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Pore-Scale Experimental Study of Free Gravity Drainage Process in Fractured Porous Media: the Role of Affecting Parameters on Matrix-Fracture Interactions

Peymani, Mohammad Amin | 2024

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 57383 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Ghazanfari, Mohammad Hossein; Fatemi, Mobeen
  7. Abstract:
  8. Natural fractured reservoirs are of significant importance in global oil production, and one of the production mechanisms from these reservoirs is gravity drainage. Previous research has focused on understanding the factors determining oil recovery from blocks during gravity drainage, such as fracture aperture, block angle, stability, and the number of liquid bridges formed at various angles, as well as the effect of injection rate. However, the results from these studies have not been sufficiently consistent and have shown ambiguities in the influence of the mentioned parameters on the dynamic discharge of oil from the matrix block during gravity drainage. These ambiguities highlight the need for further studies in this field. This research aims to investigate the impact of the mentioned factors on oil recovery from the block by designing a single-block system and a three-block system using a novel research method for creating different wettability conditions in a micromodel system. The results of this research demonstrate a new trend in changes in oil recovery from the block at different angles and variations in the stability and number of liquid bridges at different angles. It was observed that with the increase of the block angle from the vertical position to 20 degrees, the capillary continuity decreases due to the change in fluid flow path. However, with an increase in angle from 20 degrees to 40 degrees, the capillary continuity strengthens due to the increased stability of the liquid bridge, resulting in higher oil recovery. This trend was observed at two different injection rates. Additionally, the effect of the injection rate on oil recovery from the system was examined when capillary continuity between the blocks was established, showing that increasing the injection rate increases oil recovery from the system. Moreover, this research investigated the impact of the system's wettability on the stability of the liquid bridge, finding that with the decrease in the oil-glass contact angle, the stability of the liquid bridge increases. However, this increased stability does not lead to higher oil recovery because the capillary pressure in the matrix environment also increases due to the reduction in the oil-glass contact angle. Additionally, the effect of fracture aperture on the stability and number of liquid bridges formed was examined, showing that an increase in the fracture width reduces the number and stability of the liquid bridges formed. Furthermore, this research attempts to justify the slower discharge of oil from the block when the block is angled by presenting a new relationship for the movement of the oil column within the fracture. It was also observed that in the single-block system, with an increase in the block angle, oil recovery from the system decreases, and this trend was explained by presenting force balance equations
  9. Keywords:
  10. Pore-Scale Model ; Forced Gravity Drainage ; Liquide Bridge ; Matrix Tilt Angle ; Free Fall Gravity Drainage ; Matrix-Fracture Interaction ; Fractured Porous Media

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