Influence of Capillarity on Relative Permeability in Fractional Flows. Issue 11 (20th November 2020)

• Record Type: Journal Article
• Authors: Zou, Shuangmei; Liu, Yang; Cai, Jianchao; Armstrong, Ryan T.
• Is Part Of: Water resources research. Volume 56:Issue 11(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-11-20
• Subjects: capillary pressure gradient -- fluid distributions -- interfacial curvature -- multiphase flow -- relative permeability; Hydrology -- Periodicals; 333.91
• DOI: 10.1029/2020WR027624
• Languages: English
• ISSNs: 0043-1397

Abstract

Abstract: The effect of capillary pressure on multiphase flow is described by the capillary pressure gradient term in the fractional flow equation. This term is typically neglected during core‐flooding experiments, as it is not easily accessible. However, the capillary pressure is not constant during core flooding owing to a capillary pressure discontinuity at the core outlet. By imaging spatial fluid distributions under two‐phase steady‐state flow, we determine in situ phase saturations and capillary pressures from interfacial curvature measurements along an entire core, thus achieving the assessment of the capillary pressure gradient and its influence on multiphase flow. We demonstrate how the pore‐scale capillary pressure gradient affects multiphase flow and, in turn, the core‐scale relative permeability measurements. Further, an alternative approach to determining relative permeability from a single fractional flow experiment is proposed. The approach provides a range of relative permeabilities for a single fractional flow experiment and does not require capillary‐end correction, as the formulation directly accounts for the effect of capillary pressure on the flow. Key Points: The capillary pressure based on interfacial curvature measurements is comparable to the experimental measurement by mercury intrusion Relative permeabilities can be measured from a single fractional flow experiment by accounting for the capillary pressure gradient Relative permeability is measured which does not require differential pressure measurements, being entirely based on capillary pressure