InterPore2025

Microscopic Mass Transfer Mechanism of Oil Recovery Coupling Displacement and Imbibition in Matrices and Fractures with Different Pore-Throat Structures

21 May 2025, 11:35

15m

Oral Presentation (MS12) Advances in computational and experimental poromechanics MS12

Speaker

Prof. Renyi Cao (China University of Petroleum (Beijing))

Description

Displacement-imbibition coupling oil production is a critical technique for enhancing oil recovery (EOR) during water injection development in tight/shale reservoirs. However, the role of pore-throat structures in reservoir rocks during displacement-imbibition processes and their impact on microscopic mechanisms and flow dynamics at different pore scales remain unclear. This study integrates pore-scale numerical simulations and core-scale nuclear magnetic resonance (NMR) experiments to monitor the entire migration process of oil and water phases. The microscopic utilization characteristics and influencing factors of pores at various scales are quantitatively investigated. The results indicate that displacement-imbibition coupling oil production, driven by multiple driving forces (displacement and imbibition interactions), effectively achieves balanced utilization across pores of different scales, making it a superior EOR method. The key mechanisms of displacement-imbibition coupling oil production involve pressure oscillation and capillary imbibition. By artificially altering the pressure field within the matrix pores, pressure oscillations between pores are induced, enhancing the capillary imbibition effect, reducing the utilization threshold of pore throats, and promoting oil recovery. The pore-throat structure of rocks determines the effectiveness of displacement-imbibition coupling oil production. Rocks with higher heterogeneity and better pore-throat connectivity reduce resistance to oil and water movement, enabling more effective utilization of the coupling mechanism and improving pore-scale recovery efficiency. Additionally, the complexity of matrix-fracture interactions significantly affects fluid exchange during the displacement-imbibition process. More complex contact relationships between the matrix and fractures result in a larger contact area, facilitating the displacement of oil droplets from pore spaces and enhancing imbibition between the matrix and fractures while weakening displacement effect. These findings provide theoretical insights into the mechanism of displacement-imbibition coupling oil production between the matrix and fractures and offer guidance for the efficient development of tight/shale oil reservoirs.