to water flooding.
Highlights
Water flooding is a worldwide used technology for enhancing oil recovery
After 5-year water injection, the maximum pore pressure is 13.8 MPa, which is 38% higher than the initial value
In the area that is 30 m far away from wellbore, the pressure is higher than the initial value by over 10%
Summary
Water flooding is a worldwide used technology for enhancing oil recovery. Its main mechanism is to maintain higher pressure to sweep oil towards production wells. An axial symmetrical fluid-solid coupling finite element model is established to simulate the water flooding process. The pressure evolution in the reservoir as well as damage and permeability change in the formation during long-term water flooding procedure is studied. The formation damages gradually near the water injection wellbore and in the damaged area, the reservoir permeability jumps up. Rock damage and permeability change near the wellbore should be considered when planning a water injection well due to the potential risks. The present model can be used to predict the formation pressure evolution and the formation property variation caused by water injection.
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