Impact of Oil Degassing on Water-Driven Development Dynamic Indicators

This paper focuses on the issue of increasing viscosity in formation oil due to degassing and its impact on the dynamic indicators of water-driven development. We explore the effects of changes in formation oil viscosity on oil-water relative permeability, utilizing steady-state core displacement experiments. The research further delves into how variations in formation oil viscosity impact the dynamic indicators and efficiency of water-driven development. The study shows that oil degassing significantly affects the oil-water relative permeability curve and key dynamic indicators of water-driven development. As the oil viscosity increases due to degassing, the relative permeability curve of oil and water undergoes significant changes. Experimental results indicate that the isopermeability point moves towards the lower left, resulting in a reduced area of equal permeability and increased resistance to oil-water flow. This shift leads to increased residual oil saturation and pronounced non-piston displacement characteristics, ultimately resulting in a decrease in water-driven efficiency. Therefore, it is crucial to consider these effects when determining the timing of water injection, calculating water-driven development dynamic indicators, and conducting reservoir numerical simulations. Additionally, attention should be given to the alterations in reservoir and fluid properties in oil degassed areas. Utilizing the modified relative permeability curve is highly recommended for an accurate assessment of these changes.